My definition of Ambience

[PeterSt]

So, this time I won't call myself "controlversial" as such, and merely through to come up with a definition - or recognition of it, determined by mere technical means.
Btw, I knew I had a small chat about similar, which was this : The next level in SQ;

The "$$" mention in there was about quite something else, but expecially combining with what I use today (Orlino Speakers) I now see the light and merit.

First off, call me thick; I mean, why do people often ask to play something live (at auditions and such) ? Well, I guess they want to perceive some ambience. Or how it works out once it should be there, like with a live performance (though recorded). Also, it is clear to me, and maybe not to me only, that something like the XXHighEnd/NOS1 combination incurs for the more leightweighted playback; Don't get me wrong, because all I refer to is the better means of playback which removes "illegal" low frequencies. So, NOS1 does nothing, XXHighEnd tries its best, and next we may require some more "body" than we are used to. Is that justified ?

It depends.
Let's first look at some weaker proof, but which I will use anyway : Controversial post and new Setting. So, this recent topic tells me that nobody gets even close to what I now can perceive here. Not agreed ? then you had to post in there I'm afraid. But no need, because I (still) think I know a few things, and what I now can do with low frequencies is unheard. Literally. And sorry.
And to keep in mind please : the speakers/system I have been using for the past 5 years were regarded the best by many (almost all) who auditioned here, especially in the bass department. So, what I have here now is nowhere close even the slightest to that. NO-WHERE. And ok, I can't describe this anyway, so everybody will say "oh well". One 100% promise : don't you ever think you have any bass as such, no matter how low your speaker goes.

Thus, the last link referred to a simple XXHighEnd settings-change which is even very familiar to many. To all (that I can see) it doesn't do a thing, as it did not with my former speakers. Fine. But here it is the difference between a hand-held fire cracker and a 911 explosion. PeterSt, good for you man.
Yea.

But what it brings me, and the reason for this topic, is the sudden recognition of how "ambience" emerges. And no, I am not talking about the Pawnshop idiocy, but how ambience exists in everything. Thus also studio recordings.
And did I not promise that (see first link) ...

Now (and this is in aftermath for me), suppose you went to this live concert. Make it in a hall. What do you actually hear in there ? I think, outsize the buzz of people talking, this is a kind of roar. Very low frequency roar. It is the hall talking to you, and the larger hall may talk at lower frequencies than the smaller (studio) one. Of course this is nothing different from how in our rooms the low frequencies emerge from our speakers, those anechoically (outside etc.) going to e.g. 35Hz while in our room they make 25Hz of it.

In between the lines and not sure how it works, and only knowing that it works : for these speakers this does not apply (at all). So, at very close distance (like a few cm up to a meter or so) I measure the lowest frequency for its relative SPL. More in-room this only gets higher (read : for the same relative SPL the lowest frequencies drop out). Never mind this for the real merits, but I think this is not so normal. To me, the fact that the room does not make the frequencies lower, it tells something like the room not being at work at all. And this again is very much related to the subject (because it allows to perceive the ambience of the recording room better).

Now first a bit how music has started to sound :
Each hit on a base drum up to a floor tom, receives a more or less crazy umpf which can't come from anywhere in your perception. Only heavily tuned up bass (woofers) could somewhat do it, but it would colour as hell. This does not. What you actually hear is a large dose of hall and then the kind that turns into the lower frequencies compared to the fundamental. So, base drum is hit at (virtual) frequency X, and the hall in the room makes that X minus Y.
Which room ? well, not mine. The one where the bass drum was recorded in, yes.

The above will be a mere weak explanation as how it sprung from my mind, and again you can say "oh well". Also you can easily say "I have that too my friend".
True.
And when I try to check these things by feeling the woofer's diaphragms, all I can feel is that there's indeed a very low frequency going on at the hits. Sadly, a sustained frequency as such is not in order with drums, and all you'll feel is the low "rumble" in aftermath of the hit; could just as well be normal.

Yesterday I played some live music and what I already noticed a week or two ago, is that the ambience of live music goes a bit crazy. I mean, when I am as far as perceiving studio recordings as sheer live, what about the real live recordings ? So I started to pay attention to what I actually heard, clearly "seeing" that it was not about audience voices or hand clapping.
The nature of it is a bit hard to describe, but without music playing (the artists changing guitars or whatever), envision a darker background rumble of a large space, which after closer thinking back on the music you just heard, just resembles the whole character of that band playing. But now the band does not play.

Finally coming down to the matters ... I again felt a woofer and was shocked. Excursion of undefined frequency was going on, and I'd say at almost higher excursion levels than any sub low bass playing. And part of my fun : I felt a similar movement as I felt earlier while such a low bass actually was playing. So, at that time I could not think other than "okay, complex bass", but I know now that what I actually felt was the response of the room over there on top of the bass frequency.

Of course, any new definition of "ambience" is not needed. But I now know where it happens : in the sub low frequencies which need to be treated in total freedom. So, put on a live recording taken in a larger hall. Play at reasonabvle levels like 85dBSPL. Feel your woofers in between (gapless) tracks. If you feel an excursion of something like 5mm to one side (1cm in total) you can consider yourself lucky to some extend. But I don't think it will happen at all. Of course this depends on the total woofer surface. So, if your 10"er makes these moves after all, don't forget to do the math for what happens when that 10" was 3x12". Any comparison is allowed of course, and you can count in your real sub woofers.
But unless you come to comparable air movement math and with the notice that it is quite fine to let your one 12" excurt 3cm if it can do it, you won't know by miles what I am talking about. Remember, normal 85dBSPL and not allowed to tune up the bass into colouring.

Anyway, all I tried to do was laying out where the real ambience comes from when it is to come through loudspeakers. For myself this is new and I don't think it can easily happen. Thoughts from others are welcome of course. I make up too many things anyway.
But don't think it is turntable rumble what I experience.

Peter

[BertD]

...especially combining with what I use today (Orlino Speakers) I now see the light and merit.

Are you not writing about the Orelino's? 

I guess I'll have to come over again pretty soon to experience those things you are talking about...

I am pretty close to the final revised crossover for those Orelino's, no worries, these will not take away any of the ambiance but merely cleaning your glasses so that you can see through clearly... 

Bert

[juanpmar]

Hi Peter, could you let us know some of those recordings you were using to test the woofer movements between songs?. To test it in our systems we should have, at least, the same recordings.

Juan

PS. Don´t get me wrong, I don´t see it as a competition between our speakers, on the contrary it seems to me a very interesting observation and a new way to perceive the ambience (and a way to "touch" it)

[PeterSt]

Hi Juan,

Your question is fully justified of course and I thought of it myself. Point is though : I only very recently found this myself and on recordings/albums you won't have for almost sure (because Dutch, Nits - Urk if you want to know). But it should be easy to run into many more ... however ... it is not easy at all to run into many more which will be commonly known; I just don't play the commonly known stuff often because it doesn't have my interest (read : it costs time while I have so few of that). But real life example :

Last week Bert was here and we both listened just before my prepared filter worked for the last time as intended, and I thought to put up an album Bert played for me when I heard the OrElino at his place for the first time; thought to let sniff Bert somewhat on the current achievement. So, started out with The Turtle Creek Chorale - Requiem and Five Anthems (Reference Recordings), Agnus Dei (track 09). This is played/sang at a very low level and is in a church.
Within 3 seconds (I am serious) Bert asks me to put on the next track. I did not understand and thought I had put up something stupid to listen to. Instead Bert told me "hey, *you* have ambience here !" ... and so he knew enough within those few seconds.

Bert, if I am lying I am sure you will jump in.

And this was before I was able to pull out that even more crazy bass and lows with XXHE settings which happened 3 days ago ...

Anyway, since this is a possibly more known recording I could play it again, feel the woofers during those first few seconds and let you know.

One other notice which may be a bit premature :
Not from the last three days, but from a week ago when my filter was still OK (and hus without the XXHE new settings) I set myself to the "definition" that older recordings don't have any of this. So, not the Deep Purple's, not the Led Zeppelin's and not the Uriaha Heep's, to name a genre where it would be so nice to have it in there. Planned to try Nirvana's Nevermind, but ran into Massive Attack instead and that sure has it (to stay in the genre at a distance ). Anyway, this may tell that before some era - or the recordings just could not contain this sub low, or they could but it was filtered out because it can't be on LP. As I said, a bit premature. But by accident I was sorting out electronic music from before the 80's comparing that to the modern albums from today (our son had a school assignment about it) and in those pre-80's there is nothing of it. So, this is synths which can do it easily, but they apparently did not (think Tangerine Dream from back then). Today, all "ambient" without exception has sub low. Not that I knew that 2 months ago. Only Yello and the more explicit "sub low" ambient could show it, but at analyzing it this isn't even real sub low (won't go under 25Hz).

On the latter too I recall a session with Bert, he being sure that some Hatfield's End (also Dutch) album would go the lowest of it all, but it is very easy to be deceived and it really was not at all (27Hz maybe).
And no mistake, I would have said the same without really knowing now, which foremost is a matter of recognizing the frequency. This by itself is a completely different matter, because where we tend to think that we can only recognize the more higher frequencies (like 100Hz is easy) and the lower ones (like 23Hz) are only low sound, they really really are not. But they need to be "straight" or otherwise it goes into a dark airy sound only which your SPL meter sure will show, but which is not that intended 23Hz.

Before it gets lost in all my words, remember that this "ambience" is not about frequencies as such; instead it is about the most unregular excursions or maybe better put, long term reflections which may have met 24 walls before they hitted the microphone. You can feel them stack up with the reflections which hit only 6 walls yet. At least that is my idea about it.

So, playback time starts here. Will try that Requiem ...
Regards,
Peter

[PeterSt]

So this one : http://www.amazon.ca/Requiem-Anthems-Turtle-Chorale-Womens/dp/B00000159K

No "rumble" as such here at the start of track 09. But instead you may try the end of track 08 (Sanctus) where a few guys with paukes go wild; here you can easily feel how the reverberation in the church makes much more happen than the hits on the paukes.

Anyway track 09;

I am fairly sure a 32' organ pipe is at work here, although it is my opinion that this is not 16Hz (for 32') and not 32Hz either. So I don't know whether 48' exists, but if so it is that. The 32Hz is easily discernable later in the track.

Not much worth on the subject, but what I noticed in the beginning of this track (say first 30 seconds) that there's this constant nice frequency of something I'd say is 24Hz of the organ, but that this is always interrupted with the pauke hits (very softly hits). Remember, I am feeling the woofer(s). I can add that at these low voiced paukes they don't play in the woofers at all (but compare the end of track 08 when they do wildly because of church reverberation). So, seems a bit strange to me. Woofers are fed by a separate amp, so it's not that either. Cancellation in the church ? can't imagine that.

That's all for this one !
Peter

[juanpmar]

Thanks Peter, I´ll look for that Requiem although I´m not sure if I have it. However, as you explain it, it seems difficult to perceive the ambient frequency without confusing it with other frequencies. Anyway, I will try it to see if I can "touch" it.

Juan

[PeterSt]

I forgot : You can easily feel how one larger hit on a pauke lasts 5 seconds easily in that church.

[juanpmar]

I´ve found the album and I´ll test it when I return home in a couple of hours. Just to help me to understand it better, what does "pauke" mean?

Juan

[PeterSt]

Oops, I am sorry Juan. The translation says kettle drum, but I wonder. Anyway :
(standard instrument of a large orchestra)

[juanpmar]

Concentrated only on the first minute of the track 9 - Agnus Dei , from the album Requiem (Reference Recordings), this is what I perceived:

1 - Touching with my hand the 15" woofer I perceive the vibration from the first second to the second 39.

2 - From my listening position, from the first second to the second 10 I hear softly the kettledrums but I do not hear the low frequencies. At the same time I perceive a sense of space or "ambience" to an acceptable degree. Between the second 10 and the second 39 I hear the men choir in addition to the kettledrums, at this time the perception of ambience is very high and still I don´t hear the low frequencies. From the second 39 on, when the female choir enters, the space becomes shallower and flatter with the female vocalists more in front. The sense of ambience decreases significantly.

Relating 1 and 2 what I can see is how the ambience is perceived with more emphasis when the woofer is vibrating between the second 1 and the second 39. So I´d say that although the woofer vibration can´t be heard it contributes to form the ambience.

I should, however, experiment with some other live recording, perhaps also recorded in a church, without those low frequencies, just to see if the ambience is also correctly reproduced.

I would like also to point out something that has to do with the construction of my speakers and how they reproduce the ambience. I think it's a way, perhaps complementary, to address this issue .

This is an excerpt of the Von Schweikert VR- 9SE  manual:

"ACOUSTIC INVERSE REPLICATION
Additional research led to my further discovery that recording microphones encode the musical signal with their overlaying pickup response patterns. After making a series of recordings, using several different microphones, it was obvious during playback that the mics not only had tonal differences related to frequency response errors, but also created different types of imaging patterns. The perception of depth and space was not only dependent on the recording environment and mic placement, but also on the mic’s off-axis polar response. For this reason, I decided to engineer an adjustable ambience retrieval system radiating from the rear of the VR speakers, in able to recreate the space and depth heard in the concert hall when the spaced omni method of recording is used.

Thus, a correctly designed speaker system should project the inverse of the mic signal, acting as a decoder to translate the original sound field. I have termed my design for this decoding as Inverse Acoustic Replication, and the Virtual Reality series of designs was developed from several important concepts related to microphone pick-up patterns. These concepts are based on the consistent phase/frequency relationships in the polar response pattern of the mics, which was later reverse engineered into the VR speaker systems."


For a more complete information on how this speaker reproduce the "ambience", and only with the intention to give other perspective, I´d recommend to read the Technical Information starting in PSYCHOACOUSTICS
http://vonschweikertaudio.com/vr-9se-mk2-technical-information/

Juan

[Jud]

Yes, those are "kettle drums."  One of these is more formally known as a tympani.  (TIM-pun-ee.)

My go-to demo for the sort of live bass "rumble" you're talking about has always been the opening track of Keith Richard and the X-pensive Winos "Live at the Hollywood Palladium."

[PeterSt]

Hey Juan, great story.

That description of the VR made me think that the mic used in the recording possibly was not able to capture that low frequency (I still say 24Hz) together with the higher ones ? So, about the organ disappearing at each kettle drum hit.
Here, the organ is very much audible in that first 29 seconds and it really energizes the room.
I do this by heart now : What I don't see you writing is about the (by me perceived) 24Hz turning into 32Hz, which or happens after this 29 seconds, or maybe a "measure" later (and IIRC the 24Hz never reoccurs in the track). This is more of the "zzooming" tone like 32Hz already does it, with maybe the reference to our well known 50Hz (60Hz for US) which we hear more often.



Yesterday I tried to find some of the real thing for you (all) but I had to focus on some music of general interest. This is not so easy, and while I tried two albums I actually failed on it. I described what I heard anyway, just in case I would put it through to you. So, this latter I do not (you would not like the music IMO), but here is how I described the both anyway :


This is actually fairly nice background music. Can't hurt to obtain it. Synth resolution is sure there, but mostly not exploited.

Track 01 : 22 Hz to my estimation. Whole track is formed by it. Watch the evenness of the different low key notes. Hits are DC like.

Track 02 : Also a lower frequency but square. Melody will be still perceivale because of the higher frequencies implied by the squares.

Track 03 : Won't do much without the sub low. Fast gliding frequencies which I estimate on 10Hz (DC like) to maybe 30Hz.

Track 04 : Same as 01 but could be perceivable still. Audibly changes from 25Hz to maybe 60Hz or so. Melody is in the low end only.
Only interesting because it fills the room nicely. Otherwise much of the same.

Track 05 : Boring, should skip.

Track06 : No, I stopped.

Life is ...

Track 01 : Space ships and pure deepness. Great resolution. Notice though that the "pauke" (kettle drum) like sound is not low at all. The low starts at 2 minutes or so into the track. This gets more and more low and room filling. At some stage, when things start to fly all over, the low is getting more square and you will for sure perceive that (implying higher frequencies). More later into the track this square lower freq sound receives body of very low freq. and all starts to e very airy. It dominates the track.

Track 02 : Seems to start low but is not at all. 20 seconds into the track it starts to happen and hits imply 20Hz short blasts while the freq maybe is 40Hz and implies the melody (40Hz and 60Hz I'd say). When voices start to sound the real melody starts and seems to be 30Hz. In the mean time I feel something like 18Hz. This is the main melody of the track, hammering your stumache.

Track 03 : This is the only track from this album I have in my "Demo" Gallery and it is there for its suberb bass. That bass is still very firm and in 4 sections of this 20 minute track it reoccurs, each time a bit more firm than the previous time. First time is 2 minutes or so into the track. However, knowing a bit more today this really is not lower than 200Hz. Woofers hardly play a role here. But, at the second part the drums start, and *they* feel like 20Hz or so. Aha.
In the mean time (during this typing) I perceive low frequency roars with heavy impact. I'm always to late to catch it at the woofers. Then (7-8 minutes ?) the rototom part starts and the whole sound is influenced by LF hits on whatever it is. All new to me.

Track 04 : Seems worth nothing much. Untill the general female singing stops. Then the LF kicks in and remains dominating the track.

Track 05: No real melody here, but all about the sub low hits throughout. Interesting for me, but I may be the only one. Only towards the end some real profound small melody happens at maybe 30Hz.

Track 06 : The beginning of this track, funnily enough, produces more (very) low freq energy than I could feel. It sure was there, but to my belief nothing I could hear. Still I did.
Here I stopped.


Peter

[christoffe]

Low frequencies

this is an exerpt from
http://barefacedbass.com/technical-information/Huge-lows.htm
-Quote-
20Hz - 40Hz = rumble
These are the kind of lows that are felt more than heard and add a certain rumble and sense of scale to movie soundtracks, pipe organ music and some electronic music. The sub 30Hz realm is very much sound effects territory - explosions, thunder, et al. There is very little content in music below 30Hz so club systems tend to cut off at this point if not a bit higher, whilst live music systems as seen at major festivals / stadiums tend to cut off at 35Hz (which makes the systems a bit more efficient so you need less gear to reach a given SPL than with a system with a 30Hz cut-off). A low tuned bass guitar does have output below 40Hz but it takes a seriously potent speaker system to reproduce that at high SPL. Sub 40Hz output adds a certain size and weight to music. It is almost more felt than heard and is rarely perceived independently of higher bass output (because any low frequencies will have higher overtones). A good word for it would be rumble. A bad word would be boom (boom happens much higher up).
-Unquote-

A nice sample with an amazing deep bass is
http://www.amazon.fr/Fabuleuse-Histoire-Swing-Michel-Jonasz/dp/B000F39MI8/ref=ntt_mus_ep_dpi_7

Disque 2 - tune 2

Joachim

[PeterSt]

Hey Joachim,

That Jonasz could be a nice subject to talk through and I will try to get that album and see.

But let me tell you ... the more examples you all come up with like these (20-40Hz = rumble and such) the more personally me is going to change audio history;

Might it not be clear by now, those frequencies from, say, 23Hz and upwards are all the most discernable here, and I promise you it is not my ears. In addition, notice that I let run FFTs (they show the frequencies playing) and that these frequencies (up to some 16Hz as it is right now) perfectly show, PLUS that I can see that no harmonics are there hence when/that it is a nice sine playing. Keep in mind the importance of this, because it shows that no higher harmonics can fool me in thinking I perceive the low tone while actually it is a squarer one and I thus perceive the harmonics.

I say it again : It is really odd to notice that these very low frequencies really are perceived a such, and a downside : that when two completely different albums play a same frequency in pure sine fashion, they really sound 100% the same. And why not. They should. And so as I told elsewhere, it is very rare that more than one frequency plays in these very low registers, and thus it becomes profound how they become the very same over different albums. But if two albums would play a 1Khz sine, that also sounds exactly the same. And of course it should.
Luckily most "gag" (I call them by now) albums which explicitly utilize those very low frequencies (like under 25Hz) will not use a stupid sine but any (combination of) waveform(s) so they will not sound all the same. Besides that I'd say in 50% of times they let the frequencies glide and no album will utilize that in the same fashion.

About the rumble and your explicit reference to it :
Maybe I have not been clear enough; when I perceive that rumble, IT IS RUMBLE. So, if you read back you can see that I talk about no clear frequency at all. Thus rumble, not now from the more technical side of things and felt from the woofers. Also see my reference here and there to "DC like" with which I try to refer to one-time excursions, but "like" because they are built up with underlaying rumble of different occurence and level. The best "expression" I could obtain from the end of that Sanctus track is the kettle drums which are used so massively that the whole lot starts to form a longitudinal in that church back and forth bouncing pressure  wave. On the woofer you can feel the collisions happening and in realilty it sounds like thunder.

Anecdotical :
During the X-fi 2012 show we "discovered" that the Big Orelo speaker (4x15" in similar open baffle format) with one of the tracks we played could form such waves. This was about a lower frequency more square sound, and it let glide the frequencies used. This allowed the wave length to reach the length at the room precisely, once in the X seconds of the glide passing that exact frequency. This too emerged in back and forth thunder, and the audience dit not know what was happening to them. For me the sensation was that the whole room was moving back and forth, similar to yuo moving your head forward to the speaker and backward again. But your head does not move and I suppose the room did not either (but we played this at apporx 120dBSPL);
This too is sheer rumble as such, though made excessive through high SPL (same with the kettle drum example). Furthermore it is my thinking that back and forth bouncing sound waves imply a magnitude of lower frequency, just because of the misformed frequencies, and it will be similar to a speaker outputting more LF when in-toom than anechoically. In the end it is just distortion.

Remember my telling about those kettle drums not expressing in the woofers AT ALL when played at softer levels. And I don't see much reason for when hitting them harder the frequency getting lower. This, opposed to the end of that Sanctus track where those same kettle drums, and only those, create nothing else than sheer rumble with the woofers highly excurting and with indeed "rumble" as such felt. But all you really hear is church hall and things turning into a (meant !) mess.

Of course I can continue with this blahblah forever, but what excites me most is that now MY room does not do this at all. So 1. frequency is measured lowest close to the speaker and 2. nothing gets a mess no matter how loud whatever bass. And I say it again : At listening you just can not understand how this all keep on going 100% OK in the relative small room; That loud it can go without messing up.


But since I am trying to (re)write audio history anyway, let me now try to make up a technical reason of what really might be happening. Two things to keep in mind for the next blah :

1. Although closed or ported cabinets WILL imply distortion of the sound wave, I am NOT talking about that hereunder;
2. Even when a double bass (etc.) plays at 100dB continuously in my 12x8x3m room, there is no corner to be found where even the slightest standing wave happens.

So, in a closed cabinet, we can expect that the pressure waves have a forward character; the backward pressure ends up in the cabinet, is dampened in there depending on the caninet design, but anyway the pressure will be into the room. It can also be expected that the diaphragm plays more forward instead of in the middle on average. Pushes are merely forward and while the diver tries backward just the same, there it is dampened by the air pressure in the cabinet anyway. Ported designs will do the same, unless the port is as large as open space;

So what should happen is that with open baffle the forward pressure is as large as the backward pressure (count out the Orelino's specific design because then the story gets more complicated). Back and forth moving air is what we perceive for sound level and what our SPL meters can measure. However, since now the back and forth moving air is the same instead of forward only, the average of it is zero;

When this latter would be correct (and opposed to what is happening with a cabinet design), this does NOT energize the room. So what I'm actually saying is that if we'd put out our barometers we'd see no change in general air pressure, while with a cabinet design the air pressure would would rise (with the notice that the complement of it will reside in the speaker's cabinet).

Assumed I'm still on the right track, the cabinet would imply congested sound. Squeezed. The more loud we play, the more the sound will congest.
Not so when the air difference (average) pressure remains zero. Nothing congests and all remains "free sound".

When this would be the conclusion of how open baffle allows free sound, it is quite different from distortions not happening because of back chamber pressure. But now watch out :

I have forever and always been saying that distortion as such (no matter LF or higher F) implies standing waves. Now, I won't go into the explanation of that, but I for 100% assume this is the prequisite.
Next, I already don't perceive standing waves at all for over two years (the NOS1-USB removed the last little corner of it), so this would lead to the sort of conclusion that it may not be the now removed woofer distortion because of open baffle at all that implies that free sound. I could just be the zero-average sound pressure that does not congest the waves.

And to be honest, after writing this - all made up on the spot - "congest" sounds mighty opposite as "free" to me.

This latter makes me even think further, because a 2x "congested" 25Hz frequency will become 50Hz ... The louder you play the more congested it gets the higher the perceived frequency becomes.
I'm not sure I ever heard that per se because first the woofers must be able to put out that good wave form at sufficient SPL (which just means woofer surface without back pressure - period). And my previous speakers apparently did not, while these do. So how to test it.

Joachim, this was all not specifically addressed to you. However, we both know that you know a bit more about fine loudspeakers, and you know how my "old" system performed back in the days (say 3 years ago and a lot has changed for the better since anyway). So, you are amongst those who expressed that especially my "bass" was a sort of superb. But let me tell you (please), it was NO-THING. You just can't have the idea because it is an out of space thing.
And since you know me personally and will know a bit how I am and how I talk, you should be able to know what it means when I say "nothing" compared to what I have now.

Ok, sorry for a long post. I'm just too enthusiast I guess.
Peter

[christoffe]

Hi Peter,

thanx for this nice post, and I believe, it is time now that you give us a chance to participate with your enthusiasm via a small film on Youtube.

We are waiting eagerly.

Joachim

[PeterSt]

And Joachim,

While I read the article at a glance at first, I now read it in full and from there get your guesture;

No.

If you read all my blah about this speaker you will have seen that I will be the first person to recognize how higher frequencies hence harmonics from more square lower ones, are to deceive us;

You may also have read about me tuning this speaker flat to 17Hz and this is within 0.1dB (looking down from 100Hz). 0.1dB is nothing of course, but it hopefully testifies that I have been really really working on this.
(notice that right now it is -3dB at 18Hz because for commercial purposes the 17Hz is dangerous for the really higher SPLs)

You may also have read about my mere special means of getting there, and amongst that is looking at FFTs. You know, those thingies which show all the frequencies, thus harmonics.
And so I can guarantee you, that while I used this means to just simply see where the woofers start to distort (actually because of too high excursion), this obviously implied the observement of the speaker as a whole. And I can guarantee you that no harmonics (from a pure sine of course) can be seen anywhere.

Thus, the guy from the article is correct at this, but he assumes heavy THD from his bass bins in the first place, which would be true according to my own reasoning for cabinets.
Not so here at all. And with that your guesture failed.
But it was a good attempt of course. It's only that I was ahead long of it (thus see other posts elsewhere) and I think I know what I'm doing.

In the mean time the guy from the article refers to "rumble" of "some" electronic music in the 20-40Hz region, but this time the guy talks from his neck - which I would have done the very same 2 months ago. Really;
If you look at my pasted descriptions earlier in this topic from "ambient" music I tried to find for you all (or for Juan) you see me describing that complete main melodies play under that 40Hz and way lower (I play the same albums from before, but never heard any melody there in the first place). I did not talk from my neck there PLUS (and this should be kept in mind foremost) that this is not from false harmonics or more squared bass, because the a. false harmonics are not there as just described, b. it can easily be felt on the woofer when harmonics exist in the music itself (squares produce all odd harmonics in the world (3, 5, 7, ...) also knowing that any 25Hz would also play 75Hz which still is easily in the woofer region and c. that I have been looking at real live music playing through FFTs.
(and in the mean time I can not find any modern ambient album that plays NOT in this region explicitly)

Funny addition perhaps :
From the latter I learned that those hollow space ship sounds come from setting up a sine fundamental at e.g. 90Hz with now UNDER that harmonics like 45Hz, 22.5Hz which each decrease by 10dB or so. So the synthesizer plays 3 fundamental(ly related) sines here, and there is your space ship.

Peter

[PeterSt]

thanx for this nice post, and I believe, it is time now that you give us a chance to participate with your enthusiasm via a small film on Youtube.

We are waiting eagerly.

Believe it or not, but yesterday I was thinking of someone (forgot who) and to call the man by telephone and by this means I would be able to show him this crazy bass.
I am fairly sure this would work. Fairly, because this hardly can be about the low frequencies, but merely about the power of them (the guy from the article accidentally talks about this too) at the limits of the phone connection, in relation to the further music.
But it wouldn't make real sense because through the phone connection (or YouTube for that matter) one would not be able to judge colouring (which should obviously not happen, but would when the bass section would be, faslely, way tuned up).

Best regards,
Peter

[manisandher]

... and you know how my "old" system performed back in the days (say 3 years ago and a lot has changed for the better since anyway). So, you are amongst those who expressed that especially my "bass" was a sort of superb. But let me tell you (please), it was NO-THING.

Hey Peter, I also heard your "old" system. I remember listening to (your) Paul playing real drums and then comparing that to a recording you made of the same drums played back through your system. You may not have heard me, but I specifically stated that your system's LF impact was just a fraction of that of the real drums. If you're now getting close to the real thing, then I can't wait to hear the Orelinos for myself. The whole setup must be something truly special.

Mani.

[PeterSt]

A nice sample with an amazing deep bass is
http://www.amazon.fr/Fabuleuse-Histoire-Swing-Michel-Jonasz/dp/B000F39MI8/ref=ntt_mus_ep_dpi_7

Disque 2 - tune 2

So here is one example of what we may perceive as "amazingly deep"; I hope that you recognize a little what I'm saying :

Main "tune" of the bass - that being in 90% of the track throughout - is 55Hz. This is the round sound.
Funny for me is that I was spot-on with my perception of the lowest notes in there (ok, you won't believe that anyway, but *exactly*) is 38Hz. These are the once in a while occurring larger plucks (where the metal of the plucks is heard - at least here and which also doesn't need to show in all systems). The very last note in the track is that too.

So, amazingly deep is not so deep at all. But at least you implied (!) that this is a good example of the real low for you, and as far as I can tell it counted the same for me that few months back, including my 12Hz subs.

Another thing : That last "pluck" (in the last 10 seconds of the track) possibly is not perceived as the lowest in there at all. This is because this plucking implies those higher frequencies (see article) which you for sure will hear (apart from the fact that too is not all that easy as I just said above, but with XXHighEnd and NOs1 you should). Anyway, this really is 38Hz. So you can compare that nicely to the 55Hz which is all over the track. Btw, the two never go together. So it's or the 55Hz long sustained tones or the 38Hz plucks (but which also can sustain, see last 10 seconds).

Btw, a more normal album you all might have (outside of ambient I mean) is Zappa - The Yellow Shark. Try track 04;
The hits you hear in there (for sure) are all 32Hz. Not amazingly low either,  but notice that the 32Hz in this track is the loudest of the whole spectrum. So key is here that this 32Hz should blast in the room, knowing that the second loudest instrument in there is the oboe + clarinet (I think) and they play mainly at 400Hz).
With my previous setup this played as well - perceivedbly - because the 32Hz sound is square and its harmonics are easily heard and the more airy sound of the fundamental kept working well because it is so loud. I'd say this is not "room" reveraration we hear in his track which already can be seen in the FFT by the very straight and solitude fundamental.

Happy listening !
Peter

[PeterSt]

Hey Peter, I also heard your "old" system. I remember listening to (your) Paul playing real drums and then comparing that to a recording you made of the same drums played back through your system. You may not have heard me, but I specifically stated that your system's LF impact was just a fraction of that of the real drums.

Hi there Mani,

Of course I know, and I never forgot it. And knowing that you follow quite well what I say and claim "around the globe" you will have seen me writing possibly a dozen times that the only thing which made that self recording apart from live was the kick drum (base drum).
But you just reminded me, and I should try that recording again ...

Btw interesting within itself, because that recording so well represents the colours of the real live toms and all, even that kick drum (you will sure recall that too). So, if now only the real impact is there BUT the colour stays the same ...

Till later ...
Peter

[christoffe]

There are not that much instruments that goes below 30Hz, and therefore we need some records with a pipe organ (on a CD).

Ok, I see your post for Juan from the on 2013-10-08.

[PeterSt]

Ok, now I will be in raving mood and raving mode; I just played my Demo track #1.
Not that I ever knew that before I just played it for the very first time in my life ...

First off, this is about this recording session(s) which are all named "Base Drum". So, back at the time, July 2010, me and Bert set this up to test something I have forgotten by now, but obviously this was about the base drum and to test it through the audio playback chain. What came from this is the best recording of drums I ever heard in the universe, and up to today this is still so. I can't help that. Maybe I can, by not knowing how to molest recordings, hence all I did was giving the recordings a suffecient headroom and never touched a thing afterwards. Recording was through a FireFace800.
Nice.

What Mani referred to is the one recording out of the 9 we took and it were 9 of them (each being 5 to 15 minutes in play length) merely for placement of the two (measurement) microphones and how to give the drumkit the right size. Yea, what did we know. Btw it included the 30 meters or so XLR from mics to FireFace.
We played that track in San Francisco (show) a couple of times and people drooled (no matter the speaker perfromance). I planned to play it at last X-fi as well, but never got round to it. Things didn't work out there anyway, so I did not bother.

I just played that track to look at, hear, and feel the response, and the FFT was running (same microphone used, but now capturing the loudspeakers).
To discover similarities or whatever I wanted to see, I played about all the tracks just now for longer and smaller parts, trying to get the merits;

What I could see is that the base drum plays at 38Hz. Felt the woofers and what I actually noticed was the 2 seconds of "after vibes" at the base drum hits. So, went upstairs where the very same drumkit resides and thought to find reverb of the room.
Mwah, that could not be it, because the base drum actually is dry (short) as hell. How could that give any impact in the first place ? Felt the skin, and that really does not incur for after vibes.
Then, without real notice at first, I heart that all the toms (which are 6 or so .. yea, or so, easy to count hem of course) payed along with the base drum. Aha. Actually it's so that the dry kick of the base drum produces its real sound through all the toms in aftermath.
Hmm ...

Raving mode not so strong yet, I decided to play the last three tracks recorded. These were 24/192, while all of the others but one were 16/44.1.

Just *because* these are 24/192, I never listened to them. Oh, I recall to briefly listen to one of them, but since we're into CD Redbook maybe I didn't even want to hear whether it sounded better. Point is : I never listened to them, and certainly not the very last one.

Ah, you now think you see it coming eh ? Well, you won't !

The first of the two are a bit of the same as the others with the difference that the snare of the snare drum was off. This annoying always co-souding profounding thing should never have been in any of the recordings in the first place. So, good that's off - in all of these last 3 tracks. Now :

To start at the end (do I ?) that last track can well be the best drumming recording I ever heard in my life. This time though I refer to the drumming, not to the quality of it. Or ?
Well, if you only know it was me drumming there and also know that if I have been 20 times behind that kit all together, how ?? Must be because I like myself ? haha, maybe.

Part of this sheer excitement about me myself drumming there is the so-well rendering of all what's really there. Actually it is outrageous. So, that track I played more often, well, also nice, but what happened in that last track beats everything and all.
When it was finished I looked at the recording date and this was 4 days after that session of Bert and me. Must have felt good or whatever.

So ... raving mode at full trottle now ...
... but also back to the plain subject of this topic ...

What you hear me doing there is -somehow- trying to hit all the toms at the same time.
And, don't say that I didn't see coming what is in the various posts of this topic already ... how "ambience" emerges ...

While hitting the toms, which most clearly does not go in the most wild fashion, and which btw is a very first thing to notice from these wild speakers (meaning : how I perceive the very same from other recordings, all in the category of "air"), I glanced at the FFT again which was still running but which lost my interest because I thought I had seen it all already and ...

I see exactly what I already described earlier;
The hitting of those toms, a base drum underneath, goes all the way to 18Hz. And as how the FFT captures it - in a fairly flat fashion (all the frequencies up to wherever play in sequence, so no harmonics or anything to be seen. Call it rumble all over.

Listening to this - and what most probably makes me excited about a best drum track ever - is that you hear a sheer flow of nice warm water, while in the mean time all the real hits stick out so superbly. Swamped in music. Dwelmed in something which just matches and which I never heard before. A rumble which belongs to it all. And still by no means created by the listening room. All is so totally clear that again I wonder myself how it can be.

But 18Hz ??
Remember, this is no clear frequency at all. It's just from of just under 18Hz (the speaker's response) that the level goes up and it stays a sort of flat up to where the base drum shows its 38Hz and beyond that the higher heyed toms etc. And the mere interesting thing : None of this I saw in the other tracks. But also, none of the other tracks produced the running into eachother frequencies of the individually hit toms. There it were subsequent hits, while here I let all flow into eachother. Nothing different from the end of that Sanctus track where I felt the excursion going wild at very low frequencies, and although I did not measure that, I know now it will be the same.

Large deep orchestra hits ? the very same I bet you.

So, while this latter track gave me super joy and the others were merely about "base drum" as such, those others made me feel a bit sick in the stomache. Because indeed, that now works (Mani !).


Now, because of the superb rendition, I have been thinking many times before that this "known" track should be uploaded to somewhere, so people can have a reference of what can be achieved these days. I never did that because the drumming is really too poor (that was also me). This track though ... hey, I could sell it !
Whether especially this track works out for you I can't tell. It's 15 minutes long and all I know is that it's full of cymbals just the same. They should work out ...
Now I must find some space with a for you high download speed. DropBox perhaps. It's 1GB in WAV.

One more thing before you all start to think too much of me :
This is nothing about wild drumming or never heard roffles (I wouldn't know how to). But what I notice (remember, I never heard it myself before) is some kind of perfect timing at a strange means of operating the drumkit which matches some kind of adrenaline which must have been in me, that envoked by what I must have heard myself in that (14x6x4m) room. So what I perceive of it is a rythm on the ... ambience ? Go with the flow or something.

Brrr
Peter

[juanpmar]

A nice sample with an amazing deep bass is
http://www.amazon.fr/Fabuleuse-Histoire-Swing-Michel-Jonasz/dp/B000F39MI8/ref=ntt_mus_ep_dpi_7

Disque 2 - tune 2

Btw, a more normal album you all might have (outside of ambient I mean) is Zappa - The Yellow Shark. Try track 04;
The hits you hear in there (for sure) are all 32Hz. Not amazingly low either,  but notice that the 32Hz in this track is the loudest of the whole spectrum. So key is here that this 32Hz should blast in the room, knowing that the second loudest instrument in there is the oboe + clarinet (I think) and they play mainly at 400Hz).
With my previous setup this played as well - perceivedbly - because the 32Hz sound is square and its harmonics are easily heard and the more airy sound of the fundamental kept working well because it is so loud. I'd say this is not "room" reveraration we hear in his track which already can be seen in the FFT by the very straight and solitude fundamental.

Happy listening !
Peter

Peter, The Yellow Shark (Frank Zappa) is one of the best recordings I remember and talking about ambience this album transmits the stage (and the audience) in an impressive way. Another album, although not a live recording, that has really a deep bass is "Deeper" from Pete Belasco, in the track 2 (Deeper) the bass is hard to reproduce correctly but if your woofer can you´ll get a very very deep bass (in some notes) perhaps down to the 20Hz or even lower. I know that here we are talking about bass and ambience but also, I guess, about the capability of the woofer to reproduce the bass frequencies correctly.

Please share that recording with the drums!

Juan

[GerardA]

Yes Peter, please share the recording, because I  don't get what it is your saying about it!
The only thing that resonates in my mind while reading your story is maybe the walls and floor resonate to make this low frequency?
Question, is there low frequency ambience when the musical instruments don't go so low?

[PeterSt]

Gerard and all,

I realize that I - with my ever (indeed) controversial ideas and approaches - will be hard to follow. Of course this is difficult to begin with because this is audio, but my theories of how things really work expand and expand, while no one "white paper" exist to find the proper base (of those ideas). Fact is : it is always about using that just different/new "environment" so it is pioneering in the first place. This latter says I can easily be wrong on a couple of things, but it for sure tells that nothing will be in school books.
And it *really* is difficult, because those owning a NOS1 and thus know the comparison with their former ($$$$$) DAC, have that base which I take for granted but which also *is* that base. Or prerequisite if you want. And you (Gerard) lack that base, like so many others of course. So how to understand even the slightest ?

But I'm sure that eventually we will get there.

We will start with that recording, which also is as controversial as can be. This time because "how would I be able to outbetter the whole universe". Well, you will see I did once I managed to upload it to somewhere, but it is not about that really. What it is about is that this is so outrageously better and that it proves that our chains are THUS capable. I mean, if you listen to this you won't need any new DAC or speakers or whatever. You will see that you need new recordings.
Which sadly can't happen, so you need a new DAC etc. after all. It really is ridiculous.

Peter

[acg]

Yes Peter, please share your drum track. 

And I am with you on the recording quality thing.  It annoys me that some of my favourite music sounds so ordinary.


Anthony

[PeterSt]

Let's not forget what the intention of this topic is :

How ambience emerges. And really, I started to wonder myself when Bert found 4 seconds enough for that 09 track mentioned earlier. And in aftermath, he really could have heard that 24Hz (?? - must check it !) organ. Unless it was the sound from the right speaker which to me sounds like opening some organ cover, but probably is just the organ player opening a register or something. Mind you, this is not about audience voices.

So what actually should be by definition of ambience ?

This was not covered in this topic yet, but this is foremost NOT about people talking or coughing or moving etc. This is how I referred earlier to it NOT being stupid Pawnshop stuff. That *is* about talking. Sure, it could be named "ambience" as such, and again sure, some systems may show this better than others, but the pawnshop example os too excaggerated.

And so I say - at least for this topic - that there's a mere technical thing that creates ambience, but it is about the room response. And mind you, the room of the recording.

So, via-via-via I am now as far that the ambience of the recording space by far overrules the response of my own playback room. And this was due to come with all my ever talking about no standing waves etc. etc.
To really understand this, one must just experience the crazy "possibility" of what mainly the low frequencies can "do" in my room, which already to myself seem impossible. I can't explain this by words, although yesterday I tried (by means of the average sound pressure not changing (kept at zero)).

It is all a very large bag of working-together phenomena and it needs technical explanations (with actually the best base knowledge which I may not have) to explain what theoretically can happen in your listening rooms too.
But as I said, I think we can get there.

[PeterSt]

So we can get there ...

The only thing that resonates in my mind while reading your story is maybe the walls and floor resonate to make this low frequency?

Gerard, this is a very good one and at least this is what I can still see happening in my own listening room. So the answer is actually Yes. It is not the only reason more low frequencies emerge, and it may not be a profound one, but it sure is partly a key to what happens.

When I have the measurement by microphone set up and no music is playing, it is totally easy to see that even when I try to walk in the room with no audible foot steps, there's a ~50Hz fairly high SPL measured. This is way under music playing levels, but fact is it is there. What does this mean ? well, I'd say that music itself hammering on to the floor will do similar, if not way more. Remember, I walk as light footed as possible, and still the most easy to see. So what will the music do ? Or the speaker itself being on that floor ? Most probably more (speaker itself way less I'd say).
(btw, when this hous was designed, in design it contained chains attached to the sealing of the floor above, and my speakers would be connected to those chains ... just saying (but that never happened))

But I don't see any of this when music plays (through FFT and e.g. reoccurring common denominator) frequencies. Still it has to be there, and this is "ambience". It is my room.

While I in the previous post just said that the ambience of the recording space overwhelmes the response of my room, this can be explained like this I think :

Take for example that drumming recording; I already prepared a text for it (going along with the upload) and it tells that at such and so fairly loud level you will be playing at 10dB under reality levels. That's a good thing, because cymbals play at 110dB in reality and you don't want that. But what it means is that in reality that drumkit is hitting with 10dB more at that same floor (would the drum kit be in my listening room) and that thus 10dB more hammering on that foor (but also walls etc. of course). So what creates the ambience ? obviously the live recording (room !).

Remember, this all takes as a prerequisite that the sound waves are quite undistorted in the first place and that e.g no ringing is allowed from D/A converters. Why ? well, when that happens there's already a sort of added waves ("standing waves") springing from the speaker, and certain frequencies overwhelm others to begin with, and for example the base drum can now sound louder than the cymbals AT PLAYBACK. Next that thus hammers unevenly more on my floor, and there you go ... the whole reasoning immediately fails.
(and I could chain together so many more elements for failure)

But Gerard, although I started this with quoting your text, I don't think this is the answer to it ...

[PeterSt]

Question, is there low frequency ambience when the musical instruments don't go so low?

I think this has two possible answers;

First, cough in a church. Doesn't that hall back to us in a lower frequency than what sprung from our coughing mouth ? I think it does. I don't think the brick walls will vibrate much of our coughing. So something else plays a role. And this is in the second answer :

Specifically referring to my (empirically !) found LF happening only when more than one (drumming) tom was used at the same time, this is about two frequencies which superimpose on eachother and the result is ... a lower frequency. Similar can happen with bouncing waves of the same frequency, but this is more difficult to explain, especially because it needs good graphical simulation of it. But that aside, look here (the best I could find in 15 minutes of time) :

http://www.acs.psu.edu/drussell/demos/superposition/superposition.html

Scroll to the bottom where you see "beats" explained;
Look at the top grey sine as one of the toms, and the line under that as the other, and both do not produce the same frequency. The resulting sound wave is the bottom blue wave.
Now, just look how fast the frequency of the two top waves change and compare that with the max amplitudes of the bottom wave passing by. Easy to count, and the resulting wave is 10 times slower than the original either two. So, my toms which play at 60Hz or so (try to look back in my mind what I saw yestyerday), now play at 6Hz. Rumble ! But especially rumble because of how this "beat" evolves. So, the blue line actually has a resulting frequency that is similar (in between) the two toms, but the level (max amplitude) changes at this much lower frequency.

Are we getting somewhere now ?


PS: If you think "ringing" I briefly touched above, on that simulation page you will also find some "data" on what happens with that. But the example does not suit it really (would be the second simulation) because both original waves should follow eachother at some distance (and here one stands still). But you may get the idea.

PPS: Don't stare at the picture below. Instead click the link more above !

[Leo]

I think similar things happen when you tune a bass guitar for instance. When the two strings (one open , one 5th fret) are not exactly in tune you get a very low frequency of the difference. In former days bassplayers held the flame of a lighter in front of the speaker when tuning. If not in tune the flame would wobble with this very low frequency and you turned the peg untill the flame stood still....

[Jud]

Question, is there low frequency ambience when the musical instruments don't go so low?

I think this has two possible answers;

First, caugh in a church. Doesn't that hall back to us in a lower frequency than what sprung from our caughing mouth ? I think it does. I don't think the brick walls will vibrate much of our caughing. So something else plays a role. And this is in the second answer :

Specifically referring to my (empirically !) found LF happening only when more than one (drumming) tom was used at the same time, this is about two frequencies which superimpose on eachother and the result is ... a lower frequency. Similar can happen with bouncing waves of the same frequency, but this is more difficult to explain, especially because it needs good graphical simulation of it. But that aside, look here (the best I could find in 15 minutes of time) :

http://www.acs.psu.edu/drussell/demos/superposition/superposition.html

Scroll to the bottom where you see "beats" explained;
Look at the top grey sine as one of the toms, and the line under that as the other, and both do not produce the same frequency. The resulting sound wave is the bottom blue wave.
Now, just look how fast the frequency of the two top waves change and compare that with the max amplitudes of the bottom wave passing by. Easy to count, and the resulting wave is 10 times slower than the original either two. So, my toms which play at 60Hz or so (try to look back in my mind what I saw yestyerday), now play at 6Hz. Rumble ! But especially rumble because of how this "beat" evolves. So, the blue line actually has a resulting frequency that is similar (in between) the two toms, but the level (max amplitude) changes at this much lower frequency.

Saw you mention 38Hz twice, and mention a couple of tracks sounding the same - I wonder if one possibility is your room and how what you describe above would work within it.  Same room dimensions, same frequency evolving from the superpositions?

[PeterSt]

Haha Jud, I thought about that too of course. But no.
My room length of 12M implies 28.67 Hz which is what I cam exactly measure. And if that bothers me I open a door.

and mention a couple of tracks sounding the same

I don't think I said that. What I did say is that when two very different albums put up a nice sine of the same low frequency, they both sound exactly the same, which is of course which should happen.
And next : when that sine would be subject to distortion and harmonics spring of it because of that, nothing sounds the same because the harmonics play in the same space as many other instruments. With any form of not-sine with a LF fundamental, same thing.

Actually this is very easy to understand but it is NOT easy at all to comprehend. So, elsewhere I said that I spent a fairly enormous amount of time in "discovering" that these were just the nice sine frequencies I perceived because it really looked like a speaker property. So, most obvious would be "sounds the same thus speaker colors". But the way much simpler answer is "is the same thus sounds the same".
We are just not used to this at all. And to keep in mind (I said this a couple of times too) : Those low frequencies always play alone. Not necessarily of course, but when I was to make a nice base line playing well under 40Hz I sure would not do that with two different (synth) "voices" and I also wouldn't use chords. I mean, it is difficult enough as it is to produce something audible in that region, so it has to be simple.
Anyway, of what I perceive this just is always so.
And thus again : when a simple sine is put up, it's on its own there, and should sound the same in any track putting up that sine of the same frequency.

Additionally, let's not forget that hardly anything can produce real sines but if so we would recognize it as an instrument instantly (certain organ pipes, flutes). So see ? we do recognize it after all. So why not LF synth produces sines.
I say it again (and again) : I never heard that LF (way interesting) stuff in there. It's two new dimensions at the same time (one for it being so audible and one for it is meant to be the melody most often).

Peter

[PeterSt]

Sorry about the caughing which must be coughing of course. Dunno why my perception of this was different in the morning than now in the afternoon ...

[CoenP]

Insights from the (former) "golden age" of audio.

Regards,  Coen

[PeterSt]

Yea, a bit old that is. Looks like pre-synth area.
Also, lowest organ is 16cps. But only 3 or so exist on the globe.

Anyway, still a nice reference.
Peter

[PeterSt]

And in aftermath, he really could have heard that 24Hz (?? - must check it !) organ.

So I checked it yesterday. 32Hz it is.
Funny though, the main two lower keyed organ pipes heard are this 32Hz and 66Hz (this should be the audible one which regularly is in the track). Not 64Hz.

But at watching the FFT I noticed something very interesting;
At 4:19 up to 4:29 there is a most clear 22Hz (inaudible for me);
When I was watching this yesterday I couldn't find much of an explanation. Later however, it sprung to my mind that this must have been such "beating" I have been talking about.
Too difficult for me to really see (and calculate) which of the other organ tones (chords are played there) would incur for this, but it sure must be that.

In the past I have been reading (or examining) about "sub harmonics". At least back then it was recognized as non-existent. But possibly it depends on how this is looked at, because a normal fundamental is not able to. However, and in my view, as soon as an instruments exhibits more than one frequency and those harmonics as such are not a 2nd, 3rd, etc. related harmonic, such an instrument will do it by itself. Just a thought : like a violin plays a normal frequency, but the fast "stuttering" of the resin over the string would be a very different frequency.

Peter

[PeterSt]

Ambience, rumble or just music ?

With my own example of the "Beating" in my mind, I have been watching the FFTs during music playback the past two days - now with the emphasis on this happening;

I can tell you now, it is actually very hard to find music where the sub-low (say under 30Hz where clearly no instruments are playing at all) is not present. So it is there always and with some music you can clearly see from what it (instruments etc.) originates. Also, experience from both listening and looking helps being able to hear it clearly.

I must tell you that I maybe even more explicitly started to watch for it, where in my observation it could not be "ambience" as how I described it. I mean, no recording room phenomena. Still gives an "ambience" presence, for its sheer more air-filled (or air based) playback. For example, once you feel air pressure on the stomache on some music beat, I may take I for granted that somehow this instrument creates this air pressure by means of its audible tone of the moment. You would too (assumed the fair amount of good sub low). However, once you watch the FFT at the same time, you can clearly see that it's the "umpf" at the real low frequencies which really perform that stomache punch. Not visible ? then no punch either.

Something else I saw now, is that this sub-low waves - and which don't need to be punches only - can go straight to 10Hz just as well (10Hz is the measurement limit for the FFT I use here). With "straight" I mean "all the way", because straight in level is not so (the Orelino is set to roll off under 18Hz). So, it is worse than I originally thought. Or more important - also good.

Generally - and when not about explicit low frequency sounds (like mentioned ambient music does it) - as soon as a more mass starts to play together, the sub low "rumble" emerges. So if only this "Beating" is allowed to be a directive for how two frequencies create the lower ones, it can't even happen otherwise. To what degree (for low frequency) this happens, should totally depend on the "offset" of the two (or many more) other frequencies playing. So, the less offset (the more close to eachother) the lower the resulting frequency of the beat will be. Thus, thinking about my given simulation example, when a 1000Hz and a 1001Hz would be playing, once in the 1000 (999 ?) wave cycles the beat would be at its maximum, and the frequency - remember, "modulated" on the 1000 and 1001, would be 1Hz. That this in this case would be a very slow moving up/down for level is something else and for that reason it will not be a clear peak (level drops from max to zero and back in one second (= 1000Hz per second base).

A next thing to notice (or maybe I have said that already) is that the max level of such a beat is the accumulated level of the both frequencies when they both meet at their tops. So when the level of the both frequencies would be at 60dB, the both together would form that low frequency at 66dB or two times as loud. This, while no musician created it like that. Now, this happens all over when coincidentally two instruments play the same frequency in the same phase so we are used to that. But with those ultra low frequencies we are not and/but it is thus easy to create the "effect" in pronounced form. In the mean time though, our subwoofers must be able to cope with this additional excursion (no designer weighed in), which they most probably will be able to, BUT will create distortion;

And now it becomes complicated because the distortion coming from that (just 2nd and 3rd and so on) are the most audible. So for example, when a 25Hz "rumble" is in order - and this is just audible as a frequency (for me it is), the 50Hz harmonic springing from it because the 25Hz being on a fairly high level, is always way way (way !) more audible. So, the whole lot can easily produce 50Hz which is nowhere in the original.

More about this later (if someone is interested anyway).

[pedal]

Peter,

Last time, did you get this title: Jøkleba LIVE. Its free jazz With awesome SQ. Note some old fashion synth generated looow frequency notes.

[PeterSt]

Ambience, rumble, music or just distortion ?

A couple of days ago I received an email from someone who I consider quite knowledgable in the field, and he pointed out to me that my perceived most strong bass most probably is harmonic distortion after all. Of course I refuse(d) to believe that, but it brought me the idea of "just measuring would be way more convincing than listening only". So I sat down to do just that.

Meanwhile the person told me that woofers in general easily allow for 7% of harmonic distortion.
I was shocked, but recognized that I saw some 0.1% figure somewhere when the microphone was up to some other task and that "I better not officially measure THD to begin with". Not being in denial, but merely thinking that measuring a loudspeaker this way makes no sense or is of no use. Otherwise, what to do about it when not-so-good after the the drivers have been selected (on whatever spec beyond me). It is just a given fact.

Not so (at all actually) when someone like me is tuning a speaker into its sub-low limits and that for an open baffle which would be more difficult to begin with.

So I started out with Google in order to find out specs for woofers or what they would be allowed for THD;
What did I find ? NOTHING. Ah, that was odd, but maybe just a good thing. Ok, I could find specs for woofers which tell about nice low figures, but they talk about some agreed low Wattage fed to them. Or Voltage, whatever. Useless (to me).
I found this though : http://www.audioholics.com/loudspeaker-design/2010-subwoofer-shootout/2010-subwoofer-shootout and the main picture in there is this one :

The red line indicates an official "spec" to what subwoofers are allowed to exhibit for harmonic distortion.

Although this is about subwoofers and not really woofers as such, for me it is the thing to deal with, because aren't we talking about subwoofers ?
So, if you look at the test signal there and see it is 20Hz, the red line tells that the first harmonic (40Hz) is allowed to be at not more than -10dB. If more, then the subwoofer is no good.
N.b.: I ran into ABX tests where similarly was examined in a group of people, and the results were that nobody could hear a difference in those lower registers anyway.
In advance of how this post will end : go figure.
Anyway, a subwoofer manufacturer should produce his product in compliance to this graph, and when it does it can "officially" go out. Of course, many do better, but this is about my quest to how actually others are performing, while I scream about a couple of things and whether that is justified (audible I say Yes, but what about some figures and what will they mean to you, you too not really knowing what would be normal and what would be in excess (either direction)).

So what a speaker driver is about (amonst other things) is that it should not produce too much HD (harmonic distortion) and we know that when excursion gets higher HD will increase. Also : when the SPL to be produced gets higher, excursion will be more. And : When the frequency to produce gets lower for the same to be produced SPL, excursion gets higher. So all is related especially when we try to achieve the lowest frequencies at workable SPLs for our music.

Now first the for me foremost important thing, and I see no writing about it anywhere :
When we talk subwoofers, we talk by sort of principle of frequencies we can not hear. Of course, a subwoofer can go higher (at will of the manufacture and which for sure is the case with our Orelino here), but a subwoofer is no subwoofer when it can't produce, say, 22Hz at reasonable SPL and which 22Hz is inaudible to most (to me it is inaudible). But, way beyond that just the same, like my former SVS Subwoofers who do 12Hz (I forgot at how many "dB down" but alas).
So, when producing inaudible frequencies this emerges as air pressure changes we will perceive and it gives additional layers of whatever we are listening to.

How shocking it was for me when I found that in general (frequency point) no less than 22dB down the 2nd harmonic has to be in order to let the fundamental do its inaudible job ... So, no single way that picture above resembles anything that can be good for music. Effects maybe, but no wind effects. So what happens ?
(it is too easy to even think about once you know how it works)

Suppose we have 30Hz. Sounds nice. Then at the same SPL we create a 25Hz. Hey, it sounds higher in frequency ? Hmm ...
To understand better we go more down : We have 20Hz and it should be silent. Why ? well, we can't hear it as such. Not silent ? ah, then you hear the 2nd harmonic which is 40Hz. Easliy audible ! And so with that 25Hz sounding higher than 30Hz, what we'll perceive is HD and it plays at 50Hz.

Now let me tell you, when I'd sustain that red line in the picture and wich actually tells that any 2nd harmonic is allowed to be 10dB down before we'd perceive it as distortion ... NO WAY. When I would allow for 10% HD on that 20Hz tone, a most blasting 40Hz would be audible.
And again, it is so easy : When some frequency (like 20Hz) is not to produce any sound, how high in level would we think it's 2nd harmonic (like at the very audible 40Hz) is allowed to be ? Hey, that's actually nothing man !


With a fairly still good audible 25Hz things become different, because now it is about how the 2nd harmonic will be perceived louder by us than the 25Hz. Well, that is not so much. 30Hz is the most well audible by all of us, so here we indeed have more headroom. Now it really becomes a matter of how we can a. hear the 30Hz be distorted (this is way difficult I think) but b. how the 60Hz 2nd will start to be profound over the 30Hz. So here YMMV (since I did not sort out the exact figures for this, but which also is not necessary, which you will hopefully grasp by the below text.


What I did in the end was not so much testing the HD levels but merely tuning all so that no audible HD tones could be heard. This is subjective, but measurements support it to some degree, so I used that foremost.
What I did, I did because of the process of "functionality" and this was as follows :

Find an acceptable SPL for my personal listening levels. This was 86dB. So, just measured from normal music playing. 86dBSPL would be sufficient (but carefully read the below topics as well).

Look per frequency what the THD is; Important notice : the general level of THD while spades of headroom on the SPL was still available, is 0.3% (this is invisible at the in-room ambient noise levels of -90dB through microphone).

At some point at going downwards in the frequency spectrum the THD starts to grow. I forgot where, but this is not important. Important is where it grows so much that the SPL for that frequency apparently is too high. What came from this is that from under 30HZ downwards the SPL had to be squeezed. The limit for this I took was a general 3% because more than that is audible, but it includes some headroom so I actually followed 2%. So, at no frequency under 30Hz I allowed more than 2% THD. This is all the way down to 10Hz.
So for example, all the way down to 10Hz I did not allow myself to hear a single thing coming from the speakers, were it for the frequencies under 23Hz which I can not hear anyway, and thus *should not hear*.

The result of this is that a linear decreasing slope of 9dB is needed from 29Hz to 18Hz, which latter 18Hz was rated as " the -3dB level". Officially this now should read as "18Hz at -12dB".

This all explicitly assumes that while music in normal frequencies play at 86dB, the lowest frequencies would play at the same level. It is my idea that this is not much the case (I just see that when music is playing). However, when indeed that does not happen but say at -10dB instead, my "set" 86dB would be 96dB and all would still be OK.
Small notice : this was before I realized that "Beating" should theoretically imply higher levels from the normally playing frequencies, ad explained per previous post. Still I just see that it is the most rare that the lowest frequencies go all the way up in level. So I think I'm good with this strategy.

Speaking about a commercial speaker, the net result would be :
- That when you play at 86dBSPL - which for me would be suffecient in my 12x8x3m room - there's the guarantee that no audible distortions come form whatever crazy bass up to even 10Hz and lower.
- That most will have a smaller room, and that the smaller the room, the more perceived SPL in the listening seat will be there at the 86dBSPL at 1 meter (read : for most the perceived output can be significant higher than what I think is enough).
- That I perceived the total image of the music to be more clean; couldn't hear any distortion previously explicitly, but it should have been there.
- That by empirical finding whatever distortion has been there before does not imply these crazy basses; they are still there as they were.
- That ... it net does not work for the better.

Oh.
So, the perceived cleanness - which might be a placebo in the first place - at least causes the "air pressure" output to be less, and I sure perceive that. Maybe that is too much anyway, but I got used to it and now I am not sure this is net for the better.

All could be much moot because at e.g. 30Hz it is way tough to play too loud so 2nd (and beyond) harmonics are audible. Same counts for the THD % which is only 1.1% at louder than the calibration level already and with the knowledge that  it was 0.8% at 6dB less output. So a very slow increase there, while in this area possibly the -10dB is allowed from the red line in the graph (I did not test that because way too loud). This 1.1% probably was at -20dB or so. Thus spades of headroom here.
And to keep in mind : the lot gets only really critical when actually almost no sound is to be heard and this non audibility fastly increases when going down from 29Hz.

The above said, not much plays explcitly in that area anyway. The reason is obvious : we can't hear it. That other thing, the "ambience" or what name we really should give it, is a far greater problem, once we allow our speakers to play in that area anyway. So, don't allow that (say cut at 27Hz) and there can't be a problem. In the mean time though, this "ambience" won't be there and this is what I can notice right away.

Of course, there's all kind of playground between my -9dB drop and 0dB drop which is related to the necessary SPL as explained. The smaller the room, the better it goes without distortion. At the far end this extends to : the more small the room, the lower we can go undistorted. Like 17Hz or 16Hz.
Whether this brings more ? My findings so far say Yes. The lower the better, because it is all in there.

Btw and FYI, with only one paramater in the DSP settings this slope can be set with full justification/consistency of further everything (example : the crossover should not change).

Hope this is helpful or even interesting ...
Peter

[PeterSt]

An additional remark about my drumming track :

Forget it;
I have to assume that at this moment nobody is able to perceive that "ambience" or low, say, rumble that I perceive myself. And the point is : with only that -9dB slope from my previous post it already does not work anymore, at all.

Actually it is totally stupid if you recall me telling about my perfect timing and "go with the flow" in warm water baths and what not; Without being in that warm water bath, my timing is nowhere. It is just not true. But being in the midst of that "rumble", yes, then I can do it. Not that I can do it, but then it is perceived like that.

So I don't know whether "timing" as such is now a new subject in the realm of "how can ... ?" but to me it definitely looks like wrong timing can be masked with a sufficient amount of air under all. Things just sound so nicely soft, while the first thing I noticed yesterday at retrying the track with the -9dB slope in, is that all is precise and hard. Precise eh ? yea, that maybe, but it also tells when things are precisely off beat and all.

Cymbals are still of extreme quality, but the drumming is too poor to put up, really.

[PeterSt]

PS on the larger previous topic : Apologies for all the typos which were in there at first; I tried to remove them now.

Peter

[PeterSt]

Jøkleba LIVE. Its free jazz With awesome SQ. Note some old fashion synth generated looow frequency notes.

Oh yes ! So first there's the more heavy drum with its so nice spread from its peak at 48Hz to the to the left and right (same slope) which creates that ambient sound full with air and next there's indeed what must be a synth with its lowest notes at 18Hz. Notice though that from the latter you'll only perceive its sqaure based higher harmonics but in my view the perceived deep warmth again is this 18Hz.

Maybe I should tell that you can be considered to have a real subwoofer ? I mean, a sufficient amount of drivers in there, but I forgot the size and amount (per side).

Btw a message from Ciska here :
Gry won't be happy with this album. Nor does Ciska. But didn't we know that ...

Best regards to you guys,
Peter

[PeterSt]

I just tried to find an example with at least "ambience" from the by now far past. After two Pink Floyd attempts which failed and which I actually just tried (Meddle and Obscured by Clouds) I dug in my mind and envisioned Emerson Lake and Palmer. Pictures at an Exhibition ? nah, ever described by me on this forum as "the guys never heard it themselves this way", I merely thought of Tarkus of having some "fat" sound. LP era.

Ha, spot on ! But but but, strange thing ...
I have the MFSL and noticed that it normalized from -29.5dBFS to -28dBFS. Can't be good. So, tried the the "normal" version I also have, and that normalized to -21dBFS. Hey, that looks way better (IOW less compressed). So, MFSL ? hmm ...

Anyway, that normal one indeed has that super fat flavour I recall, and it's only that it rolls off beyond 30Hz quite fast. For vinyl perhaps ? So rolled off so not too much "DC" (square) is not to be on there ? Perhaps.
Btw, all the LF I see is "ambience". So no clear very low frequencies (32Hz is the lowest I see from some (simulated ?) church organ).

Do notice : The "normal" version has a first 20 minute track named "Tarkus", while the MSFL has 7 or so indivudual tracks for that. Is it really the same ? not even sure. I played half of both versions.

On to the MFSL ... hey ! Straight to 20Hz ?!? (and gone right after that). Ok, now what does MSFL actually stand for ? hmm ...
(notice that the album is from 1971 in the first place).

Immediately I notice that the MFSL is full of air. Ok, clear.
Or ?
Or maybe not, because it sounds sibilant to me. More refined but sibilant. Nasty actually.
Anyway, these both versions sure contain the "ambience" as such and all my selection criterium was : fat sound of the past.

Next up will be Triumvirat. Same idea. I guess I can't be correct on this again (heck, this is long ago !).

[CoenP]

Just to support the long post about audibility of the extreme LF (sub) I post the famous Fletcher Munson "equal loudness" curves. The slope to the start of the curves (starting at 20 Hz) is very steep down , that means you can have only very little distortion before it appears above the audibility threshold. So a 89dB sound pressure 20 Hz tone will produce a second harmonic of 40 Hz that will be audible at a level of about 50 dB pressure. That is about 1% (-39dB) max for the second, but the third and fouth are even more important (38 or 30db threshold or less than 0.1%). The audibility of these is speculative though since they could well be masked by noise or music.

The classic way to reduce distortion is to reduce the motion of the bassdrivers (or linearise them by motion feedback). Usually this means more woofer surface and/or horn loading which has a practical limit of 35 hz is a domestic environment.

Anyway it is great to learn about the Bass of the Orelinos which does something special to the listening experience even with the distortions in place.
Please keep posting your progress!

Regards, Coen

[PeterSt]

Well Coen, I really start to wonder whether there is anything you don't know (about) - all seen through my own glasses of course, which can be mistified at times. Just saying.

Btw, I think that picture is not the official Fletcher Munson curves but rather the AES 2003 whatever representative. See here for the original F-M curves.

Still you don't know everything and amongst that is that the Orelino plays through curves which represent the F-M curves. well, almost, see text more below.
What you and everybody especially don't know is that my whole raving about this speaker's bass is all about the contradiction when these curves are taken as a lead. So, all you see me writing has as underlaying subject these curves, which are not correct for the bass at all. In other words, I feel supported by this "strange" contradiction because I am achieving things which are not recognized in the world so to speak and therefore "I am into something for sure". Again, through my own glasses. Ok, ears.

First this one :

So a 89dB sound pressure 20 Hz tone will produce a second harmonic of 40 Hz that will be audible at a level of about 50 dB pressure.

Nah, not quite. This one is simpler and I told about it in that larger post : 20Hz is just not audible. This is not related to any F-M curves etc., it just is not audible because our auditory system will not produce interpretable sound as such. It's wind. Also notice above F-M curves, which do not show 20Hz at all (starts at ~25Hz). In your picture it starts at 20Hz, but that doesn't make sense to begin with.
(Side note : who am I to say this ? well, read on.)
Anyway, when a frequency is not audible officially (23Hz and under for me), *any* harmonic distortion popping up at *any* level which makes it audible is too much. So, say that you can perceive a 40Hz at 70dB under your normal listening levels, then the 2nd harmonic of 20Hz will be audible when at 70dB down. So, not 20dB, not 40, not 50, just anything which makes it audible. For the inaudible fundamentals this is the most easy to check, and for the audible ones this is more difficult. But in general : when you go down step by step and suddenly the next step sounds as high or higher, you will notice the distortion by that means. This is also profound over the distortion in the fundamental. So, easy.
This is very different from putting up even 25Hz where you are to judge whether this distorts. So with a good absolute hearing you might be able to, but with less good you may not recognize that the net pitch got somewhat higher because it is mixed with 50Hz. And then to think that 25Hz is a most easy example actually, because already so less audible. But with 70Hz ? Good luck. Still though, when going from 72 to 71, to 70 it is the most easy to hear when 70 sounds suddenly higher than 71. Thus, do it like that - easy.

Although there is some sense in relating the F-M curves to harmonic distortion (HD) I don't think it is a real lead for this. But *if* there's a lead or base for how we can perceive HD it is about this (look at my picture now and just take the bottom curve for example) :
When we are to perceive 110Hz at a certain level, we will perceive 1000Hz an 11dB louder. Or, when we want to perceive 90Hz at a certain level, 1000Hz will sound 20dB louder to us.
(look for the more realistic comparison at e.g. the 80dB curve)
So all this says really is that once we want to perceive that 90Hz in well fashion, we must be careful about its 10th harmonic because at whatever level that comes forward, we perceive it 20dB louder than any FFT shows us.

But really, I only tried to reason out something which is no subject at all. It is maybe, but it is completely overwhelmed by other findings.
So, what actually happened here while "tuning" this speaker ?

Look at the 70dB curve;
Just by listening and after being satisfied, to my surprise I found that I am following this curve exactly. Mind the 70dB which is listening levels though on the low side. But anyway this is the best representative for the curves I created - so just to give the idea.
Especially because I wasn't aware of these F-M curves (although I had seen them ever back), I was shocked to find this prefect match. In other words, this could not be a coincidence.

Because this can not be a coincidence, everything *not* matching those curves should be explainable, right ?
And this is how I actually started the whole "bass" subject, because the low end of the curves do not match AT ALL. In other words, when you see me writing about super bass, up into the near inaudible levels (because of frequency we can't interpret anymore, for me 23Hz !), there is no single way these F-M curves represent what I perceive from this speaker.

When I was to tune the lot under 1000Hz like you see in the curves (those 2003 curves even far worse) then windows would go out because of bass alone. So, looking at that 70dB curve and assumed I would be playing at 70dPSPL, then 30Hz would come out something like 17-18dB more. So, music above 1000Hz plays at 70dB and when there's 30Hz it plays at a sheer 88dB. True, this is what our SPL meters would say  but this is also totally audible and I would die of too much bass.

It may be complicated to follow, but with measurement it would come down literally to tuning all for SPL levels, and that 30Hz should output 18dB more than 1000Hz and when so we would perceive the both equally. That's what the F-M curves say, and that is what they are for (but also investigate the Phon unit (mentioned in Coen's picture) which does about the same).

So completely contrary to the F-M curves (let alone the 2003 version) my curves are just completely straight; they are straight from 600 Hz downwards. And then STILL I report "concert level bass". And, of course, any measurement shows equally loud levels from horn (up from 280Hz) and woofers. But also, my former speaker did that too. And no concert level bass at all.

So you see ? this is how I end up raving with a "what is actually going on ?!" and this is how I try to explain that through the various posts. But this is also how I try to squeeze out similar from you all, where a perceived equally good 15"er (could be my previous, could be Juan's) - rated to 27Hz flat at least for my own former and measured by myself - does not make a 32Hz organ pipe come through. Even not at all when supported by "official" subwoofers.
So I could go through all that reasoning again, but I already did that (tried at least), because indeed *something* has to be going on really.

These F-M curves, but maybe more that 2003 version which is worse, should depict official science. Well, am I not always going against that, and would it not be the first time that empirical finding learns a few things (after being ignorant about any so-called science in the first place) to next meeting the necessity to come up with some explanations. Say that is me myself and I.

So I tried to find out under what conditions both the F-M curves and the 2003 version where derived, and all I can say is that the F-M curves emerged through headphones which seems to be for the better (as claimed) while the 2003 ... I am not sure. The only difference I really see is that this is all through a mere special open baffle setup which can better be named "horn" and that both designs will at least contribute to less harmonic distortion at a. the higher SPL and b. for the lower frequencies (see yesterday's post).

In the mean time I (thus) have been working on proving whether it all could be about distortion after all, and this is not the case.
All I can say at this moment, is that when we would try to derive those curves from my former speaker system, I probably would come to similar curves in the bass area. So, I guess I would sure be able to perceive those 32Hz pipes easily, if only first the bass would be pumped up by 10dB or whatever, but, which can not work because no speaker would allow for that without first heavily distort (even more). Otherwise I think no speaker designer will deliver his speakers with the bass pumped up by 10dB anyway (and I mean seen through SPL measurement) and thus we all *think* that the F-M curves apply.

But all what happened (in my view) is that they were obtained through means which are not today's best (loudspeaker) means. At least I see that this is so through the Orelino speaker and all I continuously try is to debunk my own findings. But so far I can not succeed.

Usually this means more woofer surface and/or horn loading which has a practical limit of 35 hz is a domestic environment.

Coen, what is this 35Hz based upon ?

Regards,
Peter

[Scroobius]

Peter - this is very interesting stuff thanks for posting. I thought the original FM curves had been later found to be incorrect due to (possibly) measurement errors(?) Anyway it all brings back memories of that "loudness" button I used to have on my first amplifier.

It was not that long ago that I put a 20Hz (and 30 and 40 etc up to a few hundred) test tones through my ANE's and was surprised at the healthy output at 20Hz and also some surprise that it seemed slightly higher output than at 30 and 40 Hz. So now I know - I was not listening to 20Hz at all. Just shows how easy it is to get things completely wrong in this hobby.

Paul

[christoffe]

For information

http://www.audiomatica.com/wp/wp-content/uploads/2012/03/appnote_007.pdf

[PeterSt]

Joachim - Thank you. To me this shows nothing different than that picture in my yesterday's post and that indeed an official loudspeaker measurement tool (CLIO) contains an as official test for loudspeaker distortion.
In the mean time I understand less and less of it all.

All I derive from it (all) is that my standards are (way) too high.
Well, so be it.

Peter

[PeterSt]

One other thing :

What I also see from measurements like these (throughout) is fairly excessive 3rd harmonic distortion. Often higher than the 2nd. FWIW : I don't measure any 3rd here. Nothing.

With the quote of "3rd is more important to us", I (or we all) may wonder what that's really worth. To me ? nothing much exciting. But why ?

Any 3rd harmonic is about "square" distortion which in itself means that it is about the theoretically necessary infinite amount of frequency to represent that. So yes, looked at it from this angle, any 3rd will imply an infinite number of odd harmonics, knowing that in the end something won't be able to cope. Of course this is the same when any instrument puts out a more square tone, but let's say that this belongs to the instrument and only needs more sampling rate (to represent that high frequency well). And maybe superfluously : only when indeed infinite frequency is available a square can be a real square.
Anyway, when a 3rd expresses while not any square is in the music itself, you will perceive that as infite harmonics (all thus odd). Could be sibilant.

Why do I not measure even one 3rd (and thus also not beyond) ? I don't know, but it should be about cabinet reflections (no cabinet there) and otherwise room reflections (no significant room reflections there, derived from no standing waves there). In addition : I think that any reflecting wave will cause square like response (or at least it will be deformed at the reflecting surface).

Might it be important : I use continuous tones only, which -if I understand that manual properly- should only be for the worse because of driver heating up etc., such a test assuming that no longer continuous tone is playing in music, or whatever such a test anticipates upon.
Tell that the organ player.

Peter

[pedal]

Jøkleba LIVE. Its free jazz With awesome SQ. Note some old fashion synth generated looow frequency notes.

Oh yes ! So first there's the more heavy drum with its so nice spread from its peak at 48Hz to the to the left and right (same slope) which creates that ambient sound full with air and next there's indeed what must be a synth with its lowest notes at 18Hz. Notice though that from the latter you'll only perceive its sqaure based higher harmonics but in my view the perceived deep warmth again is this 18Hz.

Maybe I should tell that you can be considered to have a real subwoofer ? I mean, a sufficient amount of drivers in there, but I forgot the size and amount (per side).

Btw a message from Ciska here :
Gry won't be happy with this album. Nor does Ciska. But didn't we know that ...

Best regards to you guys,
Peter

Another wife-buster is this one:
Misha Alperin, Night (ECM)
-A jazz album recorded live at Vossa Jazz Festival, Norway.

Track "Heavy Hour": Here you will hear subsonic bass on a completely new level. The whole stage is resonating through wooden floor and everything. Certainly demo-gallery stuff! (But lock in the children first - this is terrifying music!).

[CoenP]

Hi Peter,

Thanks for sharing your ponderings on the sub frequencies!

Coen, what is this 35Hz based upon ?

Well, it's based upon me being practical on classic horn theory. For -resistive- loading down to the Fc you need at least a 1/4 of the wavelength as horn length. So that will be about 2,5 meters for 35 Hz. Even with a 1/8 space loading the mouth area will still be about the size of an AN-E. Iow these will allready be HUGE. If you don't follow the rules you are either stuck with severe peaking/notching or reduced loading (ie derate the driver and EQ whats missing). Didn't Bert have such a monster basshorn in his showroom?

Now the Orelinos are somewhat of a horn, but they are also something else. On classic theory they won't qualify neither on horn length nor on exitsurface as a horn for an 18Hz tone...
They do have a lot of surface though to move air, about the equivalent of an 18" (or two 15") for the piston. For shure they act as a waveguide given the silece behind them.
It remains a very intriguing desing that seems to work very well.

What I also see from measurements like these (throughout) is fairly excessive 3rd harmonic distortion. Often higher than the 2nd. FWIW : I don't measure any 3rd here. Nothing.

This is really odd  ! Because of the drive symmetry between forward and backward movement I would expect a perfectly executed driver to have way more 3rd H distortion than second. Usually they are in the same ballpark. If I am correct this is also the case for the infinite baffle measurements on the driver's datasheet.
Some cancellation, ok, but NO third???

regards, Coen

[PeterSt]

Hi Coen,

Forgive me, but I certainly don't know everything. In this case I have no clue why a loudspeaker (driver) would excess on the 3rd harmonic per se, while to me any 3rd harmonic only tells about "square" distortion. And "drive symmetry" would incur for distortion in the first place ? All I can see is that when a LS driver would be able behave linearly a nice sine would come out of it without distortion. But a LS driver is not linear (and can not be) so to keep it simple, the tension growing stronger at the outsides of the excursion would create a 2nd harminic distortion when the increase of tension itself goes in a linear fashion. And let's say that to some degree of excursion it will. After that anything can happen and e.g. the moving mass against the increasing tension may not go in linear fashion at all and you get unlinear "holding backs". That's 3rd (more square).

Well, at least I will admit that LS distortions are too complex for me and many exist. But I also have the rather clear idea that maybe not many understand it in the first place, because I see too many strange things written. For example, I just ran into the "fact" that doppler distortion would need two frequencies to be present in order for that distortion to be (audibly ??) present, and personal me does not believe a thing of that. Maybe two frequencies would make it better audible indeed, but the distortion itself is technically there with one frequency already. And if that is not the case then I not only don't understand much, but actually nothing.
Just an example.

It is also clear to me that intermodulation distortion is much more important than just harmonic distortion, which is just the nature of a loudspeaker driver of any kind. Here, we better use a 10-way system instead of one wide ranger and all it takes is perfect crossovers. Do those exist ? maybe. But do speaker drivers exist with 0 IM distortion ? of course not.
What is worse ?
... And again I find nothing. It all is derived to our auditary system and that we will be able to filter out distortions and blabla. Well, I don't believe one f*ck of that as long as the same persons or instances write that 10% HD is also perfectly allowed. In combination it now is about "but IM overwhelmes anyway, so why bother with HD". And in the mean time nobody knows how that IM is perceived, which of course is a tad hard to test while it needs to be about music and not test tones.

Anyway, after diving into this matter somewhat I am shocked to find so much unknowledge, to which I am not used. And then to think that a great deal of my audio life is about finding whatever devices with 0.00001% THD at nano volt noise levels. What to do this for ? Ah, because that is so much amplified.
And still all I try to achieve at that level is audible. Hmm.

I have said it so many times before : there is so, so much wrong with audio that we can improve for the rest of our lives, our grand children included.
But that is nice of course, because now we can keep on working on our hobby.

Peter

[PeterSt]

Another wife-buster is this one:
Misha Alperin, Night (ECM)
-A jazz album recorded live at Vossa Jazz Festival, Norway.

Track "Heavy Hour": Here you will hear subsonic bass on a completely new level. The whole stage is resonating through wooden floor and everything. Certainly demo-gallery stuff! (But lock in the children first - this is terrifying music!).

Hey hey ...

First off I had this album already in my Nice Stuff Gallery.
Next, I thought to play it from the beginning so possibly nobody would notice any nastyness (I regard this album almost experimental classical, might that genre exist).

Then, oh boy, exactly when this track has started 10 seconds I first got the remark from someone here "I reckon this is an advice from pedal I suppose ?". Followed by a "That's what I thought as well !". Ok ok ...

However, this time I have a kind of another remark :
With the notice that the large drum hits reached a sheer 107dBSPL and seeing that the very soft regular large-drum hits easily go beyond 20Hz ... no such "distortion" you imply is anywhere. And do notice that I exactly know what you are referring to, were it about all of the room resonating in a sort of self-mode (waiting for the building to collapse *really*).
Nothing of the sort.

So what's up here ? The 20Hz and beyond for sure is there and at levels of maybe 90dB (I didn't really check, but with the meter at 100 I saw nothing moving for those softer large-drum hits). So careful, because when 20Hz shows its second, thus 40Hz, this really is the rattling of a perceivedbly soon collapsing building.
And of course, when those 107dB hits of the loud drums (between 50-60Hz - I didn't really pay attention) go wrong then all can happen.
And the "length" of your room ? well, that for sure would incur for similar when at the wrong frequency by accident. So, 7 meters on estimate ... 344/7 = 49Hz. And I think I recently told about collapsing behaviour of a track with gliding frequency which works for my room ...

Sorry for the maybe too long post, but always interesting to see how we perceive things and how they possibly are not "real". Possibly ! ...

Peter (open for suggestions)

[PeterSt]

PS: Let me be clear : There is nothing wrong with the "effect" of the longitudinal wave virtually making the room move back and forth (if that's the effect you perceive in the first place of course) and at least for the track that works so in my own room it's a sheer gag. So this is only about "reality" and nothing about things being wrong really. So if this is perceived as e.g. wooden floor vibrating and all you can imagine, why not !

And I can tell you : such an effect is the most precious I have in my "demo" collection. It makes you dizzy and even hallucinate.
Btw, might you (or anyone) want to get it, this is Easily Embarrased - Tales of the Coin Spinner, track 02 - "Blessed Day on Distorted Shape".
I just played it to look at it through FFT and the (stepped) gliding frequency goes from 65Hz to 31Hz and is about 20dB above the normal music (sounds). Beyond that 31Hz is totally nothing. My room is 344/12 = 28,67Hz but speakers are 80cm from back wall, so 344/11.2 = 30,7Hz. Ha.
It now just depends on whether one of these steps exactly meet your room length ...

[PeterSt]

I was cleaning up my screen and found a page still there which I planned to post yesterday. Here it is after all :

http://www.neumann-kh-line.com/neumann-kh/glossary.nsf/root/F77C48111116FFBDC12578B20039968C?Open&term=THD+N

I think nothing is wrong with what is told in there. Whether the real truth is something else.

Hmm ... Since this link is about some "glossary" item for loudspeakers, I just thought to look up Intermodulation Distortion in there. Can't find a direct link, but on this page you will find a link to it :
http://www.neumann-kh-line.com/neumann-kh/home_en.nsf/root/prof-monitoring_knowledge_glossary_measurement
Pretty much the same as I said and implied yesterday.

Peter

[PeterSt]

I have an update on the "Beating" :

I have set up one of my synthesisers in order to find the merits of this "beating" and in the end I succeeded in mimicing the behavior easily;

It requires two fairly low frequencies to be close to eachother (and not too low either because the beat can't be heard then) and I found as example 65Hz and 70Hz to work very well. When these are played together, in mid air (thus not in electronics) these frequencies "beat" and the result is an estimated 4Hz of "tone". BUT :

Nothing from my theories happened, hence my theories were wrong.
What happens is that indeed the two frequencies cancel out and add (at this 4Hz frequency) but this is really all. So, the FFT will not show any 4Hz distinct frequency, and all what happens is that the 65Hz and 70Hz both disappear and get louder. The FFT just shows that.

Still what you perceive from it is a low frequency roar which sounds square like but is not. So, no harmonics appear either. Just those two (btw sine) frequencies hopping up and down and the result is a way more deep perceived tone. I think this is just deceiving but the result is "nice" so to speak anyway.

I must add that I tested this through normal PA speakers and regarding the remaining of this topic I may wonder whether there's merit in that. I mean, might these speakers not be able to produce undistorted low frequencies then maybe they don't show any of that at all. And might that be 4Hz, then of course that won't go anyway.
It is difficult to (without changing setup) to test these speakers for distortion, because the synthesiser I use for it is not able to produce clean sines to begin with. Thus not useful to test the result for THD in that speaker as well.

I will continue examining these kind of things.
Peter

[PeterSt]

For example, I just ran into the "fact" that doppler distortion would need two frequencies to be present in order for that distortion to be (audibly ??) present, and personal me does not believe a thing of that.

Well, that happens when you don't know all and just try to imagine a few things. And yes, of course I derived my imagination from that train (with whistle) coming towards you and from there it will "squeeze" the imaginary vertical waves into closer by ones - thus a higher frequency. What I did not realize though was that the speed of the train is to be regarded one frequency (a veeery low one) and that the whistle is that other frequency. So, if the train comes towards you and while being at you could drive backwards instantly, it would mimic the loudspeaker diaphragm coming towards you and moving back from you at a low frequency, while in that same diaphragm plays a higher frequency as well. What remains is my squeezing (and detracting).

Do we understand now finally ?
I hope I now do.

Anyway what it comes down to (and it always has been) is that the more the diaphragm excurts the more doppler distortion will be there. Or better put : the more excursion, the more difference between the forward moving and squeezing of the higher frequency vs the backward moving and detracting. So, the more excurting the more distortion the higher frequency receives and which is just inherent to the process. Also and to be clear : it is not so that for this doppler effect the higher frequency deforms because of the lower it rides on - it is just an in-air effect; the whistle is perfect and on a rock-steady train, but the moving train towards you will let it sound higher in frequency. And when the train has passed (moves from you again) - lower. Perform this in a faster fashion (like 100Hz) and no whistle sounds nice or pure. Is is not off key (like the train always moving to you) but it is sheer distortion because the frequency of the whistle changes 100 times per second back and forth.

Peter

[CoenP]

I find this doppler distortion rather acedemic. You have to have excursion ánd wide bandwidth to theoretically detect this effect. And how do you measure the effect of the pitch variations, how do they show in the Distortion measurement when they are a tiny modulation of the fundamentals? You may integrating the FFT over a time period of a two tone testsignal and see how wide/high the tone comes out of the speaker...

Besides that the "higher" tone's velocity also influences the pitch "lower" one if you wnt to be complete in the explanation .

Is this 4 real? Did you ever hear it and how does it sound?

Regards,  voen

[PeterSt]

Hey Coen,

I ended my previous post with something like "looks like intermodulation distortion" but I scratched that because it is more complicated. But something like that (it will express similarly).

I've been reading a good article about it and from a clear example we can derive that e.g. 28Hz with 600Hz modulated onto that will give a nice deviation of 1Hz to either side the diaphragm is moving. So, the 600Hz fluctuates between 599 and 601Hz 56 times per second (and it is no real IM because that would be continuously there while here the frequency will flutter to either side of the original (600Hz)
The math is related to the velocity of the "woofer" which by itself deviates from the excursion it expresses and further more from the speed of sound. So, because of the former it also depends on the amplitude of the lower frequency.
Notice that I could fairly easily make a simulation of the distortion figure just from the digital file, if only the woofer's excursion (for a given max reference level) is given. Of course this varies per woofer driver.

Once we know where to look for, this should show as side bands just like with IM distortion. I think it expresses in worse THD just like always, although this by itself can not be measured because of two frequencies needed to perform this testing. Also I wonder whether IM distortion figures will be valid because in my view this is not a steady distortion (but wobbles on the (28Hz from the example) carrier.

But you know what ? concensus is already that with any normal efficiency woofer speaker the distortion of this comes to 7% (just look at the FFT). Only efficient woofer horns can reach 1% and expanding the woofer surface decreases it further. All logic because the excursion gets less.

My conclusion so far (and the real knowledged may laugh) is that it is not a deformating diaphragm or failing suspension which incurs for the major (audible !) distortion, but just the simple doppler effect.
And I said "audible !" because normal harmonics like a 2nd are not so audible at all because related (but never forget the hardly audible 25 Hz which turns into a most clear 50Hz because of this). So, this is just harmonic distortion from "side bands" like IMD would show it ...

Not academic. But I can try to setup a synth sound like this where that second frequency modulates on the first lower. On/Off switchable of course. Not *so* easy to do for me, because of not being that experienced on it.
And maybe never mind this test because briefly thinking about it, any two of these two frequencies (without doing anything further) will already look exactly like modulated on eachother when looking at the digital file. So it really needs good knowledge and judgement set setup a representative test like this. And time.

Peter

[CoenP]

Thanks Peter for the elaboration.

It appears that our ear/auditory system is extremely sensitive to pitch . I found this on the net:

"The normal human ear can detect the difference between 440 Hz and 441 Hz"

So the case for audibility is there.
The two tone analogy may work for explaining the effect when there is a substantial difference in frequency but what happens for multi tones or tones that are close together. What part of the spectrum can be considered "carrier" and what "modulated". When you try to envision music through this effect it becomes a complete mess. Well maybe it is the mess we listen to in our daily lives .

Regards, Coen

[PeterSt]

So many things wrong with audio ...

[PeterSt]

But I almost forget myself :

This is not about us being able to discern between e.g. 440 and 441 Hz, but about a rapid change between the two continuously. To me that theoretically is about sheer distortion (might it be a nice sine that 440Hz).

And so yes, many frequencies will play together, but all it really needs is one frequency to play very low which by that incurs for higher excursion and with that for all the on that modulated frequencies to "distort".
Same in the mid of course, but relatievely much less of importance (because of the fewer excursion to begin with).

Right ?
Peter

[CoenP]

Same in the mid of course, but relatievely much less of importance (because of the fewer excursion to begin with).

Right...but mid has higher velocity...

If I look at my Iphone FFT app, most energy is usually in the 80-800 region (voice and instrument fundamentals). Make shure you have some surface there to reduce the excursion. A subwoofer is wrt this issue a good idea.

Though this doppler thing likely clutters our sound reproduction, many musical instruments could derive character from it (ie singing of snares).

regards, Coen

p.s. Phono cartridge flashback!

[PeterSt]

Coen,

Same in the mid of course, but relatievely much less of importance (because of the fewer excursion to begin with).

Right...but mid has higher velocity...

Is that so ? Maybe not. I think the velocity as such depends on the volume level (energy fed to the driver). Not the frequency. But also the diaphragm surface which distributes that energy. So if we regard the mid bass driver a smaller than the woofer's, then yes. Ok ok, Yes.

This is not even easy at all. Think about it ... a mid bass driver with the size of the bass driver. Actually both are the same and both can extend up to 3000Hz. Woofer goes up to 200Hz and midbass starts there and stops somewhere under 3000.
I wonder whether such a thing has been done and whether it is really dumn to do it. We can't say "yea, but that bass driver is not fast enough". It is, because it is rated for 3000Hz (say).

Peter

[CoenP]

Is that so ? Maybe not. I think the velocity as such depends on the volume level (energy fed to the driver). Not the frequency. But also the diaphragm surface which distributes that energy. So if we regard the mid bass driver a smaller than the woofer's, then yes. Ok ok, Yes.

Think about the distance a speaker travels in 1 second for 50Hz and for 5.000Hz. That's 100X more movement for the 5.000Hz one. You gotta have higher speed to do that !

The caveat is that I assume equal amplitude for this reasoning. That is not the same as equal loudness. The higher tones need less excursion for the same loudness given a certain speaker surface.  In the end equal loudness equates to equal velocity (if I am not mistaken).

regards, Coen

[PeterSt]

Think about the distance a speaker travels in 1 second for 50Hz and for 5.000Hz. That's 100X more movement for the 5.000Hz one. You gotta have higher speed to do that !

You can't be wrong there ...
Leaving out the absolute levels (SPL to be created) it still depends on the surface. So if that 100x movement driver receives a 2x larger surface, excursion will be twice as small which makes the velocity twice as small. Frequency doesn't change.

I'm sure I am winding myself into a knot, but while a higher frequency driver needs to be more fast to be able to cope with the speed needed, making its surface twice as large and it can be 2x slower.

Of course these things will have been beaten to death by those who know all about it, but since it is all not *that* simple, I wonder whether this all has been sorted out to the extend needed. For example : many swear by the full range driver. No crossovers and linear phase huray response.
With 30% of this "frequency modulation" distortion.

You know what I think ? I should make digital filters with infinite steepness (of course they won't ring) and next stack as many drivers as needed to keep distortion ultra low. 1 per octave sounds nice and undoubtedly will make sense somewhere (in aftermath and in somewhere 2020). Needs 11. And a crossover with infinite steepness is no crossover anyway. So, done.
Ok, I need 11 amps per channel.

No, this wasn't serious. But I do think I can make such filters.

[PeterSt]

Here is something else we might put our teeth into :

Let's remember that this topic is about my own personal quest of finding out what actually is happening with the Orelino speaker and its unsurpassed bass. So, I could tear that down to way less harmonic distortion at first because of its design which still would only be harmonic distortion i.e. related to the fundamental. Consider that similar to guys liking genuine NOS D/A converters, which btw are most who try that (over the modern OS types). So, loudspeakers show (very roughly) 7% of that in the lower registers.

By now we talk about Frequency Modulation Distortion which is way more severe to good sound; it is unrelated to the fundamental and its appearance can be regarded random; it's just a matter what plays together for (many) frequencies.
And yes, that 30% I mentioned in my previous post is a serious figure (from more angles).

What this is all about is the efficiency of the speaker. So, the speaker as a whole, but with of course the efficiency of the driver(s) as the base of it.
The global math for the FMD is super easy : 6dB less efficiency implies 2x more excursion. I think this in itself implies 6dB more FM Distortion but I'd have to read into it all once more to prove that true. But I also think this depends on the frequencies, so this is all not *that* easy (once again).

Now if we take as a base my 114dB sensitive horns. Without real values (yet) let's say that this implies a general 0.1% FM distortion. Make that 108dB and it is 0.2%. 102 = 0.4%. 96 = 0.8% and we're already at efficiency levels most have. But it can still be worse of course.

Why do I come up with this ?
Well, because this 114dB can also be turned into 117dB.
And I actually did.
What do I perceive of that ? super speed. So, 3dB more efficient and it is perceived as super speed. Super long cymbals as well. Seemingly (or for real) higher (SPL) output of the higher frequencies - same.
Of course this is not because there's 3dB sheer more output now, so that is weighted in.

This is what I found maybe 5-6 weeks ago. No Doppler blahblah in order which is only now. So, first some empirical finding (FWTW) and now the reasoning. With that reasoning though I am able to "see" how much less smeared this all sounds.
To really see this, we should go the other way around first. So what also happened is that I decreased the 114dB to 112dB. This tiny decrease makes all like with a super thick blanket. Far away background music. 100% smear I say now.

My earlier reasoning was that this is because of more heavy impedance impact. And more resistance to go through. So, electronics. Today I don't believe that anymore. And especially not when you see all the sidelobes this FMD implies. It's just one big mess.
(I know, I should produce pictures of this - but this is not so easy because my horns won't show a thing above the (ambient !!) noise through microphone)

Will be continued for sure ...

[CoenP]

Peter,

It is quite correct what you state: high efficiency reduces cone motion for a give sound level. Especially horns provide a very high resistance towards movement of the cones (like a short circuit). The more efficient the horn, the less movement of the diaphragm.

For the low end where horns become very big towards the impractical, big and paralelled drivers is the way to go.

There are some High Eff related benefits like an underhung voicecoil that improve on the linearity.
Anyway from all angles you should design a speaker for a minimum of cone movement.
Dispite the complexity one optimised driver per decade would be more "practical" than one per octave. Kinda like the Cat's setup .

I wonder though how you legally can get 3 dBs more efficiency out of your drivers (that is 3dBs worth of less diaphragm movement while retaining the same sound level). A longer horn?..

regards, Coen

[PeterSt]

Coen, squeezing out more efficiency is not a secret once you know that the drivers are 118dB from origine. How to do that in well-fashion is though.
If you read this - out of all context - you'd say this can't be related to the excursion. But still it is; matter of knowing this driver. Can't say more but it really isn't important either. Well, for my credibility maybe, but never mind that.

Thank you for your insights !
Peter

[christoffe]

Might be interesting!

How Sound Waves Interact with Each Other

http://www.mediacollege.com/audio/01/wave-interaction.html

[PeterSt]

Hey All,

Although somewhat longer ago by now, I think I can add some new information to the "ambience" topic;

As you may remember, in a topic elsewhere I started to let my DAC (NOS1) float on water. It still did not sink, so all OK there.
The reason I did it was to eliminate perceived "relatively severe" vibrations of my concrete floor. And, audibly this did a lot (if I wasn't placeboed in the first place). However :

The "ambience" topic here was about being able to see sub-low frequencies well beyond 20Hz and which was done by real time FFT measurement. This in itself was related to the Orelino speaker I had set up back at the time and my measurements to get the sub low optimal. Okay ...

It was later that my NOS1 was set to float on water and while me and the family had great fun while enclosing bit by bit what I had done (you trying to guess), it had been the same family which encouraged me over and over to re-measure that low frequency response (because of vibrations, perceivedbly - which now should have vanished). But I was fed up of measuring and I never did it.

Until last week at setting up the new Orelo MKII speaker and now tuning that one for the sub-low frequencies, and ...

Gone.

It is not a real apples to apples comparison (because the speaker is different), but since the Orelo MKII only goes way more low than the Orelino, plus I just could hear it for the all better with the floating NOS1, I just can't make anything else out of it than that it just greatly helps (this floating).

Of course we can see it as a downside that now "vibrations" under 20Hz have gone and so will have the "ambience response" but all I can say is that this was not for real and thus not right.

Of course there's ambience and ambience and the real thing will still be in there. However, thinking about the kettle-drum (in a church) example somewhere mentioned in this topic, I don't think that I will still see responses up to 15Hz or whatever it exactly was; most probably it stops at 26Hz or so now, but I'll have to check it.

So easy to get fooled by so so many things ...
Peter

[manisandher]

Hey Peter, just for my understanding, your NOS1 is still floating on water, right? And you still believe that this really helps, right?

Mani.

[christoffe]

Any „suspension“ of our choice favours the SQ, and Peters approach is very, very special and the result seems to be positive.

Peter can be very lucky that the vibrations/resonances did not damage his housing foundations, especially the walls to the “water front”. (this is a joke, but .... .)
I never experienced such “deep tone” resonances with my feet before. Unbelievable!!

(elephants are communicating ……….; and the French Army made some tests with 1 to 5Hz frequencies with disastrous results some years ago)

Joachim

[PeterSt]

Hey Peter, just for my understanding, your NOS1 is still floating on water, right? And you still believe that this really helps, right?

Mani, yes, still floats. Needs a water top off each 4 days (which to my belief is audible right away).
Whether it helps ... I hope to have described that in my previous post !

Peter