Ultimate Audio Playback => Chatter and forum related stuff => Topic started by: Scroobius on August 11, 2013, 04:15:22 pm

Title: IPL Transmission Line Speaker Revelation
Post by: Scroobius on August 11, 2013, 04:15:22 pm
I have been reticent to post this without someone else whose ears I trust also listening for fear of questions regarding my sanity. Luckily Nick came by yesterday and he will post his thoughts separately. Really this post is about what properly designed, engineered and implemented transmission line speakers can do. However I just wonder if IPL are the only ones out there. I say that because I have heard highly regarded PMC Tx Lines and they were not in the same class.

There is no word other than "revelation" to describe my experiences with IPL speakers. I have now built three speakers in the range S2 (for my brother), S4 (for a friend as he was so impressed with the S2's) and finally for me the mighty S5's.

My comments on sound quality apply to all the above speakers as is seems the speakers are designed for different room sizes and it is not necessarily the case that "bigger is better". Choose your speaker with care!.

Over the years I have heard just about every type of speaker and I have never heard any speaker that produces proper bass. And it is not a question of how low they go it is more about its quality.  Maybe the biggest problem with box speakers is that rear going wave from the driver hitting the back of the box and bouncing back through the drive unit giving rise to colouration and time smearing. Yuk I really do not like that sound and it seems to be present in most speakers right from expensive to cheap. Other speakers have other problems open baffle and panel speakers could work in a big enough room but in the real world who has a big enough room?.

I cannot describe the character of the S5's (or S4/2's) as they do not have a character as such. Colouration is the lowest I have heard. From highs to lows the sounds are properly separated. Each subtle strand can be heard clearly. It is really hard to imagine that the sounds are actually coming from a box. S2,4 and 5 all produce the most natural rendition of human voice with very little boxy colouration. But then if there is some deep bass in the recording it is played clearly accurately without drama just naturally.

Yesterday Nick and I listened to a Grant Green track with some electronic organ. Overall the recording is light and airy with guitar drums and cymbals almost sounding electrostatic in nature. But there is some extraordinary low bass from the organ that I have never heard before that the S5's produces effortlessly - and it is a shock when you first hear it - you almost feel the bass and it just seems to be separate from the speaker. No other speaker that I have heard does this. Guitar and plucked strings just sound amazingly natural.

I have always been struck by how a real church organ sounds in a church. There is a lot of subtle detail, harmonics and little strands of sound. There is no wash of bass in the sound but you just hear little strands of deep bass occasionally and very clean. No speakers I ever heard get anywhere near reproducing church organ - until now. Church organ is stunningly natural via the S5's.

Ivan Lesley (he is IPL) gets big respect from me he has put years of engineering development and tweaking into his speaker range (and particularly crossovers) endlessly playing with crossovers and drivers to come up these transmission line speakers that I have to say I find astonishing. The key has to be removing/reducing that rear going wave problem. What other speakers do that without the real life open panel problems? I can only think of these IPL's and possibly Bert's Waves (but unfortunately I have never heard them). Of course there may be other speakers but they would be outside of my experience.

Just one last thing when any of these speakers play deep bass (and oh boy do they play deep bass) the drive units hardly move - also there is very little air coming out of the port at the bottom of the speaker - a very good sign!.

IPL has turned upside down many pre-conceptions I had about how to get great sound quality from a speaker.

These speakers are not expensive in materials but it could take around a week on and off to make a nice job of building them. But you will be rewarded with something very special.

By the way S5's are big much bigger than they look in the picture.


Title: Re: IPL Transmission Line Speaker Revelation
Post by: SeVeReD on August 11, 2013, 07:55:11 pm
Thank you for this post.  My huge speakers are long in the tooth (or is that me) and I'm beginning to think drivers are not matched anymore, along with some super tweeter concerns.  I like a good stereo image (along with all the more important stuff) and after reading I'm starting to think I'd like to build the S5s... but I go at these decisions very slowly now.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: Nick on August 11, 2013, 11:19:48 pm
I'v been looking forwards to hearing IPLs for the first time. As Paul mentioned he's built 3 sets of different IPLs over the last few weeks and its been fascinating hearing about them from a distance as the results have unfolded.

Well this weekend I heard the TL4s that Paul built for a friend and Paul's own TL5s (in the picture above).

The TL4 delivered a very sweet top end, excellent stereo imaging and  low register resolution and extension that I have not come across before. Not a hint of boom, just real sound detached from the speakers. Paul's friend played an acoustic guitar track, the TL4s made it posible to sense the tension in strings and really hear the resonances of the boy of the instrument. Then there was Massive Attack......... :-)

Back at Paul's in his larger and very difficult shaped listening room the TL5 where really special, absolutely no problem driving the difficult space with a sense of ease. The first thing that strikes you is just how coherent they are, there is almost no sign at all that these are three way speakers. Then you try to analyse the sound only to find your attention slips time and again to just listening to the music. Humm, there is very little that you can latch onto to analyse the speakers are just making music and that's what you end up hearing not "attack" "decay", "highs" "transients" etc etc they do all this but quickly you realise they sound right and just listen.

Highlights are the very tuneful and realistic lows and a very transparent midrange. But they are extremely good top to bottom.

(The above comments on the TL5s are in the context of Paul's excelant PC, NOS1 DAC, and bi amped, bridged gainclones)

In the flesh they are certainly larger then they look in Paul's pictures. Overall very handsome, and a credit to Paul's craftsmanship and IPLs excelant engineering.

A very interesting and enjoyable visit, many thanks Paul.


Title: Re: IPL Transmission Line Speaker Revelation
Post by: listening on August 12, 2013, 06:30:13 am
Hi Paul,

the TM loudspeaker principle surely benefits from the xxhighend software. A lot of years ago I owned a pair of IMF TLS 50 and was very satisfied - until I moved to another location. I got a lot of resonances in the new room and sold the speakers. It would be interesting to hear them again  ;)


Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on August 12, 2013, 09:45:25 am
I forgot to mention that about 18 years ago I built a pair of Transmission Line speakers based on what was a very highly regarded design at the time. We were still in the same house then but the room was a different shape. My experiences with those TxL's was very different they just did not work well whatever I tried. I had had big hopes for transmission line speakers then and I was disappointed.

However back in those days I do not think there was a mathematical model for TxL's. There is now though and with much engineering and development (by someone who has passion and dedication) the results that I hear cannot be compared with that early effort.



Title: Re: IPL Transmission Line Speaker Revelation
Post by: manisandher on August 12, 2013, 07:41:43 pm
Hey Paul/Nick, thanks for sharing your thoughts.

I'm planning on taking a trip down to Paul's next week (exact day still TBD) as I'm really interested in hearing the IPLs for myself. I've visited Paul's place on a couple of occasions already, the last I suppose around a year or so ago, and have been massively impressed - totally different sounds on both occasions, but both absolutely listenable. So my expectations are nigh-on stratospheric this time. I'll share my impressions as honestly as I can once I've visited.

More next week...


Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on August 12, 2013, 09:58:54 pm
Oh Dear!!!! - Stratospheric expectations is a bad thing - they can only lead to disappointment.

I made the first of a couple of tweaks to the S5's today so that they work better in this room. The result is that with one quick tweak to internal damping (after a long chat with Ivan) I was able to achieve pretty much exactly what I aimed to. But of course extended listening is needed. There is another tweak on the way ..... watch this space!!! I shall be looking out for a little parcel in the post over the next couple of days.

So these speakers start off sounding really great but then in addition there is the freedom to modify them to match the listening environment. Manufacturers of speakers do not stand a chance!!


Title: Re: IPL Transmission Line Speaker Revelation
Post by: Mamba315 on September 21, 2013, 08:47:42 pm
Any update on the S5's?  I am in need of some affordable speakers to tide me over while Peter and Bert finalize their design.  I was considering the waveguide S5's.  I have a friend with a wood shop too, but not sure if he would let me use it yet.  I think I would prefer wood cabinets over MDF though.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: PeterSt on September 21, 2013, 09:03:02 pm
Haha, I don't want to interfere, but the design is ready by now. Playing here as I never heard anything before.

That's all !

PS: Sorry, but I had to respond to that.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on September 21, 2013, 10:03:56 pm
Hey Peter - The point is the performance versus COST these transmission lines are absolutely superb. Better than anything I have heard to date overall (REALLY). And they are silly silly cheap (but lots of hard work to build).

Apologies Mamba I do not know your name but you are very welcome to come along for a listen (and a coffee and a chat) and make up your own mind.

For anyone prepared to put in the work these are the bargain of the century. Really.

BUT BUT BUT you must make sure the speakers are the right size for the room. The S5's can put out a lot of bass energy the S4's are also superb and will sound better in a smaller room.

Peter - the Orelino's look fantastic and the design and engineering fantastic but for sure they are going to be VERY EXPENSIVE and not everyone has pockets that deep.

UNLESS that is you can say otherwise. I hope you (or Bert) can because you will have my order tomorrow (REALLY). But I know you cannot - 6 x 12" bass drivers just for starters mmmm then the horns the woodwork the in built electronics etc etc - please tell me I am wrong but that is serious dosh.

The IPL's are designed to be neutral and they are very revealing so you must make sure your front end is excellent.

How do they sound? - neutral & natural not dramatic in any way. They will just make what you were listening to before sound coloured (IMHO that is).



Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on September 21, 2013, 10:53:33 pm
Hey Mamba - I forgot to add that the waveguide S5's are what I originally looked at but after a chat with Ivan (the designer) he recommends the ribbon tweeter version for better sound quality. The waveguide version was made for very low power amps.

Also I did not properly read your post I missed that you are waiting for the Orelino's. That is great. For sure you cannot go wrong with the S5's whilst you are waiting.

If you are going to build them from wood maybe have a chat with Ivan first - he has taken great care in the design to get neutral sound and that may be affected with wood. I am sure he will have experience of that or someone who has built them will have.

Anyway hope all goes well if you do go for them.



Title: Re: IPL Transmission Line Speaker Revelation
Post by: Mamba315 on September 22, 2013, 09:59:20 pm
  The Orelino's are ready perhaps, but the other?

  Quite right about the massive cost difference between these IPL's and those Orelino's.  I think I need to save more money if I go Peter/Bert's method.  Just in case something unexpected were to happen.  In the meantime, I do need something better and these IPL's are under strong consideration.  I live in the States (California) so an audition may be somewhat difficult for the IPL's.

Am surprised to learn that the waveguide version is for lower powered amps.  Sensitivity is only 1db higher (92 vs 91) and power handling is actually much higher (500 watts vs 200 watts).  Did he really say the regular S5's sound better?

S5's could definitely do well for my present location.  How is the SQ as you walk around the room?  In practice, I'm rarely in the sweet spot.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: PeterSt on September 23, 2013, 08:13:32 am

The others are the same and two pairs are being build right now. But maybe this is too much secrecy and I better send you a mail.


Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on September 23, 2013, 08:54:15 am
Hi - Yes I was surprised as sensitivity is so close to the ribbon version - but Ivan was clear that the ribbon version is best for SQ.

My S5's are 8' apart and I sit a non ideal (for imaging) 27' away from them so imaging is not a priority for me. There are four seats available around my seating position and the sound is fine in all those seats.

As you will see from the photo's the ribbon tweeter is at the bottom of the three drivers so the speakers need to be angled back.

What size room do you have? The S4's may be worth considering also they work in a wider range of room sizes.



Title: Re: IPL Transmission Line Speaker Revelation
Post by: PeterSt on September 23, 2013, 09:20:11 am
What size room do you have? The S4's may be worth considering also they work in a wider range of room sizes.

I really (really) don't want to interfere, but since Mamba's room is maybe the nicest I have ever seen, which right away makes it the strangest ...
... I will try to answer for fun. Ok, to help.

Now let me estimate ...
43'-46' from all sides to all sides. I am implying a circulair room here.
Height maybe 33'.

View from the room is outrageous. But that's something else. :)


Title: Re: IPL Transmission Line Speaker Revelation
Post by: Mamba315 on September 23, 2013, 09:48:10 am
Okay yes, circular room.  In reality, 24 foot diameter with perhaps 15' ceiling peak in the center.  Feels bigger though..

Speakers are placed to either side of 12 o'clock.  Doors at 3 and 9 o'clock.  Always sounds better with both doors open, FWIW.  Room is mostly "invisible" at bass frequencies.  A wee "peek" of the ocean and the best night sky I've ever seen.

This room could take the S5's but if I have to move?  Thats the question.  I want something usable in a variety of room sizes for that reason.

How long did your various IPL builds take?  The construction is a big question at this stage.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on September 23, 2013, 10:56:20 am
Hi Mamba  -  Ha ha so your room is about half the size that Peter remembers WHAT ON EARTH was he on? he must have had a great time :). Views of the sky and the sea sounds perfect to me!!

The S5 is a big beast and it has low WAF if that is an issue for you. The dimensions are all about sound quality and not looking pretty. They are about the size of the old Linn Isobarik's and very heavy - sensibly it takes two to lift one S5. So you can get the idea that they are hard work to build if for no other reason than their bulk when lifting and shifting. Realistically I would say about 6 days work at something like 5-6 hours per day. But a big chunk of the work is the veneer especially if you want to make a nice job of it. But maybe if temporary you could leave that until later or paint. When lifting the S5 to get positioning right I can only just lift one speaker - and I am 6'3".

The S4's will take 4-5 days and are significantly easier to build. The crossover is much easier to build for example and it is an easier speaker to lift and shift around. Also you could leave the veneer until later if that suits.

My room is 42' long and the width varies from 33' to 15' and is a "pig" sonically (no views of the sea though  :( ) but the S4's worked well even in this room.

The S4's are going to work in a much wider range of sonic environments. Why not give Ivan a call? he gets a lot of feedback from many customers using a very wide range of acoustic environments and he really knows his "stuff". If you do please tell him you have been talking me (he knows me as Paul from Marlow!!).

Ivan recently received an order for a significant number of S4's to reproduce live church organ music!!!. They are excellent speakers and incredibly neutral and natural sounding. And that Fountek ribbon is just gorgeous.

Best of luck!!


Title: Re: IPL Transmission Line Speaker Revelation
Post by: GerardA on September 23, 2013, 09:34:09 pm
Hi Paul,

Can you give me the brand and type of the speakerunits and the crossoverschema? I'd like to do this really DIY.
But for the record, I have big TL's here that sound perfect, but the Orelino's are really something from another world! :unsure:

Title: Re: IPL Transmission Line Speaker Revelation
Post by: Scroobius on September 24, 2013, 11:06:53 am
Hi Gerard,

You do not have to buy the complete kit all the parts are listed on the website and can be bought separately. You can make the cabinet yourself. But make sure the drivers and crossover parts are all matched that is really important.



Title: Re: IPL Transmission Line Speakers - we seek advice from Scroobius
Post by: JustinG on July 08, 2018, 05:43:20 am
Scroobius, congratulations on your Orelinoi speakers, they must be lovely when you have the room and positioning tweaked to perfection.
I am not jealous of you, as these would not suit our purpose, though I am envious from point of view of how good they must sound.

Sorry to be bothering you with this giant email, but we have no chance of hearing these before we buy, and for both of us, the decision is a long-term choice for us.
These will probably be the last speakers we will ever buy, it is a luxury purchase for us sanctioned by our wives.
There are two, possibly 3 of us who want to build these kits, S4TL or S5TL. We are all 50-60 years old, and our musical tastes come from the late 60s to 80s with some other stuff later than that. This includes Floyd, Mark Knoppfler, Massive Attack, Classical, some jazz, lots of rock and blues, and a mix of everything else including (shudder from me) Michael Jackson and Tina Turner stuff that the ladies like to dance to. Ugh. Also lots of other stuff.

I currently have TDL speakers, the little RTL2s, which I bought in 1997 bass only down to 40-45.
Harry has Tannoy 15-inch dual monitor golds in small-ish Tannoy enclosures – bass only down to 40-45.
Garth has 2 different sets of B&W speakers, neither particularly high-spec.
We ALL have wives with a love of music, one of whom likes to play it loud and dance. We love rock and blues, some classical – I have a fondness for classical and in particular, I like organ music.
We all miss the deeper frequencies that live between 20-45Hz, and we all want them.
We all want to feel the music, playing loud or playing soft.
We ALL like to feel the visceral impact of deep bass, but who doesn’t if it belongs?
We all like natural sound for voices and instruments.

None of us have the budget to buy commercial speakers of the quality of the IPL range, and we are excited about the project and the prospect of truly great speakers.
We are trying to choose between S4 and S5.

I have modelled the S5 size box in our sitting room, and it looks fine. The room is over 27 feet long and around 14 feet wide at the narrowest part, being very high ceilinged with a sloping roof between 11 to 18 feet high. Speakers will be placed approx 4’ from the side walls, and about  7’ apart. I sit about 17’ from the back wall on the long axis, with the speakers firing the length of the 27’ room. My TDLs work well here placed about 14” away from the back wall.

The main part of Harry’s listening room is 40 feet by 16, also sloping ceiling with height around 10 to 16 feet, his listening position is normally around 16’ from the back wall.

We like hifi sound, but we love music, and sharing it with our friends. We sometimes take the speakers outside and let them breathe. We all take turns to play one of our favourite bits of music. The speakers all sound WAY better out there than they do in a room – bass is cleaner and open, no nasty room effects, and the bass does NOT sound reduced in either of our sets of speakers when we use them like this. This is very surprising, but true.

We are NOT over-driving the speakers here, they are just “normal” loud. We may be pushing as much as 15-20 watts RMS into them, but not more than this. Seating position in this mode is between 12 to 18 feet from the speakers spaced so that they sound best. I have never harmed my TDL RTL2s (6 inch bass/mid drivers) with these amplifiers, and they are loud enough at those levels without taking the amps anywhere near to clipping.

Harry is certain that if he builds one of the kits (he will make that decision after hearing my build) he will build the S5, not the S4, and I would be sad beyond all belief if his S5s sounded noticeably better than the S4s if that is what I build.

We really need the OMG response for these speakers from our wives, as otherwise they will scorn us for the rest of our born days. They will expect and demand to buy any number of expensive shoes and handbags from now onwards, at great detriment to our sanity and overdraft.

For our own sakes, we want to build the best sounding loudspeakers that we could never afford. I honestly believe that both S4 and S5 are able to deliver clean sound in very low bass frequencies, but my sense of the many reviews and projects I have read indicates that the S5 is possibly a step above the  S4 in really low bass reproduction. Also, at louder volume, my guess is that the S5s will hold the midrange together better, whereas I almost expect that S4 at louder levels may suffer slightly in the important 1K – 3K range – but maybe I am wrong on this.

You have heard both speaker, and know the differences between them. Let me ask some questions for you to answer with your own valuable opinions, and we will at least have more information on which to base our decisions.

So, questions.
Naturalness of voice. Is this equal between the two.
Souza marching band bass drum, Biggest Orchestral Tympani, Big kick drum from rock type music.  Is this sound the same impact wise and accuracy for S4 and S5?
Deep organ notes  - does the S4 have the body and power of the S5 at normal listening levels?
Is there ANY noticeable dip in the S4 frequency response between 25 Hz and 50Hz.
Is there ANY noticeable dip in the S5 frequency response between 25 Hz and 50Hz.

Is the mid-range of the S4 as un-fussed at louder levels as it is at normal inside listening levels.
Is the mid-range of the S5 OK? It seems on spec as if the mid-range driver is too inefficient to match the bass driver and tweeter, but I believe that in the real world it all works together perfectly.
What about the S5 tweeter placement – it just looks wrong. I think it should be at the same height as the mid-range if that is possible, not so low down in the box. This business of having to tilt the box backwards just seems like a workaround for a tweeter placement that is a bit unusual in a floor-stander.
Finally the most important question. Do YOU have any major preference for one of these for your normal listening? They will be different from each other, but is the difference quantifiably better in S5 compared to S4? You must like one more than the other for your own music, and I wonder if you prefer S4 to S5, or maybe even one of the smaller sets, like S2?

Honestly I am leaning towards the S5s, but may do the S4s. Harry will almost certainly build the S5TLs if the sound of whatever I choose is as good as I expect.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: PeterSt on July 08, 2018, 10:11:35 am
Hi Justin,

Thank you very much for this nice read on a Sunday morning.

I noticed you mention "we" a dozen times, and I like to tell you that you seem to assume a context - but it is not there. Not in the forum post. So in case you forgot, this context was given by you in your email of March 9, possibly March 10 on your side of the world. I just read it again, and I think it is very suitable to put to the forum just the same. Especially the "we" is special and not what people might think when they read it without context.

Would you care to just copy 1:1 that text from this one email ? Thus, from this long email to both Paul and me, starting with "Congratulations on your [...]".

I think it is very special that you took the time to write this all down afterwards, which often is the thing to forget, also taken into account the time passed after the first eufori.

Kind regards from here,

Title: Re: IPL Transmission Line Speaker Revelation - how they sound
Post by: JustinG on July 09, 2018, 12:21:43 am
Hi Peter, thanks for your reply. I have done as you suggested and posted the original email in the place where this was before to give the context.

Yes it is now July 2018, and I finally completed initial build and assembly of the IPL S4TLs I ordered in May. Scroobius (thanks mate) advised us to choose the S4TL, as did Ivan from IPL, and we decided it was good advice to follow from the only people we knew with first hand experience of both S5TL and S4TL speakers.

The S4TLs use the Hivi 8" driver and the Fountek CD 3 Ribbion tweeter. I wanted these to replace my old 1997 TDL RTL2 speakers which are a similar sort of Reflex / Transmission line design. I was looking for more punch in the gut and better accuracy in low bass, and I hoped for greater clarity in mid-range and treble. Ivan has been refining this S4TL design for many years, maybe 20-25 years now, and perhaps now the cross-over and units selected are as near to perfectly matched as is possible. I followed his design exactly.
I have played them now for about 5 weeks and tested them against different speakers in different rooms. For comparison, we are talking about my TDL RTL2s, and a pair of approximately 2000 vintage Tannoy dual monitor gold HPD 15" speakers in 150 Litre Tannoy enclosures.
The IPL speakers are amazing. Scroobius mentioned "Revelation", and that's what these speakers do, they reveal so clearly things that were only hinted at by other speakers, and even earbuds.
They have such tight control over the bass, there is not a hint of boom, but the low bass is there. All the way down low, it plays musically, with no hint of the "sameness" boom you get from speakers with less range at the low end. Anything which previously sounded like it was at the low limits of my TDLs or the big Tannoys is now delivered tunefully, calmly and distinctly by the IPLs.

Massive Attack's "Protection" album is full of soft and soggy and very deep bass.  The IPLs maintain complete control over what really is very bass-heavy stuff, while providing such accuracy in mid range and treble that we were immediately hearing things we had not really noticed before. Again, the bass notes are clearly presented as separate, musical and melodic notes, always.

Police's "Walking on the Moon" (re-mastered) has such incredible attack on the pedal drum, it sounds like it is being hit with a wooden stick, not a soft pedal - there is a real crack to the impact that really belongs - you can hear it that way on headphones and earbuds. Sting's high tenor is all there, but with no hint of strain.
They are just as revealing of treble and mid-range. I heard fine and fast  cymbal work in "Sultans of swing" that I had never noticed, even on my earbuds. This occurs at the very end of the track just a few seconds from the end where the final short guitar solo is at its peak, yet there in all that loud sound is the super-quick, (maybe treble-time) tapping of that fine cymbal sound. Of course, now that I have heard this on the IPLs, I can tell that the sound is present in the earbuds and those other speakers, but I only hear it now because I know it is there, and where to listen for it. The clarity yet smoothness of the tweeter is amazing - I cannot imagine improving on that tweeter sound with these speakers - that balance seems to be exactly right - accuracy and attack without ear-piercing aggression or undue sibilance.

The mid-range is controlled and delivered very well by the Hivi 8" unit and the crossover appears to be invisible. We were able to listen to "difficult" music that screeched at you on other speakers - with the IPLs it sounds pleasant and controlled even at very high volume. We had a fun time dragging out "difficult" songs that we loved, and playing them really, really loud, without needing to turn the volume down when the previously screechy section of the song arrived. Prior to the IPL test, we always reduced volume for these passages.

Words to describe these speakers... revelatory, controlled and authoritative, but most of all, just plain musical. There is no colouration that I can hear, this is particularly obvious when listening to news reports and other human voice soundtrack from TV or movies - the speakers do not have any boxiness or bassy colour to them.

We have played these very, very loud, and also very soft in two different rooms. Both are big enough to hold these speakers, but they have quite different brightness. I have found that their positioning is both important and variable, it is worth moving them around a bit as even an inch or two  can make a big difference TO ALL ASPECTS OF THE SOUND.
In my room, the speakers work well in two places - 12" away from the back wall, (not 10" or 15") and funnily enough, they work fine just 4" away from the back wall. Weird, but then again our room is a weird shape with a very high ceiling. Currently they are sitting 4" away (which is the nicest for WAF) and sound just about as good as they do at the 12" position. In my friend's room, they were also fine at about 12" from the back wall.

Am I happy? Well yes, these speakers have delivered everything that I was hoping for. Clarity and musicality, also the "feel" of very much bigger units than they actually are. There is a certain "Grandeur" to the sound of the 15" Tannoy Dual monitor golds, which while not necessarily accurate, is very attractive, and these IPL speakers go incredibly close to replicating that same sense of grandeur in almost every track we tried, but with a sound stage and an accuracy that is obviously far greater than that delivered by the delightful Tannoys.

I took advice from Scroobius who has built 3 IPL kits, and I stuck rigidly to Ivan's design. The build was not as easy as it is for those with full kits from IPL. Because I live in NZ, I could not afford to ship the 50Kgs of MDF here. I had help with cutting MDF, but this was not a CNC machine - just a big table saw, and I had to cut the various holes etc myself. Nonetheless, the build was easy enough, the hardest thing for me being the soldering of the cross-over, and the fitting of the bracing and the foam. These were not really difficult to do, but it was fussy work for somebody with such limited DIY and electronics/soldering knowledge as myself.
I have seen comments from some people suggesting that these speakers have some lack of this or the other in the sound, or that they are "woolly" but I really think that must be room issues, incorrect stuffing, or placement issues (it makes a GIGANTIC difference with these speakers). Maybe earlier versions were not as well matched with cross-over and stuffing as they are now. I say this because the accuracy and separation of the instruments with these speakers is incredibly accurate, more so than our other speakers. The sound stage with earbuds is obviously more distinct, but the sound is not otherwise noticeably different, and these IPLs truly deliver something close to earbud accuracy and "crack" on drums,  and all other instruments, but with real gut-punch IF IT BELONGS. The IPLs do seem more revealing than the earbuds, but I do not really understand how that could be possible. I can hear the sounds on the earbuds, but had not noticed them before hearing it on the IPLs.

I have found that at times the IPLs sound LESS bassy than the other speakers we compared them to, but that seems to be at points to do with resonance and the limitations of the one-note sound at the lower end of those speakers with less range. The IPLs always sound more controlled and tighter. There is no point where the IPL speakers boom at you. So to our ears, they are the exact opposite of "woolly". Also, I may be just imagining this, but it seems to me that they did seem to get a little better once they had done a bit of work, though they were obviously and extravagantly amazing the very first time we connected them.

Again, am I happy? Yes, but these things show EVERYTHING, so trying to listen to Layla (Derek and the Dominoes) is now really hard, because you can tell just how awful the recording is, and that is the same for a lot of the music I love. Be warned, these are so accurate that they will show all the badnesses in your system, from source to speaker. I did not fully comprehend this warning when I read it myself, but it is oh so true. If you want hifi, then these are for you. If you want to listen to poor quality recordings with the same pleasure you did before, then forget it and stick with what you have.

Sorry, I just re-read this and thought how arrogant it sounds - forgive me. I mean to say that these speakers are way better than I could otherwise get for the same money, with high quality units in a sophisticated and well-proven design. Of course most of you on this forum will have better sounding speakers than these anyway, but probably not at the same amazingly cheap price. I wanted to share my experience with these in case any others of you are considering an upgrade of old equipment, and wondered what these IPLs sounded like to us, and our wives. The wives are very impressed, so we are happy with our choice. Thanks again to Scroobius for his help with this.

Title: Re: IPL Transmission Line Speaker Revelation
Post by: PeterSt on July 09, 2018, 11:03:55 am
Very nice, Justin. Thank you very much.

Kind regards,