Leo hi,

Im so pleased that you have had such enjoyable results. They really are quite something. Even after a long period of time the sound still raises a  smile.

Kind regards.

Nick.

Peter,

I just reread you post again. You absolutely nailed describing what is happening here 

Are you doing this in software   ! ! ?

N

Peter hi.

Your post on transient response above is really interesting, I get the sense that we are hearing very similar probably the same effects.

In my post on consistently tuning the PC  (moved to this thread above) in order to kept  things simple i gave only basic descriptions of the "sharp", "smooth", and "sweet spot" sound characteristics. This was to place emphasis in the post on the consistency of results obtained from all of the tuned points in the pc.

Your post brilliantly describes some of the qualities of the "sweet spot " sound and the "sharp" sound I hear here. Particularly you descriptions of transients seeming to be less "square" in nature but actually much more true to life. The fresh / sharp sound appears to have speed and attack but its a "hifi" sound, not a real and true to life. At the sweet spot you can hear, almost see, the "nature" material the instrument from and way for instance cymbals are being played. Also your  descriptions of bass reproduction is ringing bells (haha). The heavenly trimmer post over in the "hunting for noise" thread was also trying (less articulately  ) to describe similar sound changes.

For me it took my resent chance to listen to live church organ music in a cathedral for me to really be confident that the presentation of the PC and usb trimmed sound, with its different portrayals of transients etc, is truer to life.

This is great that similar changes are giving what appear to be consistent  results and I was smiling reading your post because you  nailed the analysis and description of the sound so well (and much better than I could put it across).  There is a question of the size of the overall change to sound though now. Are you planning to put high quality tunable clocks in at both end of the usb link soon ? I think the major improvements on offer from the usb link might come from this.

Regards.

Nick.

Hi Peter,

Im in a push to sign agreements before Christmas at work so iv not had chance to read through this weeks posts in detail.

It would be great to compare i2s data to wav and I can proberbly capture something. The issue may be that my data analyser can only reliably capture to 4x upsampling rates. For the usb connection this may be fine as that will still run at 480mhz and errors may still occur. To understand transfer problems in the pc it would proberbly need ability to capture at 16 times. This is mased on your post above where you mention that data could be dropped at points in the os due to resources of the pc not being ready.

Ill think about how to set the test up for x4 upsampling rates.

Regards.
Nick     

Thanks Peter.

Cheers,

Nick.

The aim of this thread is to report activity that concentrates on finding / addressing  digital and analogue noise in the pc and dac playback system. The following post was made here on the basis that the effects it describes may relate to unwanted signal components (noise) introduced or omitted by the transfer of data between pc subsystems and my usb dac.

For continuity in my reporting in this thread I have linked to the post which was moved to a new location without reference to it being made here.

http://www.phasure.com/index.php?topic=2784.msg29291#msg29291

Juan hi,

Its times likes these that make you wonder where the need is  for expensive kit with XX and a NOS1 as a front end. Great story 

Best regards

Nick.

I just dropped back into the thread whilst commuting on the train. I turn my back for a few hours and it's going to take a week to catch up  , really fascinating stuff !

Just one thought is anyone able to test the turning measures I mentioned in the post last night. Do other people get similar hardening smoothing and sweet spot sound from ram speed, bclk and cpu ratio settings. I know not many at the moment can play with usb clock speed but it would be good to know that the observations are repeatable.

Nick.

Peter,

I think with the merging with this thread the "consistent tuning of the pc" post I made is now out of context  even 




This thread which deals with about 20% of the scope of the post I'made at best.

My intention with this post is not to further the discussions on usb turning, potentially there is much broader and more profound points to be debated stretching across the PC and dac system.

If the post must be moved (although I fail to see why as it was the ,"hunting for noise" thread that started the in depth reporting on usb clock experimentation after all), it should be placed in a new thread please.

Nick.

Anthony,

Nice idea I had not thought of looking at a cf-sata adaptor, iv been looking at hdds so far. Ill take a look at cf-sata adaptors as well 

Nick.

Peter,

No problems, I'm trying hard to make sense of this myself. Perhaps you could point me at the points in the other post which will help me understanding your thoughts.

Having thought about this overnight regardless of theory there is something happening at the boundaries that changes perceived sound characteristics  and the effect sounds at least similar to jitter but again thinking overnight about this I think the I should not jump to any conclusions here.

As mentioned above could this be data loss ? Seems unlikely.  Or perhaps a transmission pause at an asynchronous boundary causes the cpu to go and do something else and this effects other processes I dont know, or something else....

What there is to work from is that there are consistent timing related sound changes where asynchronous transfers are taking place as Anthony pointed out. Beyond that I can't really go far with experiment other than to practically  test to see if the principle holds for other transfers like from the hdd.  I wonder if testing software to test the effect might be possible / interesting, i dont know.

I was reflecting last night that i had come across  the cpu ratio and ram speed effects before but its the usb clock work and putting this together with the pcie 100mhz transfer speed that allows the effect to be heard consistently and hints at a general principle at play at asynchronous boundaries.   

If you can point me in the direction of your thoughts I would like to take a look.

Regards,

Nick.

Peter,

What are the options if not jitter induced changes in sound ?

So far back into the pc im not thinking this could be about analogue domain noise. Also a consistent effect from a similar situation in 4 different locations in the data chain and the sound characteristics sound like jitter spectrum.

The only other thing that springs to mind is that could have an effect like this would be data loss. But could this ? Seems unlikley.

So why the hairs rising at the mention of jitter ?

Nick

Edit actually when I say jitter im lumping in the idea of "lateness" of data moving through the sub systems. This could be different to jitter in a continuous stream I guss, a time related effect though. Actually maybe this is more likely.

Then there could be something that happens at an interface that effects other cpu processing. I guess this could be other stuff rather than jitter.

Anyway by all means move the post but im really not seeing how this fits with "usb clock experiences" if that is the post you had in mind. That post considers the effect of a single link in the chain whereas the discussion here should try to address a fat broader scope. In time I hope that with more experiment here the transfer from hdds can also be included or excluded in the scope of this discussion.


 

Peter hi,

For me trimming is not really the point of the post.

The underlying points are:

 Highlighting that jitter may be produced as data is sent across pc subsystem interfaces.

That the effect of conditions at these interfaces have consistent effects on sound and,

That the understanding of these sources of noise might help develop ideas on the underlying reasons behind the jitter. Could this be wait state related ?




The effect of tuning on sound quality is not so much of interest as it is what the observations might highlight about digital noise. Im sort of excited as the pc hardware has always appeared like a black box and here may be something that links cause and effect with  consistency, something that shows logic at  last.

The effects need to be further tested but the interesting conversation for me is what is happening to impact noise.

Cheers,
Nick

Paul hi,

I'v been playing with "long latency" settings again because these a sort of known quantities (in give exceptionally good sound here) whilst trying other tuning stuff out.

I'll have another try with q5=1 again and post back.

Cheers,

Nick.

Hi,

This is a post that i’m really pleased to be making, there is a very nice gain in sound quality but I'v had a feeling that there should be a more consistent approach available to tuning the PC and NOS than I could find before.

What is here is the coming together of work on clocks, messings with BIOS settings and some help from the NEC USB chip datasheet the George posted a few days ago.

Lets start off with some sound quality characteristics that come about when tuning USB link clocks using the dexa "heavenly trimmer" haha (first touched on here  http://www.phasure.com/index.php?topic=2784.msg29143#msg29143)




So as the dexa usb clock speed at the PCIe USB card is tuned there are three sound quality conditions that occur:

1)   Sound characteristic 1 is super smooth, it sounds right and very appealing but when listened to you realise that dynamics / transients / weight / scale / and presence have suffered BUT the hardness in 2) has gone which is good.

2)   Sound characteristic 2 has a harsh element in the upper frequencies too much sibilance and on very complex passages particularly with lot of high frequency energy it feels loud in a poor sense.

3)   The “sweet spot”, sound characteristic 3 has smoothness and detail with good portrayal of dynamics / transients / weight / scale / and presence in addition there is detail but without the sibilance and harshness of case 2.
As you tune the dexa clock trimmer the tipping point to move from sound 1) to 2) via 3) (the sweet spot) is very rapid and takes a little work to find where sound 3 is to be found.




So far so good, some folks might recognise the sound types described. I have posted before on the CPU BIOS clock ratio setting and memory speed needing to be carefully set, on thinking these experiences and the dexa trimming about I was starting to see similarities in the sound types produced.

Then whist reading the NEC Data sheet that kindly George provided it was clear that data is being clocked in to the NEC chip from the PCIe bus which nominally runs at 100Mhz, hummmmm.....

So thoughts moved on, what if the main music data transition points can be tuned going backwards up the data stream from the NOS1 all the way back to the HDD, AND what if they behave in a similar way ? Now THAT would be something to work with ! -  a common principle that might be applicable to much of the PC and the USB link into the NOS.





So possible tuning points working back from the NOS upstream to the PC:

a)   PCIe USB clocl speed => NOS USB usb clock speed (using dexa clock trimmer on the PCIe USB card)

b)   PCIe bus speed => PCIe USB card clock speed (set using BIOS BCLK setting)

c)   CPU speed => PCIe bus speed (set using BIOS CPU ratio, (need an Extream mode lntel CPU for this) )

d)   RAM => CPU Speed (using BIOS Ram Speed setting)

So when tried the interesting thing is that each of the above four tuning points have exactly the same effect on sound. When the upstream side of the data transition is fast I get sound chrateristic no 1 when it is slow I get sound characteristic no 2 and then there is a knife edge transition setting which produces the sweet spot 3 in each case !

As an example a change in BIOS BCLK setting of less than 1% hops over the sweet spot setting from sound no 1 to sound no 2. In reality BCLK of 100mhz in BIOS = sound characteristic no 2 and Bios setting of 99.5mhz = sound characteristic no 3, the sweet spot, BCLK of 99mhz gives sound no2.

So I have spent  the afternoon messing about (being suppressed at the similarity of the effect of tuning each parameter) working from tuning points a) to d) above. At the end of this process sound is really excellent, better than I have heard before, silky smooth with ultra detail, coherent and with presence and scale tone and authority.

By a happy coincidence, last night I went to a carol concert at our town's cathedral to hear my daughter sing in a choir. It was a really nice evening but it also meant that I was listening to live church organ last night. Today with the tuning above the sound of reproduced church organ is very very close indeed to what I was hearing last night.





Settings on an ASRock z79 Extreme 4m mobo ended up as follows.

CPU BCLK = 99.5mhz
CPU ratio = 29
RAM 2100 Mhz
Dexa clock at the PCIe USB card 1/16th turn (about) clockwise from standard position (note running against a dexa set to standard trim position at the NOS USB interface.

Final thoughts.

I am strongly suspecting that the above may have something to do with any “wait state” that data encounters as it goes from one PC sub system to the next introducing jitter somehow. I'm also very excited about this, its the first time for me that a consistent approach applied to multiple points where speed can be tuned has resulted in totally consistent effects on sound quality.

Now I’m considering accelerating a project I have started to put a tuneable clock on a HDD, I know what I think it may do when tuned - but will it !! 

Best,

Nick.