USB cable and Sound Quality - Page 35

Quote:

Originally Posted by grokit 

 

 

That's what I was thinking, that Stommager was describing how an asynchronous DAC works. In an adaptive DAC, we are relying on the computer's internal clock for better or worse. The bits may get there on time, but not necessarily in time. IMO there's a difference, and that's where jitter issues can come into play.

You are talking about packet jitter rather than timing jitter I assumed. With packet jitter, the difference can be solved by the buffer unless the latency is extremely large, then you might have buffer overrun or underrun. In either case, this will result in skipped sound or pop corn noise.

Quote:

Originally Posted by liamstrain 

On playback? It cannot. If anything, it helps since it has time to compensate for data transmission errors. 

Exactly.

I still fail to understand what all the previous 5 pages have to do with playback. Digital audio has clear, easy to hear issues if there are any, or none at all.

Its been designed in a way that if it breaks, it'll produce obvious issues. Otherwise you won't notice anything.

Quote:

Originally Posted by bigshot 

Good sound isn't about perfecting the last 1% or 2%... That's the realm where expectation bias rules the roost. Good sound is about driving the bugs out of the 98% or 99%. It is a LOT harder than it seems to do that. It's so hard, a lot of people don't even bother to address it. They put their faith in high price tags and fancy sales literature and piddle away their energy worrying about things that just don't matter.

Another aspect is whether that last 1-2% is worth caring about. You can think about using 128 bit precision to get as close to analog as possible and reduce quantization errors, but if it doesn't make a dime's worth of a difference, its no use.

This is the whole gist of design. Everything is designed to a specification. And the specification is made on the basis of an established phenomenon.

I mean, given the money and time, someone can definitely come up with this, with a million dollar price tag, but if it doesn't matter, it doesn't matter.

Another common example would be the iPhone retina display. Would you notice if I make it twice the resolution at the same size? The answer is no, and hence its not worth the extra processing and graphics power it would require.

Quote:

Originally Posted by proton007 

 

Another aspect is whether that last 1-2% is worth caring about. You can think about using 128 bit precision to get as close to analog as possible and reduce quantization errors, but if it doesn't make a dime's worth of a difference, its no use.

This is the whole gist of design. Everything is designed to a specification. And the specification is made on the basis of an established phenomenon.

I mean, given the money and time, someone can definitely come up with this, with a million dollar price tag, but if it doesn't matter, it doesn't matter.

 

Another common example would be the iPhone retina display. Would you notice if I make it twice the resolution at the same size? The answer is no, and hence its not worth the extra processing and graphics power it would require.

This is a good point, along with the one bigshot made - if something is so insubstantial that it can't be reliably discerned then it probably isn't worth spending money on, especially when there are other more tangible things competing for the same money.  With my equipment I would say that USB cables and software buffer size would both fall under this category, it is a strain to tell the difference.  Other changes I have mentioned like bit depth and processor scheduling are a little more obvious from memory, but I would really need to test them again to quantify how much of a difference they make, and these variables are relatively easy to toggle.  I *think* I would be able to DBT bit depth, I would just need to come up with a methodology, and again this is not directly related to USB cables.  I will have to get back to you on that one.

The reason I pursue some of these things is because 1-2% is not much by itself, but add up several such minor changes and soon enough there may be something more significant like a 5-10% difference, plus playing around with these settings is free so no harm is done to the wallet.  Unfortunately I have tried some audiophool tweaks that are very much not free and also very much rubbish components that made the sound worse.  

I try to warn people about these as much as possible, but the whole subjectivity thing means many people hear an improvement when the change is actually negative - it is easier after all to create an audible difference by making something worse than it is to make an audible difference by making something better, I think a lot of audiophile companies know this and exploit the subjectivity of audiophiles.  Considering this it is probably wiser to stay away from audiophile tweaks, especially really dodgy sounding, tenuous and yet also expensive tweaks.

Quote:

Originally Posted by dvw 

You are talking about packet jitter rather than timing jitter I assumed. With packet jitter, the difference can be solved by the buffer unless the latency is extremely large, then you might have buffer overrun or underrun. In either case, this will result in skipped sound or pop corn noise.

Yes. Buffer underrun is probably a more common gross issue due to PC neglecting it's USB duties.

However, in the minutiae aspect of audio thingies, if the DAC clock is somehow derived from the source (PC) then some likely small amount of timing jitter could make it's way to the DAC buffer reads... Likely this jitter is measurable, but perhaps inaudible. Some examples of DAC jitter characterization:

http://www.stereophile.com/content/abbingdon-music-research-dp-777-da-processor-measurements (fig. 24)

http://www.stereophile.com/content/bel-canto-eone-dac35vb-da-converter-measurements (fig. 9)

http://www.stereophile.com/content/rega-dac-da-processor-measurements (fig.15)

A very clean one using asynchronous mode:

http://www.stereophile.com/content/halide-design-dac-hd-da-converter-measurements (fig. 10)

I have a Total BitHead DAC/Amp which seems to suffer from jitter a little more than the previous examples (probably since it's an older design):

http://www.stereophile.com/content/headroom-total-bithead-headphone-amplifier-measurements (fig. 12)

I can't say the jitter was clearly audible. Maybe it would manifest itself as some sort of distortion... I could see there might be better DAC/Amps out there in terms of measurable performance at the very least.

To me, however, the long pole in the tent is the headphone itself, and USB cables are next to non-issue.

By now I feel this thread has run circles a few times already....what do you guys think?

Quote:

Originally Posted by proton007 

By now I feel this thread has run circles a few times already....what do you guys think?

I probably am [running circles] anyway  It's good exercise right?

Quote:

Originally Posted by proton007 

By now I feel this thread has run circles a few times already....what do you guys think?

LOL! It has indeed.... But I guess...

Quote:

Originally Posted by bigshot 


For some reason, few people understand my point. I'm not saying that 1 or 2% is too small to bother with. I'm saying that too many people who worry about small issues *haven't even dealt with the big issues yet*.
It's easy to buy another cable. It isn't easy to achieve a flat frquency response. I am quite sure that the number of people around here employing precise equalization is very small. Also, what's the point of worrying about the "sound signature" of a simple wire when you're listening to hot mastered music with loads of added distortion effects? Maybe better recorded music would help. How many people looking to upgrade the sound of their $800 headphones make the obvious upgrade- to speakers?
These are all things that improve sound to a degree that you don't need measurements or double blind testing to discern. There is absolutely no reason to worry about the little stuff until you've dealt with these issues. The most expensive cabling in the world won't make the Red Hot Chili Peppers' miserably engineered albums sound good. And modding your amp won't help if you haven't EQed to flatten out the bass hump and high end spike in your cans. And even if you've taken care of all that and have a great headphone rig and well engineered music, a good speaker system will blow the pants off it when it comes to soundstage and presence.
Just swapping cables looking for placebo improvements is a complete waste of time. Jitter is inaudible. bringing it up over and over "for the sake of completeness" only misleads people into thinking it matters. it doesn't. not even a little bit. Great sound is about the big things, not the tiny ones.

My impression of the last 1 to 2 % improvement quoted by some people actually means if I spent more money, I can reach the pinnacle of "audiophiledom". This has absolutely no relationship to quality. The key qualifier is the color. How can there be color in a 100% fidelity system? By definition, 100% fidelity systems will sound exactly the same. This fact also contradicted the audiophile notion that everything has a signature sound even cable and they sound all different. It's like people are making their own instrument instead of listening to one.

IMO, the last 1 or 2% is not achievable. I have heard some awesome systems but there is none that I will mistake for a live performance. Perhaps it's in the recording or the setup. Or I may need to do a live DBT. Any way, I can always tell if it's live or if it's Memorex.

Agreed.

Also, to me the closest to live performances has been binaural recordings (through headphones)... Like you said, certain improvements may require setup/recording infrastructure changes. Then there is the loudness wars.

Quote:

Originally Posted by bigshot 


For some reason, few people understand my point. I'm not saying that 1 or 2% is too small to bother with. I'm saying that too many people who worry about small issues *haven't even dealt with the big issues yet*.
It's easy to buy another cable. It isn't easy to achieve a flat frquency response. I am quite sure that the number of people around here employing precise equalization is very small. Also, what's the point of worrying about the "sound signature" of a simple wire when you're listening to hot mastered music with loads of added distortion effects? Maybe better recorded music would help. How many people looking to upgrade the sound of their $800 headphones make the obvious upgrade- to speakers?
These are all things that improve sound to a degree that you don't need measurements or double blind testing to discern. There is absolutely no reason to worry about the little stuff until you've dealt with these issues. The most expensive cabling in the world won't make the Red Hot Chili Peppers' miserably engineered albums sound good. And modding your amp won't help if you haven't EQed to flatten out the bass hump and high end spike in your cans. And even if you've taken care of all that and have a great headphone rig and well engineered music, a good speaker system will blow the pants off it when it comes to soundstage and presence.
Just swapping cables looking for placebo improvements is a complete waste of time. Jitter is inaudible. bringing it up over and over "for the sake of completeness" only misleads people into thinking it matters. it doesn't. not even a little bit. Great sound is about the big things, not the tiny ones.

Very good point, hard to argue with.

Quote:

Originally Posted by dvw 

My impression of the last 1 to 2 % improvement quoted by some people actually means if I spent more money, I can reach the pinnacle of "audiophiledom". This has absolutely no relationship to quality. The key qualifier is the color. How can there be color in a 100% fidelity system? By definition, 100% fidelity systems will sound exactly the same. This fact also contradicted the audiophile notion that everything has a signature sound even cable and they sound all different. It's like people are making their own instrument instead of listening to one.

 

IMO, the last 1 or 2% is not achievable. I have heard some awesome systems but there is none that I will mistake for a live performance. Perhaps it's in the recording or the setup. Or I may need to do a live DBT. Any way, I can always tell if it's live or if it's Memorex.

I think the "sound signature" or coloration is often seen as a means of covering up another flaw in a system or bad recordings etc.  Some people like a bit of bloom in the sound, and strangely some digital audiophile tweaks IMO can provide this, but it is not actually higher fidelity from an objective perspective.  Some forms of distortion seem to be more bothersome than others, even at levels which would not otherwise be considered significant.  A couple of videos that are mildly relevant to these concepts:

Borrowed a very expensive USB cable this past week to try in my big rig at home.  Source is a Mac Mini > Pure Music (Integer mode) > Ayre QB9.  I had been using the cable that came with the QB9.  As much as I hate to admit it was a huge step up in performance - much greater transparency that allowed much more musical nuance to come through.  Using the expensive cable, playing Emmylou Harris's Boulder to Birmingham (Producer's Cut 24/96), her emotion comes thru in the music and hits hard.  And the QB9 runs asynchronous transfer mode, so you wouldn't think USB cables should change the presentation.

Of course all good things must come to an end - cable has to be returned tomorrow.  Took it out the system and put in the old.  Decided to play Boulder to Birmingham one more time.  All that sense of emotion was gone....

Before you flame.  Went upstairs to talk to my wife who was in bed in another room.  First thing she said:  Something changed - the song didn't sound nearly as good the last time you played it.  She didn't even know I had a borrowed USB cable in the system.  Wasn't a DBT, but it certainly was a blind test....