USB cable and Sound Quality - Page 22

The cable issue really isn't an issue except with commissioned stereo salesmen and internet "know-not-quite-enoughs". Most audio professionals and experienced hi-fi nuts know the score.

Audiophile cables may be one of those products that if you have or haven't tried, either way you won't know what you are missing.

Edited by ultrabike - 8/23/12 at 1:06am

As long as recording studios continue to use normal, cheap, cables to record the music I'm listening to, I won't be investing in anything more expensive.

 

"Cable enthusiasts" are welcome to indulge their habit just like anyone else, but they shouldn't encourage others who aren't adept at critical thinking.

To be fair, some studios do use expensive cabling. What is unclear is what drives most the specific decisions. The majority of the engineers I have worked with are very adamant about balanced wiring for long cable runs (makes sense) but they could care less who makes the wires (or what material). They are worried about the physical and measurable factors... not the woo woo. 

 

But there are a few outliers out there that have bothered with some of the more esoteric cable blends - sometimes driven by a belief that if offers a real benefit, sometimes for the bragging rights of saying they are using X-brand cabling as part of their marketing, sometimes because the cable makers have provided the cable so that they can claim X-studio uses theirs exclusively.

 

It's a weird world we live in. 

I've worked with a bunch of great sound houses in Hollywood. I actually asked a couple of Head Engineers what they used. They buy great big giant spools that they get at the pro audio supply equivalent of monoprice.

The few that use high end cables have a licensing agreement and fee for their name to be used in marketing I'd wager.

I'm sure some of them drink the koolaid.  To be honest though I don't see why they would use USB in preference to Firewire if the equipment supports it (apart from the cables using more conductors and therefore costing more...)

 

Some audio production people are pretty deep into the digital tweaks - they probably have not done blind testing but honestly some differences do not warrant it such as newly soldered cables sound way too warm and smooth at the start, but IMO this is some sort of distortion.  Either way I am sure anyone could hear this, only problem is you need to mock up a new USB cable each time you want to test this, and this will probably vary depending which factors contribute to this initial warmth.  Also how would you control the variables, each cable would need to be tested empirically etc. it's a bit of a long shot.  Would be interesting to look into anyway if I have time to terminate some factory produced cable I have my eye on.  I wonder how much of the "wow this cable sounds so different" is due to some sort of similar effect with new cabling...

 

This initial performance may or may not be indicative that the cable is operating within USB spec, and this is difficult to prove unless one has an oscilloscope to test DIY cables for characteristic impedance.  If this were to occur on something like a monoprice that might be different but from what I have seen they are fairly sensible with the solder connections.  I would not recommend their round SATA cables though - they made my computer unstable - maybe not as tight control over the impedance as the flat SATA cables.  They look quite a mess inside in terms of the geometry, shielding drain wires etc.  SATA of course is operating at a much larger frequency range, and yes generally most cables that are within spec will work.  I might need to do some benchmarks to see if there are any differences that can be verified (and maybe get me my $2.50 per cable back lol).  I did recheck that cables were seated properly but in the end I needed to put the flat cables back in to bring the system stability back to normal.

 

An intersting case study might be CAT5/6 as these also share 100 Ohm characteristic impedance, but no doubt over a much lower frequnecy range than SATA, also designed to be used in a much lower noise environment etc.  Actually a few buotique labels jumped on the  network cable market, but I wonder how they stack up against a standard CAT6 cable, or how these would supposedly make a difference unless they are being used as I2S interconnects...  I would hate to think how much 15 meters would cost   As I mentioned earlier I think the fact that many boutique cables are sold in such short lengths is a way of cheating with the performance.

 

On the pro-audio cable  thing though a colleague of mine said that he compared some unnamed buotique coax cables and they performed worse than Belden, I think he commented that the boutique brand actually performed badly...  Having said this I don't think it is logical to deduce from this that all boutique digital cables are rubbish, just that they are an unknown quantity as they do not publish specs.  They are quite a big risk because of this as well as the fact that what people consider to sound "better" is not always better performance in my experience.  The pro-audio cabling with published specs and proper engineering is a much more prudent investment, and no doubt this is why many studios use these brands.  People are right to be suspicious anyhow.

 

What is perhaps more damning though is that some companies publish specs for some cables and not for others, or publish some specs but not anything as extensive those published by Belden etc.  One does wonder what they have to hide.  Maybe people like the sound of poor measured performance, maybe the specs are just pretty ordinary?  It's hard to say until somebody measures these things properly.  

When it comes to cables, none of the engineers I spoke with cared about sound. They only cared about durability. They wanted to know that if they spent a few weeks wiring a mixing board, it wasn't going to short out anytime soon.

 

+1000

 

With the exception of susceptibility to EFI noise or crosstalk over long runs, etc. 

Well; I used to work in the standard body that decide the spec. The deciding factors are EMI, BER, distance and cost. CAT5/6 cables needed to be backward compatible that's why they're 100 ohms. They also need to be 100 meters in length. This is why there is a difference in length and speed between protocol. This has nothing to do with cable quality but more with law of physic and what can be achieved at a reasonable cost. I will challenge any body that can make a USB cable to go 100 meters. Boutique cable will not have better performance than a standard compliant cable.

 

Imagine this, if indeed cable can enhance or degrade quality of music, people will be complaining about the music they bought. Bittorrent will no longer exist. There will be audio grade phone wire and audio grade DSL services. Why would a source music downloaded from 30/40 year old skinny phone wire sound better through a boutique USB cable?

To be fair the phone wire had 30 or 40 years of  burn-in.

Downloading a music file just depends on overall error correction, it isn't quality-dependent on timing accuracy and electrical noise isolation like playback of that file can be. So the debate goes anyways.

yes. But how does timing accuracy affect better bass, more detail and better sound stage. How is timing affected by USB cable? Let's assume, there is a 1 ns jitter. Does this mean USB 1.1 performs better than USB3 because percentage is lower? Let's further assume the clock is derived from the USB. How is that related to the recording clock? I mean assuming the sampling clock is 44KHz +/- 1 KHz. My recording clock is 43KHz. How does the USB send out this clock? If I am sending one track after another, one has a 43KHz clock and another has a 45KHz clock. Does the USB clock actually change? How does this impact the other devices on the bus? 

 

Personally I don't think the same argument on SPDIF works with USB.

Wouldn't minute timing errors affect high frequencies where the waveform is all bunched up, than low frequencies where the waveform is five feet long?

The only timing error came from the jitter when you have too much coffee. The sound stage seems smaller when you're pacing on it. This is not the right time to measure the sound stage.

 

I'm not sure but I think HiFace describe the transfer mode they use as bulk mode, although I'm not sure how this applies specifically and it probably varies depending on the driver in question.  This is an interesting question though as it does throw into question a lot of the assumptions regarding how USB cables might affect jitter in USB audio.  I can say that my personal non-controlled experience with the battery modified HiFace I was using that USB cabling (especially length with very short cables eg <10cm) did still affect the sound for better or worse, and that was completely powered from battery, and presumably doesn't care much about the timing of incoming data as it uses batch mode with some sort of hardware buffer.  It would be interesting to find out how many samples are sent in each USB transfer packet, but I have my doubts that the driver designers will be willing to disclose this information.  Are there any open source USB audio driver projects??.  Knowing what I know now though, maybe too short cabling may have made signal reflections worse but I guess it is hard to say without testing.