This is not what’s being hypothesized, though. Everyone seems to be in agreement that digital errors are not occurring (i.e. “the ones and zeros are the same either way”). The argument for cables influencing the sound is the opposite of this. That even in the absence of digital errors the underlying analog activity can somehow change the audio output of the DAC.
If no digital errors are occurring then by definition whatever analog activity is taking place falls within the normal and expected operation specifications of the cable/medium.
USB 2.0 is specified to have a bit error rate of no more than 10E-12 (ten to the minus twelve). Any USB connection that has a higher BER is out of spec and hence defective. Copying to a USB Harddisk would become a hit and miss process, if this spec would not hold in reality.
With a signal of 24bit/96kHz that BER would amount to one bit error every 1’206 hours. It is highly unlikely that after >1k hours of listening you will notice 1 bit wrong.
If the “analogue” noise causes more errors than that (which would need to be the case to give the claims raised here any plausibility) then the system is not designed to meet specs.
This does NOT mean that analogue noise cannot propagate along a USB cable and influence analogue circuitry in the equipment further down the line. But the disturbance is certainly not caused by digital errors (again, unless the equipment is faulty).
Jeez, people. Don’t focus on one point in text. The point of the text was to show that the digital data is transmitted using an analog signal and that analog signal can cause problems. That signal has noise associated with it. That noise includes electrical noise. I have stipulated MANY times that USB gets the digital data where it needs to go in bit perfect form 99.99% of the time. You need to stop focusing on the digital data alone. There is a lot more going on behind the scenes that just the digital data get from point A to point B.
The USB receiver has to work harder when the analog signal is not as good as it could be. The eye pattern of USB can be right on spec, on the edge of spec, or even be out of spec and still deliver digital data perfectly. There can be very little electrical noise or a lot of electrical noise and the digital data can still be delivered perfectly. Just because the digital data gets delivered perfectly in virtually all cases does not mean the USB receiver and associated hardware are doing the same work or passing the same noise or lack of noise deeper into the DAC.
On scopes, I have seen USB eye patterns that look very different on a system sending the same data. The only change was the USB cable. Different cable characteristics change the eye pattern which changes was the USB receiver sees, how it has to work, and what it might pass on to the rest of the DAC circuitry.
Probably because the emperor does not want to risk being seen naked in public.
AJ
4 Likes
James_I
(The truth is out there but not necessarily here)
66
Hey Speed - this is the kind of data that the objectivists, or rationalists, have been demanding to see. I suggest that you back up that statement with actual eye pattern data with different cables. That, actually, is something that could take this thread (and frankly the whole bits are bits argument, at least USB-wise) to a different level.
I do not get the impression that he actually works with oscilloscopes. Nor do I. (When I do signal analysis, it is not time domain but primarily RF frequency domain – if that matters).
However, he has seen oscilloscope eye patterns published. Me, too. The key then is interpreting those eye patterns.
Not purely USB but USB to S/PDIF, examine these published eye patterns:
Now, setting aside any potential jitter – not relevant to asynchronous USB nor Ethernet – which eye pattern indicates superior demodulated signal recovery?
Actually, James, what the objectivists would like to see is a measurement of the audio signal coming out of the DAC. There is no evidence that a difference in eye pattern causes analog differences.
In fact some people (ASR, Archimago) do this. The important point in their measurements is that they don’t claim to be able to make a measurement that shows which signal is better, just that if we make two measurements with two different cables and there is no measurable difference in the analog signal, then either (a) the cables had no effect on the audio signal, or (b) we are not able to make meaningful measurements of analog systems. Thus, in order to maintain that these cables make a difference we must throw out the entire engineering edifice.
Before the Roon forum software automatically deletes the quoted post above, let it be known that the thrust was a British hi-fi magazine series of eye pattern test bench measurements — all almost immeasurably similar. That should not be terribly difficult to track down,
Why Tony withdrew it, I do not know. I do not approve of the ability to withdraw and delete posts — post hoc — in this community. If you post it, you own it. And no hiding behind new or changed usernames.
Maybe that is the key to you. It isn’t to me. The key is that the patterns are different. Which means what the USB receivers sees is different and that difference has the potential to cause there to be a difference downstream from the USB interface in the DAC.
You are so caught up in being precise that your are ignoring the point of what is being said. All y6ou want to do is try and diminish what I say with veiled insults like “I do not get the impression that he actually works with oscilloscopes.” You know what you can do with those insults…
I withdrew because I could only post a pdf off-print rather than a link. I had never posted a onedrive link here before and was surprised at the amount of personal information in the directory structure of the link so I withdrew it rather than figure out how to post smarter. There is probably a way for me to do this more directly but these eye-patterns were once much discussed in Hi-Fi News. So it was not difficult to find links on other forums. Here are two links to off-prints of group tests on Pg 22 of an old thread in Audiophile Style. Just to be clear I had originally posted the first link.
Edit. I forgot to mention. It was on the basis of the link to the 2013 group test that I bought (online and sight unheard) the relatively inexpensive (in context) Chord SilverPlus. I never felt the need to change it but I only had a 0.5m length. To cut a long story short I recently had a temporary need for a longer USB length so I bought a cheap grey 1.8m belkin at the local computer store. I was really surprised. I was expecting otherwise, but in my system I really couldn’t hear a difference.
But what evidence do you have that this difference has any effect whatsoever on what comes out of the DAC? Do you actually have any data that shows this?
If you ever want some some good laughs, www.wathifi.com is comedic gold.
I just find it hilarious how audiophiles believe our ears are so finely tuned that we can hear such minute changes that even computers can’t detect. Even more hilarious is how some of the leading experts we trust are both: a. old and as such have deteriorated hearing due to aging and b. have been to many concerts themselves and surely have some level of hearing damage.
I’ve just replaced my Chord Signature Super ARAY, with the Chord Sarum T Super ARAY USB between my endpoint and my DAC. The chain is as follows:
Stack Audio LINK & SA Linear PSU => Chord Sarum T Super ARAY USB => Chord Hugo M Scaler => Atlas Mavros Digital Dual BNC-BNC => Chord Hugo TT2 => Chord Sarum Super ARAY RCA => Linn Klimax Kontrol => 2 x Linn Majik 4100 (Aktiv) => Linn Majik 140 (Aktiv) + Linn Majik 126.
but if it sounds great to you THAT is all that matters - and that you are not really breathless 
