[Brooko]

And again - you go toward your circular debate - which is a real pity.  Whether this is intentional or not does not matter - it is happening.  Avoidance still gives the same result.
 
So at this point I will simply unsubscribe.  There is little point me being here.  If you are unwilling or unable to follow up your theory with meaningful data, then I would suggest all people on this thread do the same.  It would then make my job as a Moderator much easier too.

 

[castleofargh]

mmerrill, the simple idea of saying to objective people that "current measurements won't show any difference considered audible"... surely you must understand how messed up it feels.
 
at this point you could be saying that measurements aren't as good as your ears, or that you would be measuring the wrong thing(indicating that you made up the wrong theory to explain the change in sound, if real). or that somehow the consensus on hearing threshold of that particular spec is erroneous.
those seem to be the logical possibilities implied by your post. first one has a clear answer as we can measure so much more than the ear can perceive. second one is more and more what my gut feeling is telling me to accept, third would require sooooo much work for you to demonstrate it that I doubt we will ever get a result, so bringing it up while knowing you don't have the means to prove it, too much confidence not enough facts. not science.
 
about doing a blind test, to me it would demonstrate an audible difference in sound. that would be something of course as we can then remove the "he dreamed it all" possibility that so far you haven't been able to exclude TBH. but that would not demonstrate superiority of one of the 2 sounds, only an audible difference. and it would certainly not demonstrate your theory as long as we don't have objective data on all that is changing on a given system when using the intona. so yeah we go in circle because you have no data. and nothing to confirm a hypothesis, which IMO would be more fitting instead of theory in Keith's post if we're talking science. but I misuse the words all the time myself because of how they don't mean the same thing inside and outside of science(whyyyyyy?????!!!!!!).

 

[mmerrill99]

And again - you go toward your circular debate - which is a real pity.  Whether this is intentional or not does not matter - it is happening.  Avoidance still gives the same result.

So at this point I will simply unsubscribe.  There is little point me being here.  If you are unwilling or unable to follow up your theory with meaningful data, then I would suggest all people on this thread do the same.  It would then make my job as a Moderator much easier too.

I'll make it easy for you by unsubscribing myself - I have said all I need to say. Perhaps when one of you hear an Intona or similar USB isolation device you might remember this thread?

BTW, it just occurred to me, that when a thread is titled as this one "Why USB cables can make a difference" it calls for speculation. Nowhere do I see that posts have to provide "proof/evidence" that the speculation is actually correct - it wouldn't be speculation then would it?

 

[BiggerHead]

I'm referring to non-linearity to mean non-linear distortion where two or more signals at different frequencies interact to form intermodulation distortion. If you take away one source of the the signals, the IMD disappears. In other words we have the audio signal set of frequencies & we have a separate source of signals at another frequency - the noise (probably at RF frequencies?) With no audio signals present the RF noise has no audio signal to mix with to cause any audible issues. Introduce the audio signals & we have IMD which can be audible. Take away the RF noise & we have no IMD, just the audio signals.

How most audio analogue deals with RF noise is much too complicated to fully understand but I'm pretty sure that the above scenario applies. One of the biggest culprits are the opamps used on the outputs of DACs for I/V duties. All current output DAC chips output out of band RF noise & most voltage output DAC chips have in-built opamps.

 
What do you think non-liearity means?  It means a system where the output is not a proportional sum of its inputs.  This distortion you describe comes BECAUSE of that. Now my example is oversimplified as derivatives, hysterisis, and thus frequency can enter in, but it doesn't change the fact that I don't see how you can produce a -80 db distortion from 0db tone as a result of adding a -100db noise and still have an amp capable of playing music. If it does this adding -100db to a tone what does it do when adding another tone, say -10db to the primary tone?  You'll get garbage.  I mean you're talking about distortions are that are larger than one of the signals that generates them.  You will have chords generating extra effects louder than the chord iteself! 
 
Anyway, the math of this stuff is well laid out so if you can find a mechanism to do that without ruining music, I'd love to be proven wrong here. In the end though sound is driven by power not math, and power is supported by actual volts.  These distortions don't live in some mathematical ether.  They are real voltage fluctuations coming from how the amp responds to the signals.  If a .0001%   variation in input on your amp is producing  .001% output fluctuations, your amp is junk, not in an audiophile sense, in a "it's not an audio amp" sense.

 

[DangerClose]

When I used the ferrite compound USB cable I heard a very similar change in the sound as when I used an Intona USB isolator with a standard USB cable. Hence my hypothesis

Were they good changes in sound, or bad changes in sound?
 
If two USB cables are the same except one has an inch-long ferrite module section in it, which one to get to connect PC to DAC?  
 
I don't know if such a thing even matters for USB, but I've heard enough changes from audio cables to have an open mind about USB cables. 

 

[GRUMPYOLDGUY]

With digital cables the goal is to reduce BER. This is influenced by a number of parameters, the biggest (and easiest to fix) is noise due to EMI. The differential signaling definitely does a lot to improve signal integrity by eliminating common mode noise from the equation. Other things you can do to help are make sure you have a properly shielded cable and use things like passive filtering and ferrite cores to further reduce high frequency interference. I would suggest putting the filtering and ferrite bead closer to the PC. I'm not positive it matters where in the chain you put it, but intuitively I would put it at the beginning. Maybe someone who's more familiar than me with analog behavior can chime in on this.
 
And for what it's worth... CRC might be part of some higher level protocol for USB transactions, but electrically bit errors can occur. And, for example, I could design a USB slave interface that doesn't care about CRC calculation and just accept the bit errors. Whether or not manufacturers do that is a different question. I for one would opt for higher bandwidth on the bus and put the onus on the user to make sure cabling is sound. Bit errors can cause artifacts in the samples being pushed across the bus, which may or may not be audible. That argument is a rabbit hole I really don't care to go down. But if you can make your system more electrically sound, why wouldn't you want to... regardless of whether or not it makes an audible difference? 

 

[spruce music]

 
With digital cables the goal is to reduce BER. This is influenced by a number of parameters, the biggest (and easiest to fix) is noise due to EMI. The differential signaling definitely does a lot to improve signal integrity by eliminating common mode noise from the equation. Other things you can do to help are make sure you have a properly shielded cable and use things like passive filtering and ferrite cores to further reduce high frequency interference. I would suggest putting the filtering and ferrite bead closer to the PC. I'm not positive it matters where in the chain you put it, but intuitively I would put it at the beginning. Maybe someone who's more familiar than me with analog behavior can chime in on this.
 
And for what it's worth... CRC might be part of some higher level protocol for USB transactions, but electrically bit errors can occur. And, for example, I could design a USB slave interface that doesn't care about CRC calculation and just accept the bit errors. Whether or not manufacturers do that is a different question. I for one would opt for higher bandwidth on the bus and put the onus on the user to make sure cabling is sound. Bit errors can cause artifacts in the samples being pushed across the bus, which may or may not be audible. That argument is a rabbit hole I really don't care to go down. But if you can make your system more electrically sound, why wouldn't you want to... regardless of whether or not it makes an audible difference? 

Bit errors over USB are a complete non-issue.  A non-issue with a $3 USB cable.  The errors almost do not occur with audio over USB. 

 

[GRUMPYOLDGUY]

Almost isn't good enough for me.

But yes, you're right that signal integrity in such a simple setup and relatively clean environment is almost never an issue.

But the general question in this thread is what impact can a USB cable have on audio. The answer is data transport, and specifically signal integrity. BER being the key metric.



Sent from my E5803 using a highly trained, special forces carrier pigeon

 

[spruce music]

Almost isn't good enough for me.

But yes, you're right that signal integrity in such a simple setup and relatively clean environment is almost never an issue.

But the general question in this thread is what impact can a USB cable have on audio. The answer is data transport, and specifically signal integrity. BER being the key metric.



Sent from my E5803 using a highly trained, special forces carrier pigeon

Okay then how much data integrity is enough?  There have been plenty of tests where hours and hours of audio were sent over USB without one single error.  Not one.  Such errors if they occur result in an obvious tick or pop sound.  They do not add up in small numbers to slightly alter sound quality.  The whole idea boutique USB cables are about errors is wholly and completely, demonstrably, and thoroughly tested as simply WRONG.  Once you get that you might start to understand.
 
Has some USB cable lost a bit or something at some point in history? yes.  Using USB for audio it will usually be hours upon hours upon hours (and might be never) when a listener experiences an error in transmission.  When it happens it will disrupt sound for a fraction of a second and that is all.
 
So you need to get comfortable with the idea you were mistaken, and when the idea is such cables reduce errors just realize it is NOT so.
 
Now almost never is not good enough for you?  So if something works completely perfectly 99.9999999999998 % of the time, and by spending 100-1000 times the money to make it 99.9999999999999% does that make you think your resources were well allocated?  Remember also when that low chance of error occurs it results in a fraction of a second disruption and otherwise impinges on sound quality not at all.  Also remember the higher priced alternative has shown no evidence it actually will help with this issue.  Finally remember USB audio data transmission is generally more reliable than the percentages I have typed in by a few orders of magnitude.

 

[GRUMPYOLDGUY]

Settle down tiger.

It depends on which bit in the word is flipped. If something close to the MSB is flipped, it will be more audible than if the LSB is flipped. As to whether or not this error which lasts for 1/44100 of a second or less is audible, to me is irrelevant. I'm going to do everything I can to create the best electrical environment for my equipment. Period.

That fraction of a percent may be irrelevant you, it's not to me. You have to decide what is the best use of your money.

If you think digital transport has anything to do with something other than gettings bits from A to B, then you are "simply WRONG".



Sent from my E5803 using a highly trained, special forces carrier pigeon

 

[spruce music]

Settle down tiger.

It depends on which bit in the word is flipped. If something close to the MSB is flipped, it will be more audible than if the LSB is flipped. As to whether or not this error which lasts for 1/44100 of a second or less is audible, to me is irrelevant. I'm going to do everything I can to create the best electrical environment for my equipment. Period.

That fraction of a percent may be irrelevant you, it's not to me. You have to decide what is the best use of your money.

If you think digital transport has anything to do with something other than gettings bits from A to B, then you are "simply WRONG".



Sent from my E5803 using a highly trained, special forces carrier pigeon

All you have to do is show us how often any bits get flipped.  Effectively it doesn't happen.  Actually it happens not more often than once every few dozen billion bits.  Sound quality of USB cable isn't about bit errors.  For that matter it isn't about sound quality.  Cheap USB cables do everything you need for them to do.  So after determining how often cheap USB cables flips or loses a bit you then have to show some other more expensive cable does it less often.  I will posit the 1st step happens so rarely you will struggle to have a chance to show the second.

 

[GRUMPYOLDGUY]

As I said, it depends on the conditions. If I drag the USB cable through a bunch of power cords behind a desk, it will be more prone to bit errors than if it's the only cable present with no EMI to worry about. The latter case likely has almost no errors.... Until the cable starts to fail from wear.

You keep talking about sound quality... Why? How many times have I said I don't know whether or not it makes an audible difference, and I don't care?

Here's what I think is different between a cheap USB cable and a more expensive one. Quality of assembly, isolation and shielding. I expect a more expensive cable to not have cold solder joints, to not have unnecessarily long sections of wire stripped back from isolation and shielding, and to not have unnecessarily long sections of conductor exposed. I expect the jacketing and connector to be more robust and less likely to fail under normal stress. I expect better dielectrics to be used for improved isolation. I expect better quality shielding to be used through the length of the cable.

I don't need to prove that the above contributes to better signal integrity. This is textbook stuff.

Sent from my E5803 using a highly trained, special forces carrier pigeon

 

[spruce music]

As I said, it depends on the conditions. If I drag the USB cable through a bunch of power cords behind a desk, it will be more prone to bit errors than if it's the only cable present with no EMI to worry about. The latter case likely has almost no errors.... Until the cable starts to fail from wear.

You keep talking about sound quality... Why? How many times have I said I don't know whether or not it makes an audible difference, and I don't care?

Here's what I think is different between a cheap USB cable and a more expensive one. Quality of assembly, isolation and shielding. I expect a more expensive cable to not have cold solder joints, to not have unnecessarily long sections of wire stripped back from isolation and shielding, and to not have unnecessarily long sections of conductor exposed. I expect the jacketing and connector to be more robust and less likely to fail under normal stress. I expect better dielectrics to be used for improved isolation. I expect better quality shielding to be used through the length of the cable.

I don't need to prove that the above contributes to better signal integrity. This is textbook stuff.

Sent from my E5803 using a highly trained, special forces carrier pigeon

If a $3 cheapo cable works without issues, then all of the other stuff you list is gilding the lilly.  I have tested just such things including winding one thru a nest of power cords and more.  Hours of such tests resulted in not one single bit error.  Could better isolated cables be built?  Sure.  Would it help your situation with regards to data integrity?  One might find such a situation, but in general the answer is no you won't benefit whatsoever.
 
If you want a nice cable with a bit more heft in construction try the Belkin Gold line.  It is more than $3, but not too much more.  $9  for 6 feet.  Has extra shielding and care of connector construction for strain relief.   Lifetime warranty.
https://www.amazon.com/Belkin-Gold-6-Foot-Cable-DSTP/dp/B00004Z5T2/ref=sr_1_3?ie=UTF8&qid=1472256374&sr=8-3&keywords=usb+cable+belkin+gold

 

[GRUMPYOLDGUY]

If you want to spend $9 on a cable, and that's good enough for you, then great... More power to you.

I'm not sure how this topic devolved from explaining how a USB cable *could* impact a system to attacking my purchase decisions. I'm not taking part in it anymore.

Bottom line is that a good USB cable will yield better signal integrity and fewer bit errors. What constitutes "good enough" is subjective... Make your own purchasing decisions. But everything I have stated is technically sound.



Sent from my E5803 using a highly trained, special forces carrier pigeon

 

[spruce music]

If you want to spend $9 on a cable, and that's good enough for you, then great... More power to you.

I'm not sure how this topic devolved from explaining how a USB cable *could* impact a system to attacking my purchase decisions. I'm not taking part in it anymore.

Bottom line is that a good USB cable will yield better signal integrity and fewer bit errors. What constitutes "good enough" is subjective... Make your own purchasing decisions. But everything I have stated is technically sound.
 

What constitutes bit errors is not subjective I will needlessly point out.
 
If $9 takes care of bit errors, one can spend more for any number of subjective reasons like color, the warm fuzzies of teflon insulation, technically excessive gilding the lilly so on and so forth. One will still not hear any benefits as one is not hearing bit errors as it is because one is not getting those errors.  
 
Oh and for what it's worth, adding ferrite cores to a properly designed and functioning USB cable has been shown to cause some errors to appear.  Another one of those technically sound gilding the lilly cases where in fact you hurt the functioning.