POLL: What USB cable are you using?

[JonP]

They only have to carry digital signals for a few feet at most. Digital is either on or off

 

Hi George,

 

USB cables don't actually carry a digital signal of "on" or "off". They carry an analogue signal of varying voltages. The reason why USB cables sound different is because in each system they are used, they contribute (add) to the overall level of jitter meaning that they add noise at varying frequencies at very low levels to the original audio signal (as do transports and DACs). It is this noise (and specifically how much noise and at what frequencies) which determines the sonic "character" of a USB cable. This can be thought in the same way that different dithering and noise shaping algorythms will sound different, even though the intended end result of this process is always the same - to reduce the word length of a 24 bit audio file to a 16 bits. Both processes (inserting a USB cable) and dithering / noise shaping will reduce the fidliety of the original signal because they add noise to it and that noise is not uniform either in terms of frequency or amplitude from setup to setup or cable to cable. The noise itself does not have to be audible in the same way that dithering adds noise below the auditory threshold, yet it changes the sound of what we can actually hear.

 

Jitter is caused by inaccuracies in the timing of the individual samples of a digital signal versus what that timing would be if all the clocking was literally perfect. It is critical in audio situations because it is a real time transfer and any variance from "perfect" will add noise. In data transfer protocols, none of these things are critical in practical terms and what you say is correct in this case (i.e that is either perfect or produces an error).

[Julf]

USB cables don't actually carry a digital signal of "on" or "off". They carry an analogue signal of varying voltages.

 

The important point is that that analogue signal is then turned back into a digital signal at the receiving end. So noise/distortion/whatever doesn't affect the bits - but the bit-to-bit timing, as you point out, can be affected.

 

The reason why USB cables sound different is because in each system they are used, they contribute (add) to the overall level of jitter meaning that they add noise at varying frequencies at very low levels to the original audio signal (as do transports and DACs). It is this noise (and specifically how much noise and at what frequencies) which determines the sonic "character" of a USB cable. This can be thought in the same way that different dithering and noise shaping algorythms will sound different, even though the intended end result of this process is always the same - to reduce the word length of a 24 bit audio file to a 16 bits. Both processes (inserting a USB cable) and dithering / noise shaping will reduce the fidliety of the original signal because they add noise to it and that noise is not uniform either in terms of frequency or amplitude from setup to setup or cable to cable. The noise itself does not have to be audible in the same way that dithering adds noise below the auditory threshold, yet it changes the sound of what we can actually hear.

 

Jitter only has an effect if the DAC doesn't use proper double buffering. Asynchronous USB does allow for proper double buffering that totally recreates the timing of the bits, making them totally unaffected by USB jitter.

 

Even if you don't use double buffering with independent clocks, I don't think it is accurate to describe the effect as "reducing word length from 24 to 16 bits".

[JonP]

I don't think it is accurate to describe the effect as "reducing word length from 24 to 16 bits".

 

I am not suggesting the effect is the same or that is is indeed the effect itself. I am trying to find a more accessible illustration as to how noise well below the audible noise floor in digital audio alters the sound we hear and how the distribution of that noise (i.e spectral analysis) changes the sound as that noise spectrum changes. The relationship I am trying to draw here is that jitter has different characteristics with different equipment combinations because the noise spectrum is different with different equipment and different cables. And in the case of dithering from 24 bits to 16 bits, noise is also added and the spectrum altered (by noise shaping).

 

In the absense of the ability to do real ABX testing in a system with different USB cables, experimenting with noise shaping 24 bit audio is neverthless (in my opinion) a viable and accessible method by which to get an understanding of the notion that noise well below audible thresholds - whether that be induced by software or induced by a USB cable - can and does change what we hear.

 

If one can be accepting that a 16 bit version of a file sounds different than a 24 bit version of the exact same file even when listening at an average level of 60dBA, in my view it then becomes a much smaller leap of faith to accept that if a cable changes the spectrum of jitter (which is often at similar levels to noise artifacts caused by reducing world length) then it too can arguably change the sound. That is all I am trying to point out here.

 

It would be far easier if people just went out to a dealer and asked that dealer to faclitate a blind test for them between a $5 USB cable and a high-end Audioquest or Wireworld cable. I do not see why any scrupulous, authorised dealer with a reputation to uphold would not oblige such a demonstration. It's not going to help their business to sell a $500 USB cable to someone who can't hear the difference between it and a Hewlett Packard printer cable (because in general terms people who feel they are ripped off are usually unhappy about it), yet dealers are obviously selling dedicated audio USB cables on a routine basis, even though for the most part, these dealers have approval schemes and return policies (even online dealers such as The Cable Company). Even if 99 people out of 100 cannot hear the slightest difference between those cables (and I have absolutely no idea what that figure might really be), it only takes 1 person to correctly state which cable is which say, 10 times out of 10, to illustrate that the cables do indeed sound different. In my view a lot of the USB / digital cable debate hinges around this concept. In stating as a fact that USB cables make no difference, it does not take into account that somewhere in the world, and perhaps in audio dealer showrooms on a daily basis - someone may actually have truly blind tested them in a robust test and picked which was which each and every time.

 

I do concede that USB cables may not produce audibly different results in some cases, but I for one cannot and will not ever state that as a fact, since I have not heard every DAC or every USB cable, let alone blind tested all the possible combinations. And even if I had, just because I might not hear a difference myself does not mean someone else with better hearing and more advanced listening skills might hear a difference. It would only take one person in the world to successfully ABX two different USB cables using "the most perfect DAC ever built" to prove this latter concept wrong as well (even if for example, 10,000 other people can't hear the slghtest difference). Afterall, the debate with regard to digital cables and USB cables in particular seems to be more along the lines that they simply cannot and do not make any difference at all, rather than what I consider the more plausible scenerio - that being they do make differences, it is just that a significant subsection of the human population either do not possess the listening skills and / or equipment to hear those differences or have already made their mind up without feeling the need to actually thoroughly investigate it for themselves by way of extended auditions carried out with an open mind.

[mav52]

All this talk about jitter:

I have yet to have jitter be made audibly present. I know it can be measured, but if you can't hear it, should you care?

[Julf]

if you can't hear it, should you care?

 

No, if you can't hear it, you probably should not care. There are enough audible things to care about.

 

(and I am not taking a position here for or against audibility, all I am saying is that if you can't hear it,

you can't hear it, and your time, effort and money is better spent on other parameters)

[The Computer Audiophile]

All this talk about jitter:

I have yet to have jitter be made audibly present. I know it can be measured, but if you can't hear it, should you care?

 

Hi Mav - Do you know what the audible effects of jitter are? What to listen for? What frequencies are most effected by jitter?

 

Many people think they are listening for jitter as a distinct item but jitter simply effects music frequencies and changes the sound.

[Julf]

It would be far easier if people just went out to a dealer and asked that dealer to faclitate a blind test for them between a $5 USB cable and a high-end Audioquest or Wireworld cable.

 

Agree.

 

Afterall, the debate with regard to digital cables and USB cables in particular seems to be more along the lines that they simply cannot and do not make any difference at all, rather than what I consider the more plausible scenerio - that being they do make differences, it is just that a significant subsection of the human population either do not possess the listening skills and / or equipment to hear those differences or have already made their mind up without feeling the need to actually thoroughly investigate it for themselves by way of extended auditions carried out with an open mind.

 

I can agree with that statement to a large degree, but my expectation is also that if USB cables cause audible effects, different DACs would behave very differently with regards to those effects. Thus I find that stating something like "cable X is better than Y" without qualifying the specific conditions, or even worse, descriptions of the "cable X has a softer aftertaste, with a hint of plum" type at least as misdirected as the simplistic "USB cables have no audible effects" statement.

[Julf]

Many people think they are listening for jitter as a distinct item but jitter simply effects music frequencies and changes the sound.

 

Which is why a double-blind ABX is the best way to compare cables (along with measurements).

[prufrock]

No doubt some of the senior members are sitting back having a chuckle. Classic newbie mistake, i.e move in and think you are going to sort it out. Not going to happen old son - audio is different and there will always be people who say they can hear special things. Tell them they are hearing things and they will understandably take offence and talk even louder and more often. Best thing you can do is shutup and don't mention it.

 

Because it is a sensitive issue telling someone they are hearing things, a lot of non -confrontational type listeners will avoid getting into it. When you think about it, even if the testing of claims was more comprehensive, the problem would still be there.

All you can do is manage it. And shutup.

[Julf]

Best thing you can do is shutup and don't mention it.

 

At least it is the most sensible thing to do. But then again, I do like the Winston Churchill quote "You have enemies? Good. That means you've stood up for something, sometime in your life".

[The Computer Audiophile]

It would be far easier if people just went out to a dealer and asked that dealer to faclitate a blind test for them between a $5 USB cable and a high-end Audioquest or Wireworld cable. I do not see why any scrupulous, authorised dealer with a reputation to uphold would not oblige such a demonstration.

 

Most dealers I interface with would be happy to facilitate such a listening test not only in the dealer's showroom but in the listener's own system. I encourage people to find the right dealer and ask for such a demonstration / test. Ask and you shall receive.

 

I only wish there were more dealers to facilitate what the users' want but many people live quite a distance from even a BestBuy location.

[4est]

At least it is the most sensible thing to do. But then again, I do like the Winston Churchill quote "You have enemies? Good. That means you've stood up for something, sometime in your life".

 

And this is precisely why I am willing to get into the fray about such things. I do not care if a particular person agrees or disagrees with my experiences. I most often get involved as the nay sayer in suggesting that everyone keep experimenting. Simply stated, no one "knows", and quite often the ones who think they do are the most misguided.

 

I have a quote on my refrigerator:"To know that we do not know is the beginning of wisdom.".

 

Julf: Nice to see that you changed your signature, and yes, I do pay attention...

[prufrock]

At least it is the most sensible thing to do. But then again, I do like the Winston Churchill quote "You have enemies? Good. That means you've stood up for something, sometime in your life".

 

With those words in mind, and a strengthened resolve, one presses on then.

[Julf]

Simply stated, no one "knows", and quite often the ones who think they do are the most misguided.

 

Well, speaking for some of us "EE types", we might not "know" in the absolute sense, but there is enough scientific knowledge and engineering understanding in the world to allow us to build bridges that don't break, make machines that fly through the air - and make equipment that allows us to capture the work of musicians, and transfer it in a reasonably true form to your living room. Unfortunately that same technology allows some people to make "music" without ever touching a real instrument and without ever disturbing any air with any sound waves.

 

My issue is that it is often (but not always) the people with the least understanding of science and engineering that are most opposed to applying scientific principles to understanding what makes our systems sound the way they do.

 

Julf: Nice to see that you changed your signature, and yes, I do pay attention...

 

Appreciated - I was sure I was on everybody's ignore list by now

[4est]

Well, speaking for some of us "EE types", we might not "know" in the absolute sense, but there is enough scientific knowledge and engineering understanding in the world to allow us to build bridges that don't break, make machines that fly through the air - and make equipment that allows us to capture the work of musicians, and transfer it in a reasonably true form to your living room. Unfortunately that same technology allows some people to make "music" without ever touching a real instrument and without ever disturbing any air with any sound waves.

 

My issue is that it is often (but not always) the people with the least understanding of science and engineering that are most opposed to applying scientific principles to understanding what makes our systems sound the way they do.

 

I do not ignore anything. Even if I completely disagree with a poster's position, I will listen with intent. I am here to learn and to share, and there may just be a nugget of truth or a viable paradigm to be had. There are EE types here that claim to hear, but do not know. I find it interesting that you claim to not hear, but to understand enough to not wonder why not. You may find this difficult to believe, but I do have some engineering background. Enough to know that much of this seems like hogwash until you have repeatably witnessed it over the last 30 years on my and others systems.

 

The (your) continued recital about people refusing to apply scientific engineering principles simply does not apply to very many posters on this forum. I watched the birth of audiophile cables, the resurgence of tubes and phono, and now the birth of computer based transports and audiophile USB cables. In this, change has been the only constant. Well, that and people fighting about it.

[Julf]

I do not ignore anything.

 

Neither do I - in terms of having anyone on an ignore list. There is a lot of silliness I ignore with respect to my MD's concern for my blood pressure.

 

I find it interesting that you claim to not hear, but to understand enough to not wonder why not.

 

What makes you think I don't wonder about that? But I still wonder much less about that than I admire the ability of my brain to deceive me. Which is why I don trust my ears anyway - there is too much brain filtering going on. It is unbelievably enlightening to compare double blind test results with plain blind tests and non-blind tests. Or at least enlightening to me.

 

The (your) continued recital about people refusing to apply scientific engineering principles simply does not apply to very many posters on this forum.

 

I agree - it only applies to some very vocal ones.

 

I watched the birth of audiophile cables, the resurgence of tubes and phono, and now the birth of computer based transports and audiophile USB cables. In this, change has been the only constant. Well, that and people fighting about it.

 

I have watched the same things, and I have to disagree - it is funny how little has actually changed in terms of the attitudes, prejudices and perceptions of people, despite the fact that technology has changed enormously.

[chg]

I am not suggesting the effect is the same or that is is indeed the effect itself. I am trying to find a more accessible illustration as to how noise well below the audible noise floor in digital audio alters the sound we hear and how the distribution of that noise (i.e spectral analysis) changes the sound as that noise spectrum changes. The relationship I am trying to draw here is that jitter has different characteristics with different equipment combinations because the noise spectrum is different with different equipment and different cables. And in the case of dithering from 24 bits to 16 bits, noise is also added and the spectrum altered (by noise shaping).

 

In the absense of the ability to do real ABX testing in a system with different USB cables, experimenting with noise shaping 24 bit audio is neverthless (in my opinion) a viable and accessible method by which to get an understanding of the notion that noise well below audible thresholds - whether that be induced by software or induced by a USB cable - can and does change what we hear.

 

If one can be accepting that a 16 bit version of a file sounds different than a 24 bit version of the exact same file even when listening at an average level of 60dBA, in my view it then becomes a much smaller leap of faith to accept that if a cable changes the spectrum of jitter (which is often at similar levels to noise artifacts caused by reducing world length) then it too can arguably change the sound. That is all I am trying to point out here.

 

It would be far easier if people just went out to a dealer and asked that dealer to faclitate a blind test for them between a $5 USB cable and a high-end Audioquest or Wireworld cable. I do not see why any scrupulous, authorised dealer with a reputation to uphold would not oblige such a demonstration. It's not going to help their business to sell a $500 USB cable to someone who can't hear the difference between it and a Hewlett Packard printer cable (because in general terms people who feel they are ripped off are usually unhappy about it), yet dealers are obviously selling dedicated audio USB cables on a routine basis, even though for the most part, these dealers have approval schemes and return policies (even online dealers such as The Cable Company). Even if 99 people out of 100 cannot hear the slightest difference between those cables (and I have absolutely no idea what that figure might really be), it only takes 1 person to correctly state which cable is which say, 10 times out of 10, to illustrate that the cables do indeed sound different. In my view a lot of the USB / digital cable debate hinges around this concept. In stating as a fact that USB cables make no difference, it does not take into account that somewhere in the world, and perhaps in audio dealer showrooms on a daily basis - someone may actually have truly blind tested them in a robust test and picked which was which each and every time.

 

I do concede that USB cables may not produce audibly different results in some cases, but I for one cannot and will not ever state that as a fact, since I have not heard every DAC or every USB cable, let alone blind tested all the possible combinations. And even if I had, just because I might not hear a difference myself does not mean someone else with better hearing and more advanced listening skills might hear a difference. It would only take one person in the world to successfully ABX two different USB cables using "the most perfect DAC ever built" to prove this latter concept wrong as well (even if for example, 10,000 other people can't hear the slghtest difference). Afterall, the debate with regard to digital cables and USB cables in particular seems to be more along the lines that they simply cannot and do not make any difference at all, rather than what I consider the more plausible scenerio - that being they do make differences, it is just that a significant subsection of the human population either do not possess the listening skills and / or equipment to hear those differences or have already made their mind up without feeling the need to actually thoroughly investigate it for themselves by way of extended auditions carried out with an open mind.

 

This is the most well written cable perspective I've ever read. Excellent job JonP.

 

And, beginning with post 253 to 266: the most productive, sensible, cable discussion I've ever witnessed.

[Paul R]

The (your) continued recital about people refusing to apply scientific engineering principles simply does not apply to very many posters on this forum.[/Quote]

 

I agree - it only applies to some very vocal ones.[/Quote]

 

I suppose you mean those who find your persistent arguments not compelling. Have you considered that nobody is really interested in your smart-alec comments about what USB Cable they are using? We understand you use a printer cable you got with a $29 Canon printer. Good luck with that. We get that is your opinion and you enjoy making fun of or being nasty to everyone else.

 

It is really getting old. People around here avoid topics you try to dominate. Nobody appreciates your constant sniping just because you don't want to spend $100 on a USB cable. Other people have systems that a $100 cable makes a difference in. *I* do in fact.

 

Please go leave your sarcastic droppings in your own sandbox, and let people who are interested in USB cables just discuss the subject without your constant harassment. Nobody needs you to save them from themselves.

 

-Paul

[TJHUB]

Fun discussion...

 

I recently received a Pangea USB-PC cable. It has really improved things nicely to my very pleasant surprise. For such an inexpensive USB cable, I think it's pretty incredible.

 

The Pangea replaced a fancy USB printer cable I had for about 9 years now. No surprise, right? Well, not really. I tried a few USB cables about a year ago when I was running an Alix (Linux PC) with an Audiophilleo 2. I was disappointed to find out how different USB cables sounded. The USB cable that came with the Audiophilleo sounded terrible. I also tried a couple Wireworld cables, one that I remember was a pricey Silver Starlight. It was far too thin and strident sounding. None of the cables I tired sounded nearly as balance and clear as my trusty old printer cable.

 

I recently got back into USB when I build my CAPS v2 server. I was running the printer cable, and liking the sound very much. But I was not happy running an old printer cable on my shiny new music server. I decided to try the Pangea before looking into more expensive USB cables.

 

The Pangea gives more clarity and extension in the treble, but it does this without any perceivable shift in tone or timbre. The clarity is very impressive overall. The bass the most notable change. It is very defined, and has fantastic impact and presence.

 

Is the Pangea perfect? Likely not. Is it an exceptional value at under $28.00 shipped for a 0.5 meter USB cable? In my setup, YES!

[mav52]

Hi Mav - Do you know what the audible effects of jitter are? What to listen for? What frequencies are most effected by jitter?

 

Many people think they are listening for jitter as a distinct item but jitter simply effects music frequencies and changes the sound.

 

timing variations in the clocks whereby the accuracy error that affects each clock edge and cycle is digital clock jitter. Sampling jitter, transmitter jitter, line induced jitter and interfering-noise induced jitter are a few more. To date, I've never heard bad jitter and why should we if we are using equipment that has been engineered to reduce jitter. So Chris, how about providing some test measurements or samples of bad jitter so we can hear it.

[Paul R]

So Chris, how about providing some test measurements or samples of bad jitter so we can hear it.

 

I am not Chris, but if you want a gross example, which is very good for learning what to listen for, pick up this DVD player on Amazon, play a CD through the digital out, or if you have the equipment, measure the digital out with a test signal on CD. That nastiness you hear? It is caused by the jitter this beastie generates.

 

You hear jitter of some type in all digital music- if nothing else but the jitter irrevocably embedded by the a/d conversion step. Some types of jitter can also play havoc during a/d conversion because of the effect on the filters. Again, it is easy to hear that if you know what your listening for. Might have to be guided to hear it the first time or two though.

 

Paul

[mav52]

I am not Chris, but if you want a gross example, which is very good for learning what to listen for, pick up this DVD player on Amazon, play a CD through the digital out, or if you have the equipment, measure the digital out with a test signal on CD. That nastiness you hear? It is caused by the jitter this beastie generates.

 

You hear jitter of some type in all digital music- if nothing else but the jitter irrevocably embedded by the a/d conversion step. Some types of jitter can also play havoc during a/d conversion because of the effect on the filters. Again, it is easy to hear that if you know what your listening for. Might have to be guided to hear it the first time or two though.

 

Paul

 

 

A DVD, good god man I thought we were talking computer audio, how about an example of a DAC that you can actually hear the 'jitter'. It's either a poorly engineering DAC or poor recording. I still say, if you can't hear it why care, it's a non issue. Save you money.

[Julf]

Please go leave your sarcastic droppings in your own sandbox, and let people who are interested in USB cables just discuss the subject without your constant harassment. Nobody needs you to save them from themselves.

 

Ah, I guess it was one of the evenings when Dr. Raulerson stayed home, while Mr. Paul Hyde got out to play.

[4est]

Ah, I guess it was one of the evenings when Dr. Raulerson stayed home, while Mr. Paul Hyde got out to play.

 

And this is coming from the man whom complains about ad hominems constantly!

 

I tend to agree with Paul on this. If others want to go "round and round" wasting their time and money on something another(you) believes is bullocks. Then let them and leave your snarky comments to yourself. We are not talking about food, shelter and kids here, but expendable income used for an expensive hobby. In the scope of things, $100 for a cable is pittance as compared to the other expenditures.

[GrahamJohnMiles]

I don't use a cable, just a short usb adapter connecting laptop to spdif box.