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USB cable and Sound Quality - Page 29  

post #421 of 783
Quote:
Originally Posted by billybob_jcv View Post

What does this mean?
From usb_20.pdf found here: http://www.usb.org/developers/docs/usb_20_071012.zip
Page 142:
"Use of ferrite beads on the D+ or D- lines of full-speed devices is discouraged."
Page 143:
"The use of ferrites on high-speed data lines is strongly discouraged."
I was always under the impression that ferrite beads were used on substandard cables, but that on cables that are fully compliant with the USB 2.0 spec, they are not needed (and perhaps discouraged?)
I was also under the impression that a ferrite bead is a choke - a passive low-pass filter. They are used to eliminate EMI/RF noise. I was also under the impression this noise is well beyond the audio frequency range. How that would affect the audio encoded in a digital signal without also affecting the digital signal itself is beyond me.

 

Mikeaj beat me to it biggrin.gif, but here are my 2 cents:

 

That is a good point. Here is a post I found interesting about it:

http://www.head-fi.org/t/353613/high-quality-usb-cable-for-usb-dac/75#post_4753989

 

Ferrite beads effect on signal integrity probably depends on the cable length and gauge. Also, USB digital signals are well above the audio frequency range (partly depending on sampling rate and bit-width,) and may be affected by EMI/RF, and ferrite beads. That said, I don't see how this would be a big deal if the USB cables are standards compliant, unless the conditions are extremely noisy.


Edited by ultrabike - 9/16/12 at 1:01am

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post #422 of 783
Quote:
Originally Posted by liamstrain View Post

Line noise in a USB cable would be irrelevant at the D/A conversion point unless it was so problematic as to actually affect the voltage swing enough to switch bits (extremely unlikely). 

 

Any noise you hear after the D/A conversion would more likely be coming from somewhere else in the chain and should be unaffected by the USB cable. I could see maybe some case if the amplification circuit is powered via the USB... a ferrite choke cost about $2, and would be any easy thing to add to any USB cable to test if you continue to think that the culprit lies there.

 

You state you heard differences between them. Did you do any sort of controlled/blind testing or ABX to determine this, or is this based on your own cable switching and general impressions. 

 

This post should have ended the thread. USB cables do not effect sound quality. This is a fact. If you think they do, you are wrong.

post #423 of 783
Exactly, everything which has not yet been proven is wrong, and what is supported by current research is the only possibly truth, regardless of scope.  Only dualisms can exist.  The current understanding of the world I have is valid, and anything which is outside or opposed to this is completely invalid.  Kudos.

Edited by drez - 9/19/12 at 12:18am
post #424 of 783
Quote:
Originally Posted by drez View Post
Exactly, everything which has not yet been proven is wrong, and what is supported by current research is the only possibly truth, regardless of scope.  Only binary dualisms can exist.  The current understanding of the world I have is valid, and anything which is outside or opposed to this is completely invalid.  Kudos.

 

Any claim that contradicts basic theoretical knowledge, and hasn't been shown experimentally, is wrong.

I am tired of being nice to these claims, saying things like "maybe there is a way.. I don't how, but maybe... who knows?", if that is what you are implying I do. If there are any objective truths in the world, USB cables not affecting sound quality is one of them.

 

 

Also, a binary dualism would have 4 possible outcomes...


Edited by Eisenhower - 9/18/12 at 10:30am
post #425 of 783
Quote:
Originally Posted by Eisenhower View Post

 

Any claim that contradicts basic theoretical knowledge, and hasn't been shown experimentally, is wrong.

I am tired of being nice to these claims, saying things like "maybe there is a way.. I don't how, but maybe... who knows?", if that is what you are implying I do. If there are any objective truths in the world, USB cables not affecting sound quality is one of them.

 

 

Also, a binary dualism would have 4 possible outcomes...

 

SO I guess you have an expert knowledge of USB audio and have conducted blind tests on USB cables as used in DAC's and SPDIF interfaces?  I guess you have had experience comparing USB cables in a stereo setup which is transparent enough for audio production?  Or have you just been reading some sound science articles and lurking in HydrogenAudio a little?

 

I think it is quite clear what I mean by binary dualism, as in binary thinking which relies on a dualistic view of a topic at hand.  IE USB cables either affect audio or they don't.  Either something is in agreement with accepted standards of testing and a greater body of theory or it is wrong.  Seems binary to me.

 

I don't care for you to tenderly word your opposition to the claim that USB cables can affect audio, or that your understanding of electronics and audio technology is in disagreement with the idea that USB cables can make a difference to audio.  I clearly understand why USB cables should not affect sound quality, I have done plenty of reading in this area and have spend a lot of time researching USB and computer audio.  I also understand the limits of my understanding in these areas and of the research I have conducted so far, as well as the limits of my hearing and of the reliability of testing without proper controls.

 

But anyway thank you for your valuable insight it has contributed greatly to this thread.  SO kind of you to tell me that I am wrong.  I had never even considered it before.


Edited by drez - 9/19/12 at 12:19am
post #426 of 783
Quote:
Originally Posted by Eisenhower View Post

 

This post should have ended the thread. USB cables do not effect sound quality. This is a fact. If you think they do, you are wrong.


This thread belongs in the voodoo-section "http://www.head-fi.org/f/21/cables-power-tweaks-speakers-accessories-dbt-free-forum"

USB-cables do not transfer audio, they transfer zeros and ones .  There IS no audio until the DAC has done it's job .

post #427 of 783
Quote:
Originally Posted by AKG240mkII View Post


This thread belongs in the voodoo-section "http://www.head-fi.org/f/21/cables-power-tweaks-speakers-accessories-dbt-free-forum"

USB-cables do not transfer audio, they transfer zeros and ones .  There IS no audio until the DAC has done it's job .

 

blink.gif The USB cable carries PCM data transferred via the USB bus - it carries audio information just you can't wire your headphones directly into the USB port.

 

If this thread was moved to the cables subforum there might be a few less useless posts to contend with, but some people on the science forum actually have good insight into the technology, have conducted DBT's etc (not me personally.)  Others just seem more interested in trying to stir audiophiles.  There is a place for that and it is called HydrogenAudio.


Edited by drez - 9/19/12 at 1:49am
post #428 of 783
Ike is basically right. On the continuum of things a hifi nut needs to pay attention to, usb cables are down there with the color of carpet and whether you're going to let the dog sit on the leather sofa or not.
post #429 of 783
Quote:
Originally Posted by bigshot View Post

Ike is basically right. On the continuum of things a hifi nut needs to pay attention to, usb cables are down there with the color of carpet and whether you're going to let the dog sit on the leather sofa or not.

 

In the grander scheme of things you are probably right - if something cant be detected in DBT it's probably not that important...

post #430 of 783
Quote:
Originally Posted by drez View Post

 

SO I guess you have an expert knowledge of USB audio and have conducted blind tests on USB cables as used in DAC's and SPDIF interfaces?  I guess you have had experience comparing USB cables in a stereo setup which is transparent enough for audio production?  Or have you just been reading some sound science articles and lurking in HydrogenAudio a little?

 

I think it is quite clear what I mean by binary dualism, as in binary thinking which relies on a dualistic view of a topic at hand.  IE USB cables either affect audio or they don't.  Either something is in agreement with accepted standards of testing and a greater body of theory or it is wrong.  Seems binary to me.

 

I don't care for you to tenderly word your opposition to the claim that USB cables can affect audio, or that your understanding of electronics and audio technology is in disagreement with the idea that USB cables can make a difference to audio.  I clearly understand why USB cables should not affect sound quality, I have done plenty of reading in this area and have spend a lot of time researching USB and computer audio.  I also understand the limits of my understanding in these areas and of the research I have conducted so far, as well as the limits of my hearing and of the reliability of testing without proper controls.

 

But anyway thank you for your valuable insight it has contributed greatly to this thread.  SO kind of you to tell me that I am wrong.  I had never even considered it before.

 

I took a DSP class at my university, not that it matters, since you ought to judge an argument on technical merit and not on the background of the person that makes it. Doing so is what is referred as an ad hominem fallacy. Saying "binary dualism" is what is known as tautology, because you are saying the same thing twice. Seeing as you believe USB cables might change sound quality, I am not surprised you are using "binary" incorrectly...

 

One of the reasons digital signals are used for telephones, TV, etc. is because they are not affected by the cable. It is a 1 or a 0. A digital signal is either transmitted or it isn't. Either a usb cable is functioning, or it isn't (one might call those binaries, or maybe dualisms, but certainly not binary dualisms). A $400 silver USB cable isn't going to improve the quality of the transmitted 1's and 0's, creating a subtle expansion of the soundstage. If it did, then there is something seriously wrong with your DAC. But anyone spending $400 on a USB cable will probably be using a functioning DAC.

 

As for jitter (since USB audio is not time corrected) even a moderately long USB cable will not affect jitter in an audible way. That is why there haven't been any blind listening tests showing that USB cables affect sound quality. Do people keep their sources that far away from their DAC that it would affect sound quality? NO.

 

Making claims that are based on fantasy are no more a valuable insight than dismissing them - claims made without evidence can be dismissed without evidence.

In order to make progress in hi-fi audio, you have to accept that certain claims are in fact wrong.


Edited by Eisenhower - 9/19/12 at 12:01pm
post #431 of 783
Quote:
Originally Posted by purrin View Post

Because any dielectric will polarize the electrons. Essentially the cable becomes a capacitor.

 

The EMI theory however is more sound. I actually got a subtle, but notable improvement by wrapping my USB cable with aluminum foil.

 

700

Sorry, I couldn't help but make the joke even though I can see the foil helping. I could help it and I've done the same for various RF issues in the past. I could see it helping if there was spurious dig noise which would be expected in modern computer based systems.

post #432 of 783
Quote:
Originally Posted by Eisenhower View Post

 

I took a DSP class at my university, not that it matters, since you ought to judge an argument on technical merit and not on the background of the person that makes it. Doing so is what is referred as an ad hominem fallacy. Saying "binary dualism" is what is known as tautology, because you are saying the same thing twice. Seeing as you believe USB cables might change sound quality, I am not surprised you are using "binary" incorrectly...

 

One of the reasons digital signals are used for telephones, TV, etc. is because they are not affected by the cable. It is a 1 or a 0. A digital signal is either transmitted or it isn't. Either a usb cable is functioning, or it isn't (one might call those binaries, or maybe dualisms, but certainly not binary dualisms). A $400 silver USB cable isn't going to improve the quality of the transmitted 1's and 0's, creating a subtle expansion of the soundstage. If it did, then there is something seriously wrong with your DAC. But anyone spending $400 on a USB cable will probably be using a functioning DAC.

 

As for jitter (since USB audio is not time corrected) even a moderately long USB cable will not affect jitter in an audible way. That is why there haven't been any blind listening tests showing that USB cables affect sound quality. Do people keep their sources that far away from their DAC that it would affect sound quality? NO.

 

Making claims that are based on fantasy are no more a valuable insight than dismissing them - claims made without evidence can be dismissed without evidence.

In order to make progress in hi-fi audio, you have to accept that certain claims are in fact wrong.

 

I'm sorry I didn't realise that you raised an argument, in fact I would classify your first post as a comment, and with the basic message intended to tell people who do not agree with your viewpoint that they are wrong.  Criticising tautologies is just a way of playing grammar nazi.  You understood perfectly what I was saying but chose to focus criticism on an insignificant error of syntax. If the intention were different I would appreciate the correction.  I am here to learn.

 

I'm guessing you have captured the digital signal coming out of this $400 silver USB cable so you can say for sure that there has been no influence over the jitter of the signal?  Can you tell us what magnitude and type/s of jitter this $400 USB cable you speak of has introduced against a reference USB cable?

 

You are correct that USB audio is not time corrected, and most asynchronous devices have a  buffer on the receiver side.  Previously we have discussed that USB cannot transfer the audio bit by bit as the frequency of the bus is not high enough, therefore it must be using some kind f bulk transfer.  This is fair enough and I understand that this means that timing variances from the computer should not affect the signal at the other side of the USB device an a meaningful way, at least based on my limited understanding - I am not an expert in the field.

 

Some people for whatever reason do use quite long USB cables, personally I do not as my gear is not spaced that far.

 

Making claims based on fantasy is not what I am here to do, but if you notice other posters who have been on this forum a little longer tend to ask for further evidence or point to where any specifici fantasy is flawed rather than telling people they are wrong which lets face it will not influence anyone and will not contribute toward the general wellbeing of the thread, and is most likely an attempt to stir up people rather than contribute toward the thread.

 

I have a different philosophy, which is in order to make progress in hifi I chose to trust my ears, whether testing an a mplifier or testing a headphone, or even a cable.  I do not offer this as "evidence" to anyone, it is my opinion based on my experience and I encourage others to share their experience or opinion even if it contrary to my own.

 

It seems this thread has descended into an opprtunity to stirr up audiophiles, so I htink it might be best to bring a mod in to get the thread back on track.


Edited by drez - 9/19/12 at 9:53pm
post #433 of 783
We've gone over this stuff over and over again, and the pattern is the same every time. First someone makes a statement about an effect that can't be measured or proven. Then the regulars answer it with facts and suggestions for how to objectively verify the effect. Then the person who made the unsupportable claim comes back saying science doesn't know everything. Then the regulars say "prove it exists". Then the person making the claims gets mad. Pretty soon the mods are called in and the thread is locked.

We aren't mad. We don't need to be protected by the mods. We are never the ones who cry to the mods to lock threads. We're just talking about observable phenomenon.

Just saying the effect doesn't exist is cutting to the chase in the hopes that it won't go down the road of anger and hard feelngs. If you are willing to discuss what you are theorizing, and subject it to objective tests without getting mad, we're happy to play. But it never goes that way. It always goes down the road of anger.
Edited by bigshot - 9/19/12 at 10:53pm
post #434 of 783
Quote:
Originally Posted by bigshot View Post

We've gone over this stuff over and over again, and the pattern is the same every time. First someone makes a statement about an effect that can't be measured or proven. Then the regulars answer it with facts and suggestions for how to objectively verify the effect. Then the person who made the unsupportable claim comes back saying science doesn't know everything. Then the regulars say "prove it exists". Then the person making the claims gets mad. Pretty soon the mods are called in and the thread is locked.
We aren't mad. We don't need to be protected by the mods. We are never the ones who cry to the mods to lock threads. We're just talking about observable phenomenon.
Just saying the effect doesn't exist is cutting to the chase in the hopes that it won't go down the road of anger and hard feelngs. If you are willing to discuss what you are theorizing, and subject it to objective tests without getting mad, we're happy to play. But it never goes that way. It always goes down the road of anger.

 

I don't think this is an accurate representation of the dialogue between myself and Eisenhower, my beef is not with challenges to any particular theory someone may have but to general and inflammatory attempts to make universal declarations that something is right or wrong, chest beating, or attempt to put someone down rather than addressing a specific argument or idea.

 

The method in which an argument or opinion is delivered is what decides whether or not anyone will get angry.  Playing grammar nazi is again not what I would consider to be a mature and respectful way to make an argument (again I am referring to the dialog between Eisenhower and myself.)

post #435 of 783
Quote:
Originally Posted by drez View Post

 

I'm sorry I didn't realise that you raised an argument, in fact I would classify your first post as a comment, and with the basic message intended to tell people who do not agree with your viewpoint that they are wrong.  Criticising tautologies is just a way of playing grammar nazi.  You understood perfectly what I was saying but chose to focus criticism on an insignificant error of syntax. If the intention were different I would appreciate the correction.  I am here to learn.

 

I'm guessing you have captured the digital signal coming out of this $400 silver USB cable so you can say for sure that there has been no influence over the jitter of the signal?  Can you tell us what magnitude and type/s of jitter this $400 USB cable you speak of has introduced against a reference USB cable?

 

You are correct that USB audio is not time corrected, and most asynchronous devices have a  buffer on the receiver side.  Previously we have discussed that USB cannot transfer the audio bit by bit as the frequency of the bus is not high enough, therefore it must be using some kind f bulk transfer.  This is fair enough and I understand that this means that timing variances from the computer should not affect the signal at the other side of the USB device an a meaningful way, at least based on my limited understanding - I am not an expert in the field.

 

 

I reposted liamstrain's point. Why would I make an argument when someone's already made it for me? Having a correct understanding of digital audio is not a viewpoint. We aren't discussing politics, we are discussing fact based science.

 

So let me get this straight, you questioned my credentials, when you yourself have none? That is hypocritical.

It also isn't fair to demand that I must disprove your wildly nonsensical claim that USB cables affect sound quality. You are making the extraordinary claim, so you provide the evidence. This is how it works.

 

I am not a grammar nazi, unless someone tries to sound intellectual with fancy sounding ostentatious concepts like "binary dualism" that actually don't make any sense. I also don't like it when people use sarcasm instead of making their point directly, which is what you did in your first response.

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