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Is it possible to improve the USB as a cable for audio purposes? - Page 6

post #76 of 93

I'm going to be brief and just add that in the USB specification the logic levels is actually achieved by a pair of wires - D+ and D-.

A logical one is when BOTH D+ is over 2.8V and D- is under 0.3V.

A logical zero is when BOTH D+ is under 0.3V and D- is over 2.8V.

 

That huge 2.5V difference as well as a the paired representation means the chance of "corruption" from material difference is basically zero. 

post #77 of 93
Quote:
Originally Posted by nanaholic View Post

I'm going to be brief and just add that in the USB specification the logic levels is actually achieved by a pair of wires - D+ and D-.

A logical one is when BOTH D+ is over 2.8V and D- is under 0.3V.

A logical zero is when BOTH D+ is under 0.3V and D- is over 2.8V.

 

That huge 2.5V difference as well as a the paired representation means the chance of "corruption" from material difference is basically zero. 


I already told him that. His argument was that because D+ and D- are wrapped along the Vcc and Ground, they're interacting with each other.

There's no arguing with someone who has a lack of knowledge.

post #78 of 93
Quote:
Originally Posted by Caution View Post

 

All those cables you listed have a similar generic construction, which I agree with you and think they sound the same. The cables that sound noticeably different are the ones where the power and data lines are separated (This is why I said cables in differing price ranges as these are usually more expensive). No, it's not my eyes that deceive me, I don't think they sound different because they look better. My "best looking" after market cable actually induces simbilance and physically hurts to listen to, I do not get this with any other cable. Note: I have never mentioned anything about "improvements" in this thread, only differences.

 

Whatever distance there is between the power and data lines throughout the length of the cable, you still have a set of standard USB connectors which have the power lines and data lines close to eachother, so I fail to see the advantage of this cabling strategy.

 

Also, AFAIK while USB 2.0 in isochronous mode does not offer re-transmission and error correction, it does offer error detection, and massive errors more than likely result in frames being dropped. Even if these packets were not dropped, random errors in the bit stream would result in random N-bit sample values. I have no idea how this could ever result in sibilance or how your explanation of the analog and well understood nature of digital communications (in particular BPSK) explains every sound coloration under the sun.

 

I try to keep an open mind about it, and if you have a reasonable explanation I'm all for hearing it though...

post #79 of 93

Fair enough, perhaps my explanation was lacking. How about I send one of you one of my USB cables for you guys to decide? Send me a PM if you are interested.

post #80 of 93
Quote:
Originally Posted by Caution View Post

Fair enough, perhaps my explanation was lacking. How about I send one of you one of my USB cables for you guys to decide? Send me a PM if you are interested.

Cannot speak for others, but I wouldn't have you spend money on my account. Your headphone audio inventory shows that you are serious about your audio and I respect that.

 

So far I personally have not found improvement (or degradation) in audio by using the USB cables that I have used. I also have not seen solid evidence that shows that I should either, if such cables strive for standard compliant signal integrity.

 

I do try to attend meets (whenever family life allows), and if possible will make every attempt to see if I can hear any differences, if high end USB cables are available to sample... Don't get your hopes up though biggrin.gif

post #81 of 93
Quote:
Originally Posted by Caution View Post

 

Yes I completely agree with double blind testing, and will do this in the future.

 

However a couple of points as mentioned in my previous post, one of my cables is actually pretty painful to listen to (physically), I'm not sure if auto suggestion can be huge enough to account for this... This had nothing to do with volume matching as the cable was used in an a/b test, and also kept in my system for a couple of days.

 

Well first of all it would be great if double blind listening tests could be organised and it is good that you see this as a valuable exercise.

 

You write that one your your cables is painful to listen to. Certainly the fact of sound being painful to listen to is hugely within the scope of the flexible way we perceive sound. Emotional response to sounds is extremely flexible indeed. In the condition of misophonia, for example, people can become so upset by certain sounds that they will go to huge lengths to avoid them. Misophonia is a very common condition.

 

I suspect that if you were to perform double blind listening tests then the USB cables that you think sound so very different would be indistinguishable in those tests, but of course I don't know that and so I would love for those tests to take place.

 

Suggestion and autosuggestion are extremely powerful and influence everyone so I am certain that there are things which I believe cause a detectable difference in my sound system which in fact I would not be able to distinguish in a double blind test.

post #82 of 93
Quote:
Originally Posted by Caution View Post

Fair enough, perhaps my explanation was lacking. How about I send one of you one of my USB cables for you guys to decide?

 

I think a far more effective way would be to conduct one yourself. But do follow the process of a DBT. 

 

To give you some idea of the ability of our brain to create false effects, take a look at this: http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html

And its the same thing with auditory illusions: http://www.newscientist.com/article/dn13355-music-special-five-great-auditory-illusions.html

 

I'm just trying to suggest there are other things at play, other than the audio equipment itself. A lot of the times our senses are interpreted differently depending on our mood, the prior information we have etc.

 

Personally I always tend to localize sounds more towards a light source, for example a table lamp (if other lights in the room are off). But the moment I switch it off (make the room completely dark), the localization improves.


Edited by proton007 - 2/1/13 at 1:00am
post #83 of 93
Quote:
Originally Posted by ultrabike View Post

Cannot speak for others, but I wouldn't have you spend money on my account. Your headphone audio inventory shows that you are serious about your audio and I respect that.

 

So far I personally have not found improvement (or degradation) in audio by using the USB cables that I have used. I also have not seen solid evidence that shows that I should either, if such cables strive for standard compliant signal integrity.

 

I do try to attend meets (whenever family life allows), and if possible will make every attempt to see if I can hear any differences, if high end USB cables are available to sample... Don't get your hopes up though biggrin.gif

 

Sending the cable over shouldn't be too much, and I'm more than willing to donate for science confused_face(1).gif and the community . I'd be very interested to see what the skeptics say having been one my self.

 

It's very interesting with these cables, some are immediately noticeable (ouch the pain) and some have subtle yet noticeable differences. I wouldn't have believed it my self If I hadn't tried, that's what makes this hobby fun in my opinion.  If you've tried something marketed as an "audiophile" usb cable and couldn't tell a difference, I'd have no problems and would respect your opinion. But as you can see some people haven't tried them and won't bother trying them as such differences are apparently theoretically impossible.

 

 

 

Quote:
Originally Posted by p a t r i c k View Post

 

Well first of all it would be great if double blind listening tests could be organised and it is good that you see this as a valuable exercise.

 

You write that one your your cables is painful to listen to. Certainly the fact of sound being painful to listen to is hugely within the scope of the flexible way we perceive sound. Emotional response to sounds is extremely flexible indeed. In the condition of misophonia, for example, people can become so upset by certain sounds that they will go to huge lengths to avoid them. Misophonia is a very common condition.

 

I suspect that if you were to perform double blind listening tests then the USB cables that you think sound so very different would be indistinguishable in those tests, but of course I don't know that and so I would love for those tests to take place.

 

Suggestion and autosuggestion are extremely powerful and influence everyone so I am certain that there are things which I believe cause a detectable difference in my sound system which in fact I would not be able to distinguish in a double blind test.

 

 

Doing a double blind test would be an interesting thing to do in the office, I'll see If I can organize one with a colleague when it gets quiet.

post #84 of 93
Quote:
Originally Posted by Caution View Post

 

It's very interesting with these cables, some are immediately noticeable (ouch the pain) and some have subtle yet noticeable differences.

 

I've noticed that 'ouch' effect with the same song, and the same setup. No need to change cables or amps. Just depending on how fatigued I am. Its all in the head.

post #85 of 93
Quote:
Originally Posted by Caution View Post

Like I said, binary digits are used as a simplistic model to help explain digital to the mass, it's obviously worked very well ask your mom or dad or even grandma how digital works. Chances are they will say 10101011! Well It's not literally 1s and 0s. Remember doing science in high school being taught something in class, only to go to uni to find out everything you have been taught is an oversimplification and is far from the truth?

I never said anything about usb cables decoding digital audio, I'm not sure where you got that from. What I'm talking about is signal integrity.Square waves in reality are not always perfect like you see in a text book, It's in analog form and therefore susceptible to alteration just like any other analog wave form, your DAC (and the engineers who designed the DAC) on the other hand is pretty smart and is able to approximate and interpret less than ideal signals it receives.
Well, what travels through the cable is indeed an analog waveform (and not even perfectly square, because these don't exist in real world), but the USB interface of the DAC will figure out some stream of 0s and 1s from it because it's a stupid digital device and that's the only thing it can do with any input signal.

To introduce some "meaningful" (i.e. not "random junk") distortion, the cable would really need to understand how this signal is going to be decoded to numbers by DAC's USB interface and how this numbers are going to be interpreted by the actual DAC chip. And then do some nontrivial math with them.
post #86 of 93
Quote:
Originally Posted by proton007 View Post

 

I've noticed that 'ouch' effect with the same song, and the same setup. No need to change cables or amps. Just depending on how fatigued I am. Its all in the head.

 

 

This happens when I A/B the cables too. So I'm not sure if we can blame fatigue. Perhaps my mind is playing tricks, I guess a DBT is the only way to find out.

post #87 of 93
Quote:
Originally Posted by Caution View Post

 

This happens when I A/B the cables too. So I'm not sure if we can blame fatigue. Perhaps my mind is playing tricks, I guess a DBT is the only way to find out.

 

I think it might be tricks or just fatigue sometimes i find a song intolerable through no excuse since im not ill and i didnt pretentiously pick the song to be unhappy with it.

post #88 of 93
Quote:
Originally Posted by Caution View Post

 

Doing a double blind test would be an interesting thing to do in the office, I'll see If I can organize one with a colleague when it gets quiet.

 

Doing these double blind tests correctly requires some time and consideration.

 

You need to do the comparisons a fairly large number of times to remove the possibility of chance.

 

It is best to get someone else to set up the test entirely for you, then you simply participate.

 

Then get that person to report on the results of the test.

 

It is really not the kind of thing you can do "when the office gets quiet".

 

It may surprise you that people in discussions on the Internet sometimes say they have performed a double blind test when they have not.

 

I recommend reading about this double blind test performed by Jason Victor Serinus on mains power cords.

 

http://www.hometheaterhifi.com/volume_11_4/feature-article-blind-test-power-cords-12-2004.html

 

Here you will see how one is conducted.

post #89 of 93
Quote:
Originally Posted by p a t r i c k View Post

I recommend reading about this double blind test performed by Jason Victor Serinus on mains power cords.

 

http://www.hometheaterhifi.com/volume_11_4/feature-article-blind-test-power-cords-12-2004.html

 

Patrick.  I agree that this was a well executed test that I had found that previously on my own.  Just wondering if you have links to or info relating to any other well run tests that you might share?

post #90 of 93
Quote:
Originally Posted by Hi Rez View Post

Patrick.  I agree that this was a well executed test that I had found that previously on my own.  Just wondering if you have links to or info relating to any other well run tests that you might share?

 

I'm afraid that is the only test for which have a link at present. Ages ago there was a lengthy thread here which included links to other writeup of tests. It is very hard to find that thread because the search terms such as "double blind test" or "ABX" will bring up so many threads in Sound Science.

 

I think there has been a mere handful of double blind tests carried out.

 

For me it is worthy of comment that there have been so few such test on Hi Fi components over the last 30 years.

 

The people most to blame for this are those that claim to be reviewers and the publications that take money to "review" equipment. They have the resources and they get new equipment sent to them. However they never do blind tests (since the mid 80s) because, of course, the last thing they wish to do is upset manufacturers in the Hi Fi industry and reveal that their own reviewers cannot hear all the differences they claim to hear.

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