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Testing audiophile claims and myths - Page 131

post #1951 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

Guys, I personally believe in cables, but not unobtanium ones that costs 8000$. For me that is more than absurd. 

However, I do believe in differences cables could bring to your system, bad or good. I have recently found out that even USB cables make a difference. Yeah...you heard me...usb cables. Bash me all you want, I do not care. All that I know is that I found a really cheap USB cable that really goes well with my system.

The usb cable costs 70$ or something like that. I gave it to a friend of mine who tested it along the stock, audioquest coffee (that has is 6x pricier) and wireworld starlight red (twice the cost). He liked my cable the most , even over the 6x times pricier AudioQuest coffee. He also did blind tests with them and concluded the same.

 

Before testing it and finding this, I thought usb cables were bs, but now I am sure that they can bring differences. However, I personally do not believe in very expensive cables. 

Yeah, you're gonna have to post some blind testing evidence if you're making a claim like that in this subforum.

 

The only way a USB cable could make a difference is if it had some sort of DSP chip in it. But that's a silly place to use a DSP at, you could just do it for free software side.


Edited by chewy4 - 3/5/13 at 5:50am
post #1952 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

Guys, I personally believe in cables, but not unobtanium ones that costs 8000$. For me that is more than absurd. 

However, I do believe in differences cables could bring to your system, bad or good. I have recently found out that even USB cables make a difference. Yeah...you heard me...usb cables. Bash me all you want, I do not care.

Well, we do not care about your anecdotes. So why even post in this forum? It's like saying "I never believed in aliens but yesterday I was abducted by them".

 

 

Quote:
All that I know is that I found a really cheap USB cable that really goes well with my system.

The usb cable costs 70$ or something like that. [anecdote ...]

Are you kidding?

 

 

edit: links removed, two posts containing those links are enough


Edited by xnor - 3/5/13 at 6:00am
post #1953 of 4174
Quote:
Originally Posted by chewy4 View Post

Yeah, you're gonna have to post some blind testing evidence if you're making a claim like that in this subforum.

 

The only way a USB cable could make a difference is if it had some sort of DSP chip in it. But that's a silly place to use a DSP at, you could just do it for free software side.

Told you that my friend DarKu, already did some blind tests that concluded he liked the Chord and Wirereworld starlight better than the AudioQuest coffee and the stock. I will ask of him to share his results here. 

I for one am sure that they make a difference, even though as I told you, before actually hearing and testing one i thought it was bs. 

I think the timing is everything. If you would have RAM or a big buffer inside your DAC, usb cables wouldn't make any difference. You cannot have error checking on the USB audio connection if you don't have a buffer. If you don't have error checking, well...if some zeroes become 1 and the other way around, you loose from quality.

USB audio streaming != USB data transfer


Edited by dan.gheorghe - 3/5/13 at 6:22am
post #1954 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

Guys, I personally believe in cables, but not unobtanium ones that costs 8000$. For me that is more than absurd. 

However, I do believe in differences cables could bring to your system, bad or good. I have recently found out that even USB cables make a difference. Yeah...you heard me...usb cables. Bash me all you want, I do not care. All that I know is that I found a really cheap USB cable that really goes well with my system.

The usb cable costs 70$ or something like that. I gave it to a friend of mine who tested it along the stock, audioquest coffee (that has is 6x pricier) and wireworld starlight red (twice the cost). He liked my cable the most , even over the 6x times pricier AudioQuest coffee. He also did blind tests with them and concluded the same.

 

Before testing it and finding this, I thought usb cables were bs, but now I am sure that they can bring differences. However, I personally do not believe in very expensive cables. 

How did he blind test a USB cable?

post #1955 of 4174
Quote:
Originally Posted by xnor View Post

Well, we do not care about your anecdotes. So why even post in this forum? It's like saying "I never believed in aliens but yesterday I was abducted by them".

 

 

Are you kidding?

 

 

edit: links removed, two posts containing those links are enough

What you said has no logic at all. 

 

I don't get it why some of you people take it personal :)), really. I am just trying to tell you my honest impressions on this, that is all. 

 

 

 

Quote:
How did he blind test a USB cable?

Well... both him and his wife participated. When one of them was listening the other one changed the cables. The one listening wrote his impressions down on paper.


Edited by dan.gheorghe - 3/5/13 at 6:23am
post #1956 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

Told you that my friend DarKu, already did some blind tests that concluded he liked the Chord and Wirereworld starlight better than the AudioQuest coffee and the stock. I will ask of him to share his results here. 

I for one am sure that they make a difference, even though as I told you, before actually hearing and testing one i thought it was bs. 

I think the timing is everything. If you would have RAM or a big buffer inside your DAC, usb cables wouldn't make any difference. You cannot have error checking on the USB audio connection if you don't have a buffer. If you don't have error checking, well...if some zeroes become 1 and the other way around, you loose from quality.

USB audio streaming != USB data transfer

Well I'd be very interested in what those cable makers are doing if he did manage to have a well controlled test.

 

Ever use a digital antenna? Those easily display the differences between a faulty digital signal and a perfect one and show how there is no in between. Timing is just as important for them.

post #1957 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

What you said has no logic at all. 

 

I don't get it why some of you people take it personal :)), really. I am just trying to tell you my honest impressions on this, that is all.

What I said has no logic, why?

 

What you posted makes little to no sense. Because:

- What you posted before are just anecdotes - if you don't know what that means read the definition of anecdotal evidence in a scientific context (also see my signature).

- You mentioned you found a really cheap USB cable, in the next sentence you say it costs $ 70.

- I do not take nonsensical claims personal and I'm not attacking persons, just nonsensical claims.

- If we want honest (not always the case) impressions that are not necessarily truthful we can go to the cables forum...

 

and:

Quote:
Originally Posted by dan.gheorghe View Post

Told you that my friend DarKu, already did some blind tests that concluded he liked the Chord and Wirereworld starlight better than the AudioQuest coffee and the stock. I will ask of him to share his results here. 

I for one am sure that they make a difference, even though as I told you, before actually hearing and testing one i thought it was bs. 

I think the timing is everything. If you would have RAM or a big buffer inside your DAC, usb cables wouldn't make any difference. You cannot have error checking on the USB audio connection if you don't have a buffer. If you don't have error checking, well...if some zeroes become 1 and the other way around, you loose from quality.

USB audio streaming != USB data transfer

- If your computer can't handle streaming audio a trillion dollar USB cable won't change that.

- USB receiver chips do have a buffer.

- Even isochronous transfer mode has error checking.

- If some bits flip you will most likely hear clearly audible glitches like nasty clicks or crackling noise and not a subtle degradation of quality.

 

So far pretty much all of what you're written is nonsense. Again, don't take this personal, it's a matter of facts.


Edited by xnor - 3/5/13 at 6:58am
post #1958 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

 

Well... both him and his wife participated. When one of them was listening the other one changed the cables. The one listening wrote his impressions down on paper.

That's what I would have assumed.  Problems here:  The cable swap time is way to long, and the test subjects (the guy and his wife) are only two subjects. I'll bet they did a handful of swaps then it got to be boring.  He needed at least 16 trials each, preferably 20.  Without more data, you can't reliably detect a trend.  And ideally the test should have been double-blind somehow.  Like a few of those swaps should have been just repeats of the same cable with the same swap timing to see if he still had a "preference".  Generally, double-blind testing determines if there is a detectable difference, and avoids picking a preference which by nature introduces bias.

 

Other issues...wife and gear in the same room with him? Acoustic sounds of cable changes might have biased the results. And what's really being tested for here is the possible interaction of two cables with two other specific devices.  It doesn't prove that USB cables have an audible difference in general anyway unless other devices are also used and tested the same way.

 

What his test with its limited data showed, sort of, was in an uncontrolled test with an unspecified number of trials, with two specific devices and two specific cables he claimed a preference.  And that's about all.  What we have is an opinion, not a tested principle.

post #1959 of 4174
Quote:
Originally Posted by xnor View Post

What I said has no logic, why?

 

What you posted makes little to no sense. Because:

- What you posted before are just anecdotes - if you don't know what that means read the definition of anecdotal evidence in a scientific context (also see my signature).

- You mentioned you found a really cheap USB cable, in the next sentence you say it costs $ 70.

- I do not take nonsensical claims personal and I'm not attacking persons, just nonsensical claims.

- If we want honest (not always the case) impressions that are not necessarily truthful we can go to the cables forum...

 

and:

- If your computer can't handle streaming audio a trillion dollar USB cable won't change that.

- USB receiver chips do have a buffer.

- Even isochronous transfer mode has error checking.

- If some bits flip you will most likely hear clearly audible glitches like nasty clicks or crackling noise and not a subtle degradation of quality.

 

So far pretty much all of what you're written is nonsense. Again, don't take this personal, it's a matter of facts.

 

I am not going to talk about your comparison with alien abduction as I think it is absurd 

 

If a frame contains an error, it waits for the frame to be resent. If the buffer is not big enough this may interfere with the timing.

 

 

Quote:
T’S NOT JUST ONES AND ZEROS, IT’S THE TIMING! 

There is a fundamental difference between the transfer of computer data and digital audio signals. Computers are able to transfer digital data without loss, because the data moves in the robust form of blocks, which do not depend on specific timing between the sending and receiving devices. However, digital audio signals are continuous streams of data, which are quite fragile, since the digital processor must remain perfectly locked onto the timing of the signal to avoid data losses.
 

 

 

Quote:
Originally Posted by jaddie View Post

That's what I would have assumed.  Problems here:  The cable swap time is way to long, and the test subjects (the guy and his wife) are only two subjects. I'll bet they did a handful of swaps then it got to be boring.  He needed at least 16 trials each, preferably 20.  Without more data, you can't reliably detect a trend.  And ideally the test should have been double-blind somehow.  Like a few of those swaps should have been just repeats of the same cable with the same swap timing to see if he still had a "preference".  Generally, double-blind testing determines if there is a detectable difference, and avoids picking a preference which by nature introduces bias.

 

Other issues...wife and gear in the same room with him? Acoustic sounds of cable changes might have biased the results. And what's really being tested for here is the possible interaction of two cables with two other specific devices.  It doesn't prove that USB cables have an audible difference in general anyway unless other devices are also used and tested the same way.

 

What his test with its limited data showed, sort of, was in an uncontrolled test with an unspecified number of trials, with two specific devices and two specific cables he claimed a preference.  And that's about all.  What we have is an opinion, not a tested principle.

 

 

It wasn't a professional test approved by an international organization of some sorts, I can give you that :)), but I think you exaggerate a little . I am just saying . I know a lot of people that noticed improvements brought by cables in general. You cannot just throw that aside. You can't say all the people that heard differences are victims of psichoacoustics. If they say they heard differences people put them to blind tests, if they hear differences in blind tests the results are cast aside, so practically whatever the results are, they don't matter to some people. 

 

However I respect their opinion.

post #1960 of 4174
Quote:
 I know a lot of people that noticed improvements brought by cables in general. You cannot just throw that aside. 

Yes, I can.  I know a lot of people who think they notice improvements in many things that aren't real.  Without proper testing, you actually can just throw that aside as biased opinion.

Quote:
Originally Posted by dan.gheorghe View Post

You can't say all the people that heard differences are victims of psichoacoustics. 

You mean Psychological influence.  Psychoacoustics is something else.  And until you eliminate all psychological influences from a test, it's not just testing the device, it's testing the entire situation, and anything in it that may bias the results, which end up simply as opinion, not scientific data.  You have to isolate what exactly you are testing for, and remove as many other sources of bias as possible.  Psychology is a very powerful influence, which is why in a real test, the choices being compared would be unknown, the switching time would be instantaneous, and there would be a third choice to try to match to A or B, which is equal to choice A or B, but randomized for each trial...A/B/X style.  Meaningful statistical analysis requires a lot of data...resolution if you like.  Under-sample, and you've got too much noise in the data to sort out a marginally detectable difference.  What if after 5 comparisons a subject identified a difference correctly 2 times?  Well, the test material he was listening to at that moment may have occluded the difference, and he's literally one more choice away from correctly "guessing" the match. But what if, after 20 comparisons the same subject identified a difference correctly 12 times?  He's had many more opportunities to "guess", or detect the difference.  He's now several votes away from significantly altering the outcome.  See, you have to have enough data to get the "noise floor" down and show a trend.

 

Quote:
Originally Posted by dan.gheorghe View Post
If they say they heard differences people put them to blind tests, if they hear differences in blind tests the results are cast aside, so practically whatever the results are, they don't matter to some people. 

 

However I respect their opinion.

As I pointed out, the test wasn't blind, unbiased, detailed, controlled or meaningful.  It is opinion, and so long as we all realize that, we can respect is as opinion.

post #1961 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

 

If a frame contains an error, it waits for the frame to be resent. If the buffer is not big enough this may interfere with the timing.

 

What are you saying here? That standard USB cables can't keep up with the voltage changes required to stream audio, but the more expensive ones somehow fix this? That the more expensive ones have buffers in them?

 

It's not an intelligent device. It's just transmitting voltage changes. And it can do so at a rate well above what you need to stream audio.

post #1962 of 4174
Quote:
And until you eliminate all psychological influences from a test, it's not just testing the device, it's testing the entire situation, and anything in it that may bias the results, which end up simply as opinion, not scientific data.

It would seem for any listening test, the perception of the individual is being tested-- not the device. 

post #1963 of 4174
Quote:
Originally Posted by JadeEast View Post

It would seem for any listening test, the perception of the individual is being tested-- not the device. 

Not of the conditions of perception are held constant and the device is changed.

post #1964 of 4174
Quote:
Originally Posted by jaddie View Post

Not of the conditions of perception are held constant and the device is changed.

OK, let me improve on that.  The test is to determine if there is an audible difference between devices.  Yes, auditory acuity and perception are involved, but held constant.  The variables, ideally, are the devices being compared.  

post #1965 of 4174
Quote:
Originally Posted by dan.gheorghe View Post

 

I am not going to talk about your comparison with alien abduction as I think it is absurd 

 

If a frame contains an error, it waits for the frame to be resent. If the buffer is not big enough this may interfere with the timing.

I think expensive (digital) cables are equally absurd, but that's just my opinion.

 

As for resending: that's simply not true. It's called USB audio streaming for a reason, it's a real-time system.

 

In isochronous transfer mode the USB bus sends frames every 1 ms (= 1000 Hz). If your computer can handle real-time audio streaming (which any properly configured PC can) each frame will contain the next 1 ms worth of audio data. If not there will be plainly audible glitches.

 

If a frame contains an error there is absolutely no attempt to resend anything. The sender doesn't care what the receiver receives, it just pushes the data in an as constant rate as possible. In fact, the receiver could not even tell the sender to resend anything because the communication is unidirectional. If bits flip the receiver could detect this using the checksum included in the frame, but there are only a few options (accept the erroneous data, replace it with silence or noise ...) how to deal with this situation, requesting the frame to be resent is not one of them.

 

The link you posted contains some nice marketing material, but that's about it.. the rest is nonsense.


Edited by xnor - 3/5/13 at 9:24am
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