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Milind Kunchur Blind Cable Test

amirm

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From his conclusions: ". This work shows that two system configurations differing ONLY by the interconnect pathway are audibly discernable, even by average listeners".

So he doesn't consider the change from balanced out/in electronic circuits to unbalanced between the 2 tests as a difference in system configuration? Talk about amature science. His work shows nothing.
That is precisely what I post in my comment which got deleted by AES moderator. I tried to contact that moderator but his email alias is defunct and my email to him bounced. :(
 

Cbdb2

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Like they know he's wrong and your right. When the AES is acting like an audio rag time to look else where. Too bad.
 

Blumlein 88

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To me what is interesting is an unexpected result. I know about Kunchur's baggage and have been critical of his other tests. In this case if you had asked would there be an audible difference in this setup between RCA and XLR connections I think almost everyone would have said no. Yet his results indicate there was, and it must have been rather large for people to get the level of correct answers over long listening sessions separated over a rather large amount of time between comparisons.

Would be nice if he did better measurements of the two conditions. Would be nice if he used a really good ADC to record the output of the two conditions playing the music and compared them using Deltawave. I don't see a good reason for the two conditions to be audibly different. One would think the noise in the RCA version is the issue, but I'd be rather surprised if that has audio band noise at a level that is audible.

The DAC was Berkely Audio Alpha series 2. The Series one was measured by Amir, and it is a good DAC. The power amp was a Spectral which is also a good amp. Both perform very well with RCA or XLR inputs. I've known people with both and owned a Spectral myself. Where is the difference coming from?
 

dc655321

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To me what is interesting is an unexpected result.

Fully agree. It is certainly interesting.

Under more open scrutiny, I would be astonished if there was not a mundane factor in play (eg: noise transfer).

I was a bit put off though by the plots of noise spectra in the paper - attention to the audio band was suspiciously passed over.
 

amirm

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The DAC was Berkely Audio Alpha series 2. The Series one was measured by Amir, and it is a good DAC. The power amp was a Spectral which is also a good amp. Both perform very well with RCA or XLR inputs. I've known people with both and owned a Spectral myself. Where is the difference coming from?
I spoke with one of my contacts who is familiar with both and he said there is no assurance that the XLR and RCA outputs behave the same.

The biggest issue here is replication: the DAC is out of production. I contacted Berkley folks even and they don't have one either.
 

amirm

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If we can find the pieces, we can do the testing right with proper measurements and listening tests. This is needed but I don't know how we find the gear to do it per above.
 

Blumlein 88

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@1audio was a designer of the early Spectral gear. Don't know if he did the 250S (probably not), but maybe he can give an idea if the RCA and XLR would be appreciably different.

I agree there is no guarantee of RCA=XLR, but I'd think most quality gear has such a small difference it wouldn't matter audibly.

Of course nothing like getting the gear and measuring it to find out.
 

SIY

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I would recommend that anyone interested read Randi’s account of Targ & Puthoff experiments.

Besides the obvious test setup difference, controls snd data handling could be a question and would need examination. It’s a pity, but Kunchur’s baggage here demands a Baysian approach.
 

CinDyment

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I know that people have stated, with links, that Kuncher made many mistakes in this paper:

Thread showing inaccurate measurements:

However, I have not seen why his blind test was invalid. Can someone point to an issue where he may have allowed a sighted A/B comparison, or where the dB level was off?

We are often told to “do a blind test”, and I’m assuming no one is asking for detailed mathematical formulas, just the method of conducting the test and the results.

Thanks in advance.

He didn't compare cables. He compared single ended to differential and never once validated the end to end signal integrity. He is a charlatan plain and simple.
 

Blumlein 88

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I would recommend that anyone interested read Randi’s account of Targ & Puthoff experiments.

Besides the obvious test setup difference, controls snd data handling could be a question and would need examination. It’s a pity, but Kunchur’s baggage here demands a Baysian approach.
Well certainly approaching something Kunchur wrote about audio my priors put the probability of it being correct are pretty low.
 

Blumlein 88

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He didn't compare cables. He compared single ended to differential and never once validated the end to end signal integrity. He is a charlatan plain and simple.
He validated frequency response, noise and levels. The only thing that stood out is higher noise of the RCA cable, but it seems at too low a level in the audible band to explain the results.
 

CinDyment

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He validated frequency response, noise and levels. The only thing that stood out is higher noise of the RCA cable, but it seems at too low a level in the audible band to explain the results.

Did he? Read much closer. Did he truly validate end to end including at full signal level? Read very carefully what he actually did. There is no end to end validation. It's piece meal. I take it back. Not a charlatan. A fraud.

Again read clearly. He makes a ludicrous test of cable noise and cable bandwidth with fake loading. There is no end to end system validation. None. It's a joke.
 

egellings

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With a balanced cable you have 2 amplifier stages operating out of phase, (I'm ignoring transformer-based output sections). With a single ended cable, just one amplifier stage is involved. So, when comparing the two cable types, the cable is not the only thing you are changing.
 

JRS

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You are wrong.
My guess is that it is then a mixed boat. I have reprints of the Neville/Thiele/Small papers as a for instance, and never having had a subscription, have not been exposed to the gamut. So I did the next best thing and used google scholar so that I can at least see abstracts, and then picked a handful of topics (convolution, imaging distortion) which fetched thousds of papers, all seemingly with a highly technical bent.

Personally, had I been a referee, I would have sent it back to the authors suggesting some methodological improvements, hence my surprise that it was published in the current form.

Or is shoddy science the norm these days?
 

clearnfc

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So there are differences between cables?

I would say its impossible to tell unless you listen and discern it yourself. Electrical properties are easy to measure and its largely similar. However, one thing that cannot be measured is psychoacoustic effect (at least for now).
 

sam_adams

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With a balanced cable you have 2 amplifier stages operating out of phase, (I'm ignoring transformer-based output sections). With a single ended cable, just one amplifier stage is involved. So, when comparing the two cable types, the cable is not the only thing you are changing.

Balanced connections use inverted polarity on one signal conductor. The signals are in phase. Phase is a manifestation in the time domain.
 

CinDyment

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In phase, out of phase, does not matter. Read the paper carefully. He never measured the performance of the signal chain, not for balanced, not for single ended. He measured the cables. It is a total BS paper.
 

SIY

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Balanced connections use inverted polarity on one signal conductor. The signals are in phase. Phase is a manifestation in the time domain.
Balanced means equal impedance on each leg. One leg could be completely passive.
 
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