AES Paper on SACD vs CD

Posted: Fri Nov 02, 2007 9:04 am

At last, a paper in a definitive journal. My AES membership is worth the price. Reading it now.
http://theaudiocritic.com/blog/index.php?op=ViewArticle&articleId=41&blogId=1

Posted: Fri Nov 02, 2007 9:12 am

Some more details of the experiment here.
http://www.bostonaudiosociety.org/explanation.htm

Posted: Fri Nov 02, 2007 10:34 am

Grrrrrrrrrr.

I want to see more details.

Posted: Fri Nov 02, 2007 10:39 am

That is a good article.

Posted: Fri Nov 02, 2007 10:54 am

Doesn't the 16bit down conversion nullify any of the benefits of a higher resolution recording? It doesn't seem like a logical comparison.

Posted: Fri Nov 02, 2007 3:32 pm

You need to read the AES paper, but they put a 44/16 A/D/A into the playback stream from an SACD player and no-one could tell the difference from hundreds of double blind tests with hundreds of subjects including pro audio folk.

The methodology seems fine and it passed the AES review committee. Now it remains to be seen whether it can be reproduced by others duplicating the methodology.

I love it, its cat amoung the pigeons time.

Posted: Fri Nov 02, 2007 3:54 pm

So...let me get this right (I haven't paid my AES dues in nearly 10 years...)

They put a CD against an SACD, but in the SACD chain they had a 16/44.1 PCM converter?

Or are you saying that they double blind tested the raw sound of a SACD (through DSD converters straight into playback) against the raw sound of CD?

I've done my own blind tests with members of one of the orchestras I record (same exact signal going to both the computer and the DSD recorder) and 8 out of 10 of the musicians I selected chose the DSD recorder as the better sound.

I'll see if any of them would be able/willing to come here on the boards and "testify."

What makes me VERY suspect of this is, supposedly MANY people can hear minute differences in converter from brand "a" to brand "b." That's why Lavry Gold and DCS are in business. If this is the case, then they're also saying that there is absolutely no discernable difference in converters in general since clearly two different A/D chips and likely different analog circuitry would have been used!

Something smells here!

(But then again, it wouldn't be the first time I completely disagreed with findings published in the AES journal - one reason I haven't paid up in so long!)

Posted: Fri Nov 02, 2007 4:07 pm

Nothing smells. They put a 44/16 A/D/A into the playback stream from an SACD player. They referred to it as the 44/16 "bottleneck". It was switched in and out, double blind. At levels ranging from 85-92dBL replay, no-one could tell the difference with it in or out.

Posted: Fri Nov 02, 2007 5:12 pm

Unless my logic is loose, it would seem this panel would also not be able to discern a live mix feed from its a/d/a "bottle-necked" version. As Cucco mentioned, they are not just listening to DSD vs 1644 formats. They are also hearing the analog circuitry of the SACD player, the ADC, and finally the DAC.

That they were unable to differentiate between the equipment (much less the pcm conversions) seems rather fantastic.

Having said that, I can't say I feel that SACD is a sonic quantum leap from a quality controlled RedBook CD.

Posted: Fri Nov 02, 2007 6:12 pm

Quote:

I can't say I feel that SACD is a sonic quantum leap from a quality controlled RedBook CD. -- Zilla

That's maybe the bottom like to it...

Posted: Sat Nov 03, 2007 3:10 pm

There is one major flaw in reasoning in this paper that is blatantly laid out in the first paragraph. As a practicing statistician, I feel compelled to point it out:

"They prove beyond a shadow of a doubt, with literally hundreds of double-blind listening tests at matched levels, conducted over a period of more than a year, that the two-channel analog output of a high-end SACD/DVD-A player undergoes no audible change when passed through a 16-bit/44.1-kHz A/D/A processor. That means there’s no audible difference between the original CD standard (“Red Book”) and 24-bit/192-kHz PCM or 1-bit/2.8442-MHz DSD."

You cannot prove the absence of an effect in statistical inference (i.e. when sampling from a reference population....that includes you and me....)

Posted: Sat Nov 03, 2007 4:26 pm

That is not stated in the paper Michael. That is from the blog entry about the paper.

Posted: Sat Nov 03, 2007 4:53 pm

David, as I don't seem to have access to the paper, would you mind spelling out their exact conclusion?

Posted: Sat Nov 03, 2007 5:07 pm

DavidSpearritt wrote:

That is not stated in the paper Michael. That is from the blog entry about the paper.

OK, thanks for the clarification. If so,The Audio Critic has a ways to go before they achieve their stated claim of "accountability in audio journalism".... I'd settle for a little accuracy in reporting!

Still want to read the paper...

Posted: Sat Nov 03, 2007 5:44 pm

Zilla wrote:

David, as I don't seem to have access to the paper, would you mind spelling out their exact conclusion?

Exact conclusion reproduction is impossible for obvious reasons. The paper is readily available for a nominal fee from aes.org.

Their paraphrased conclusion is that using ABX double blind tests with 4 different hi-res audio players containing a switchable 44/16 bottleneck in the output stream, through 4 different systems, all replayed at pink noise calibrated 85dBL level, over 500 subjects, men, women, students of audio, age and backgrounds well represented, no better than chance was obtained for detection of the bottleneck.

Some info here.
http://www.bostonaudiosociety.org/explanation.htm

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