ESS claim DAC pushes the boundaries of audio science, They claim results are supported by blind testing Options

[wakibaki]

Apologies if this topic has been posted previously, I did a search but found nothing.

http://www.youtube.com/watch?feature=playe...p;v=1CkyrDIGzOE

The above link shows a youtube video of an ESS presentation at RMAF.

Granted it is a sales presentation, it details advances ESS claim in the design of their sigma-delta DACs.

Foremost in the claims is the fact that some people can evidently hear features well below the noise floor which were previously held by the majority of engineers to be inaudible. This is said to be confirmed in blind testing.

Large changes in the values of variables in the state space are said to contribute to non-periodic steady-state noise normally invisible using conventional measurement techniques. This is visible when instrumentation is used to examine the Noise-vs-DC Offset.

This is said to be minimized in ESS products by techniques designed to control the state-space related noise by rapidly quenching state variable excursions.

ESS also claim that a further artifact of sigma-delta modulators, variable (non-linear) excess phase, which causes oscillation in S-D modulators, has been eliminated by making their devices unconditionally stable, and that this too contributes to greater acceptance of the devices by some listeners, although the reasons for this are apparently not clearly understood.

w

[Arnold B. Kruege...]

Apologies if this topic has been posted previously, I did a search but found nothing.

http://www.youtube.com/watch?feature=playe...p;v=1CkyrDIGzOE

The above link shows a youtube video of an ESS presentation at RMAF.

About 10 minutes into the presentation it misidentifies dither as noise shaping. How many more serious simple errors do I have to tally up before I justify not wasting any more time with it?

[2Bdecided]

About 10 minutes into the presentation it misidentifies dither as noise shaping.

No, he says the signal is dithering around, and puts the word dither in quotes. I think he knows full well it's not conventional dither he's talking about.


I can well believe the graphs he's showing. I would question audibility. I would question how the DAC responds to real-world signals. It's not just that it's hard to measure and show the (real) performance issues he's describing once you use real signals - it's that the noise in real signals randomises those problems so well that both measurement equipment and ears struggle to pick it up any more. There are/were SDM problems that did crop up in an apparently unpredictable ways with some real signals, but most companies believe those problems are solved.

It's a fascinating talk. There are some great, insightful examples in there (not least the very last one). However, he accepts the audibility of high (ultrasonic) frequencies as read, so...

I looked at the YouTube channel it's in - there are many other fascinating talks in the same channel (many from familiar names) which I wish I had time to listen to - but you will note very quickly that many of the people talking do not take the same approach to audio as HA - so while you may learn something, expect to find things that you totally disagree with...

http://www.youtube.com/user/RMAudiofest?feature=watch

Cheers,
David.