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ESS claim DAC pushes the boundaries of audio science, They claim results are supported by blind testing
wakibaki
post Jan 23 2013, 04:23
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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.

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Arnold B. Kruege...
post Jan 24 2013, 14:28
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QUOTE (wakibaki @ Jan 22 2013, 22:23) *
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?
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2Bdecided
post Jan 24 2013, 18:50
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QUOTE (Arnold B. Krueger @ Jan 24 2013, 13:28) *
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.
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Arnold B. Kruege...
post Jan 25 2013, 13:15
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QUOTE (2Bdecided @ Jan 24 2013, 12:50) *
QUOTE (Arnold B. Krueger @ Jan 24 2013, 13:28) *
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.


Please provide the time in the video where that takes place.

Maybe we're not watching the same video, because the one I'm watching starts mentioning noise shaping at 8:02, but the slide' graphic shows dither. The slide specifically mentions noise shaping, and AFAIK dither has not been mentioned at all at this point. Actually, the voice comments at that point seems to be describing the operation of a successive-approximation converter. But the slide says quite clearly "Noise shaping".
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2Bdecided
post Jan 25 2013, 13:53
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QUOTE (Arnold B. Krueger @ Jan 25 2013, 12:15) *
Maybe we're not watching the same video, because the one I'm watching starts mentioning noise shaping at 8:02, but the slide' graphic shows dither. The slide specifically mentions noise shaping, and AFAIK dither has not been mentioned at all at this point. Actually, the voice comments at that point seems to be describing the operation of a successive-approximation converter. But the slide says quite clearly "Noise shaping".
If you use low order noise shaping without dither, it'll look a bit like those graphs. The graphs are clearly drawn in a graphics package, not real (he's got the step size wrong on the green "noise shaped" graph for one thing), but he is showing noise shaping.

Of course, he could equally well be showing lousy dither. If you think you can tell the difference between an artistic representation of non-optimal dither, and an artistic representation of low order noise shaping, then can I respectfully suggest that you don't know what at least one of them really looks like.

Cheers,
David.
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Arnold B. Kruege...
post Jan 25 2013, 16:35
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QUOTE (2Bdecided @ Jan 25 2013, 07:53) *
QUOTE (Arnold B. Krueger @ Jan 25 2013, 12:15) *
Maybe we're not watching the same video, because the one I'm watching starts mentioning noise shaping at 8:02, but the slide' graphic shows dither. The slide specifically mentions noise shaping, and AFAIK dither has not been mentioned at all at this point. Actually, the voice comments at that point seems to be describing the operation of a successive-approximation converter. But the slide says quite clearly "Noise shaping".
If you use low order noise shaping without dither, it'll look a bit like those graphs. The graphs are clearly drawn in a graphics package, not real (he's got the step size wrong on the green "noise shaped" graph for one thing), but he is showing noise shaping.


Can't be.

Just to remind you, here's a really pretty good definition of noise shaping from Wikipedia:

"
Noise shaping is a technique typically used in digital audio, image, and video processing, usually in combination with dithering, as part of the process of quantization or bit-depth reduction of a digital signal. Its purpose is to increase the apparent signal to noise ratio of the resultant signal. It does this by altering the spectral shape of the error that is introduced by dithering and quantization; such that the noise power is at a lower level in frequency bands at which noise is perceived to be more undesirable and at a correspondingly higher level in bands where it is perceived to be less undesirable. A popular noise shaping algorithm used in image processing is known as ‘Floyd Steinberg dithering’; and many noise shaping algorithms used in audio processing are based on an ‘Absolute threshold of hearing’ mode
"

The key part of this definition is "Its (noise shaping) purpose is to increase the apparent signal to noise ratio of the resultant signal. It does this by altering the spectral shape of the error that is introduced by dithering and quantization; such that the noise power is at a lower level in frequency bands at which noise is perceived to be more undesirable and at a correspondingly higher level in bands where it is perceived to be less undesirable."

The long and the short of it is that noise shaping takes place in the frequency domain. Until one shows something going on in the time or frequency domain, they aren't sensibly talking about noise shaping.

Since the diagram he shows is clearly in the amplitude domain, he is not sensibly talking about noise shaping. My most charitable judgement is that he was talking about dithering even though his discussion of pump gas prices sounded more like a discussion of successive approximation.

Bottom line, I think this guy was giving a mish-mash of every lecture and book he ever read or heard about DACs, about all 3 of them (!!!), jammed aimlessly into something that made sense to him, but can't actually make sense to anybody who has a proper understanding of what he was conflating and muddling through.

This post has been edited by Arnold B. Krueger: Jan 25 2013, 16:38
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Posts in this topic
- wakibaki   ESS claim DAC pushes the boundaries of audio science   Jan 23 2013, 04:23
- - saratoga   DACs were a solved problem ten years ago so I...   Jan 23 2013, 05:28
- - phofman   The claim would have been much more credible if th...   Jan 23 2013, 08:13
|- - wakibaki   QUOTE (phofman @ Jan 23 2013, 07:13) The ...   Jan 23 2013, 18:36
- - pdq   I haven't watched the video, but if the DBT th...   Jan 23 2013, 18:54
|- - Dynamic   pdq, it wasn't all about hearing below -96 dB ...   Jan 23 2013, 20:10
- - Dynamic   There's some plausible stuff in there, but the...   Jan 23 2013, 19:22
- - Willakan   During the presentation on jitter, the ESS guy als...   Jan 23 2013, 20:40
|- - Banned   QUOTE (Willakan @ Jan 23 2013, 21:40) Dur...   Jan 23 2013, 21:01
- - wakibaki   One of the 'golden ear' claims that has be...   Jan 23 2013, 21:04
|- - db1989   QUOTE (wakibaki @ Jan 23 2013, 20:04) Ult...   Jan 23 2013, 21:25
|- - Dynamic   QUOTE (wakibaki @ Jan 23 2013, 20:04) Ult...   Jan 23 2013, 21:49
|- - Arnold B. Krueger   QUOTE (wakibaki @ Jan 23 2013, 15:04) ESS...   Jan 24 2013, 14:12
- - Dynamic   I think inter-aural timing differences under 1ms c...   Jan 23 2013, 21:13
- - greynol   Until positive DBT results can be repeated by an i...   Jan 23 2013, 21:38
|- - wakibaki   QUOTE (greynol @ Jan 23 2013, 20:38) Unti...   Jan 23 2013, 23:14
|- - greynol   QUOTE (wakibaki @ Jan 23 2013, 14:14) If ...   Jan 23 2013, 23:25
||- - wakibaki   QUOTE (greynol @ Jan 23 2013, 22:25) Fall...   Jan 24 2013, 02:09
||- - pdq   QUOTE (wakibaki @ Jan 23 2013, 20:09) No,...   Jan 24 2013, 03:06
||- - Nessuno   QUOTE (pdq @ Jan 24 2013, 03:06) Last I k...   Jan 24 2013, 18:00
|- - saratoga   QUOTE (wakibaki @ Jan 23 2013, 17:14) If ...   Jan 24 2013, 02:56
- - Willakan   Pretty impressive typo in my earlier post: I meant...   Jan 23 2013, 22:36
- - greynol   Funny how it is you who gets to rely on words like...   Jan 24 2013, 02:46
- - greynol   ...until it is disproved that the Flying Spaghetti...   Jan 24 2013, 03:06
- - Arnold B. Krueger   QUOTE (wakibaki @ Jan 22 2013, 22:23) Apo...   Jan 24 2013, 14:28
|- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jan 24 2013, 13...   Jan 24 2013, 18:50
|- - dhromed   QUOTE (2Bdecided @ Jan 24 2013, 18:50) so...   Jan 25 2013, 11:50
||- - 2Bdecided   QUOTE (dhromed @ Jan 25 2013, 10:50) I...   Jan 25 2013, 13:56
||- - 2Bdecided   QUOTE (2Bdecided @ Jan 25 2013, 12:56) I ...   Jan 25 2013, 17:59
|||- - Arnold B. Krueger   QUOTE (2Bdecided @ Jan 25 2013, 11:59) QU...   Jan 25 2013, 19:28
|||- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jan 25 2013, 18...   Jan 25 2013, 19:49
||- - dhromed   QUOTE (2Bdecided @ Jan 25 2013, 13:56) QU...   Jan 26 2013, 00:19
|- - Arnold B. Krueger   QUOTE (2Bdecided @ Jan 24 2013, 12:50) QU...   Jan 25 2013, 13:15
|- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jan 25 2013, 12...   Jan 25 2013, 13:53
|- - Arnold B. Krueger   QUOTE (2Bdecided @ Jan 25 2013, 07:53) QU...   Jan 25 2013, 16:35
|- - benski   QUOTE (Arnold B. Krueger @ Jan 25 2013, 11...   Jan 25 2013, 17:24
|- - 2Bdecided   QUOTE (benski @ Jan 25 2013, 16:24) What ...   Jan 25 2013, 17:55
||- - benski   QUOTE (2Bdecided @ Jan 25 2013, 12:55) an...   Jan 25 2013, 18:22
||- - Arnold B. Krueger   QUOTE (benski @ Jan 25 2013, 12:22) QUOTE...   Jan 25 2013, 18:27
||- - 2Bdecided   QUOTE (benski @ Jan 25 2013, 17:22) QUOTE...   Jan 25 2013, 19:44
|- - Arnold B. Krueger   QUOTE (benski @ Jan 25 2013, 11:24) QUOTE...   Jan 25 2013, 18:21
- - Willakan   There's certainly no shortage of contentious c...   Jan 24 2013, 22:28
|- - Hotsoup   QUOTE (Willakan @ Jan 24 2013, 14:28) ......   Jan 24 2013, 22:46
- - 2Bdecided   This one is quite interesting... http://www.youtub...   Jan 25 2013, 11:12
- - Woodinville   Digital will not sound like analog until we start ...   Jan 25 2013, 11:13
- - db1989   If he hasn’t had his lunch yet, his blood glucose ...   Jan 25 2013, 18:30
- - 2Bdecided   QUOTE (db1989 @ Jan 25 2013, 17:30) If he...   Jan 25 2013, 19:51


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