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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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Dynamic
post Jan 23 2013, 19:22
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There's some plausible stuff in there, but then he's been asked to remove all mathematics, meaning it's rather difficult to work out if there's anything of true substance. The man himself claims to have degraded hearing and to be unable to tell the difference.

Without details of the DBT, I'd remain only open to actual valid evidence should any be forthcoming, but unconvinced they have anything to show either that other manufacturer's Sigma Delta DACs are poor or can be ABXed against linear additive DACs.

He did give the name of a colleague who would provide more information by email if requested. Not sure I'm motivated to bother, though.

The analogy of a stock broker whose results you're averaging breaks down in many ways because you're using oversampling deliberately and filtering the sound for proper reconstruction of a signal with defined bandwidth without introducing false staircasing/aliasing artifacts in the analogue output, because the DAC should have upsampled and shaped the noise to eliminate any false frequency content between the input's Nyquist limit and the gentle analogue low-pass reconstruction filter somewhere above 22 kHz. There's no signal that's trying to invert the reconstruction filter to overcome its effect and force through signals of 30kHz, say, to create incorrectly sharpened edge responses that exceed the proper Nyquist limit. Daily closing stock prices do not have an intrinsic frequency response and represent no physical reality, just a record of prices paid with no specific time intervals. He did admit that he thought up that non-mathematic analogy that morning, so I can't blame him for trying, but it's still there on YouTube over a year after the conference and it deserves to be debunked as being non-applicable to the proper band-limited reconstruction of audio signals.

There's a further presentation immediately after, about digital vs analogue volume controls and about jitter, notionally, albeit more to do with failure to synchronise the DAC to the source clock rate and sustain proper synchronisation of the decision time. He admits that the jitter displayed at first is greatly exaggerated to display it clearly on a graph, then fails to say why with real jitter (much smaller time variations) a PLL is insufficient if it actually locks to the PHASE of the signal and thereby follows the true clock frequency and phase (or even an integer multiple of the clock frequency if that's required for synchronising Sigma-Delta operation), as it should.

The only problems arise if you start to insist on synchronizing to a clock that's internal to the DAC but is not itself synchronized to the source clock. That shouldn't be necessary unless you're making the DAC act as a mixer or something, for sources with different clocks. It's definitely not a problem if the DAC is provided with the same source clock directly, as it is in most consumer equipment with internal DACs, which means the exceptions are standalone DACs and those within Receivers provided with digital input, which must use that input to derive their clocks.
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- 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 hasnít 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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