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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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wakibaki
post Jan 23 2013, 21:04
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One of the 'golden ear' claims that has been hotly disputed is that there are audible features in reproduced music which are not revealed by conventional measurements.

ESS claim (if I interpret the video correctly) that they now measure a feature that was not previously thought significant (not part of a conventional audio measurement suite), and (if you take the claims at face value) that modifying this feature has audible results. If anyone has experience of DAC development I would appreciate their comments on this.

This leads to the possibility that other audible features exist which are not revealed by a conventional audio measurement suite.

ESS moreover claim that they have discovered (in blind testing) a further modification which is audible but for whose audibility they currently have no explanation (and evidently no capacity to detect by measurement, or none that they revealed). This is some way of imposing unconditional stability which they can turn on and off for the purposes of DBT in an FPGA implementation of the DAC.

Ultimately this has no philosophic impact on DBT, but if it is true, it will undoubtedly eventually set the cat among the pigeons, so those who like to depend on the idea that instrumented measurement as it stands, will reveal any audible feature, better be ready for the shitstorm, if and when it arrives.

Thanks for your comments so far, Dynamic.

This post has been edited by wakibaki: Jan 23 2013, 21:06


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Dynamic
post Jan 23 2013, 21:49
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QUOTE (wakibaki @ Jan 23 2013, 20:04) *
Ultimately this has no philosophic impact on DBT, but if it is true, it will undoubtedly eventually set the cat among the pigeons, so those who like to depend on the idea that instrumented measurement as it stands, will reveal any audible feature, better be ready for the shitstorm, if and when it arrives.


I think these are the sorts of extraordinary claims that require at least ordinary evidence to be taken very seriously. By ordinary, I mean DBT with some details of methodology and identification of the equipment under test. We can't simply accept it on authority and claim to be skeptically astute.

Some of the talk may inadvertently have set up straw men and demolished them, some of it may have genuine evidence behind it that hasn't been sufficiently revealed to allow an objective assessment of its merits or otherwise.

They have provided some measurements (e.g varying the DC offset level - not sure where they're doing so and whether it's in sub-LSB amounts or what) that provided some measurable spikes, so the idea that it's beyond measurement is not necessarily supported. Whether it's simply a failure to apply adequate dither or some other flaw that they're displaying, I really can't guess. They don't provide enough information, though they hint that it's often fleeting and dynamic during transitions, not often visible in steady state conditions and not especially visible on waveform plots either. I dare say it would be visible with appropriate FFT comparisons of a good ADC capture of the DAC output (e.g. an digital sampling oscilloscope or a good audio ADC running at, say 48 kHz 24-bit). Having a digitized capture would allow a variety of FFT lengths and alignments to identify features in question.

Perhaps someone needs to take a few screen captures and timings from the YouTube video to help us discuss certain points without making everyone sit through an hour's lecture. Then again, without enough evidence, perhaps it's not worth pursuing unless ESS substantiate it further.

The guy sounds for the most part like someone who really knows what he's talking about but is trying not to reveal trade secrets and not to use any mathematics in front of a lay audience. He does mention some patent numbers on some of the points he bring up in one of the two videos, but I forget which of them it was. He says that ESS normally don't present to enthusiasts as they're usually involved only with industry and don't produce products sold directly to consumers. He might also be loathe to go into details that might normally be discussed only under a commercial non-disclosure agreement.

Personally, I'm not that inclined to take it that seriously for now, as there are so many audio companies providing measurements that are irrelevant to audibility and I've no clue whether any DAC I'm using would potential sound like the un-named purpordetly less-than-transparent sigma-delta DAC and whether it's enough for me to care either for my own less-than-audiophile use case or out of technical curiosity.

This is an audio forum thankfully devoid of unsubstantiated claims (thankyou TOS#8), and these claims remain tantalizingly short of substantiation from what I've seen. If the fine folks at ESS would care to substantiate them further, they might be worth a look, but we don't even know what devices they're claiming are deficient so they're unsubstantiated and from the information provided unverifiable. If anyone takes a look at the patents mentioned and finds something plausible, I might be interested. I might do so myself if I have time to spare, but I'm not greatly inclined to do so.
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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 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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