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Help! Sacd Good Or Bad?, Does SACD ought to sound like crud?
Joe Bloggs
post Sep 9 2002, 12:33
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I've listened to SACD once and it sure sounded good...

I've heard people say that SACD ought to fail in transient reproduction, (because it can only encode a rise and fall relative to the last time step) so I did some calculations:

'Sampling rate' of SACD = 2.8MHz = 64x 44.1kHz

For encoding tones up to 44.1kHz at full scale, it has to reach full-scale from 0 in 64 steps, that is, at any given time there can only be 64 possible positions for the waveform.

This gives it 6 bits resolution to CD's 16 bits??

OK, suppose you only need to encode up to 22.05kHz at full scale, the number of possible positions increases from 64 to 128--7 bits resolution, big improvement blink.gif

I doubt this is how DSD actually works, but this article http://www.iar-80.com/page40.html (I linked to page 40, but it seems page 1-39 may be going on and on about the sonic flaws of DSD as well) seems to take this view seriously and goes on to talk about how you try to recover musical information from the 6 bit stream. blink.gif
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Kim_C
post Sep 11 2002, 02:51
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QUOTE (KikeG @ Sep 10 2002 - 11:27 PM)
QUOTE (Joe Bloggs @ Sep 10 2002 - 03:01 PM)
I thought the reason to go hi-res is pretty much universally agreed on: to move the Nyquist frequency further from the upper ceiling of human hearing so that lower order filters can be used instead of brick wall filters, which are problematic any way you design them.

I don't think brickwall filters are problematic today. On the other side, SACD is problematic in other ways, as explained here.


Well.... they still might be problematic...

Ryohei Kusunoki published article on 1996-97 at Japanese MJ magazine about Non-Oversampling and Digital-Filter-Less DAC Concept.
He states that: "the issue is not either it is Non-Oversampling or Higher-rate-sampling, but the use of the digital filter can cause smearing in the time domain".

Arcticle is available here in english: http://www.sakurasystems.com/articles/Kusunoki.html

Here is interview from 1999 where he tells of his further research on subject: http://www.tnt-audio.com/intervis/kusunoki_e.html

In interview he says:
"I found the answer after listening to a DAC using eight DAC ICs to bring about 8-times oversampling without digital filter. The DAC's sound clearly indicated that oversampling was not the culprit of sound degrading, but the real offender was the digital filter."

"Digital filters cut off signals beyond 20kHz with a very steep curve, but needs around 2msec of time to calculate the enormous data. I think this is the reason of "diffusion of sound coherence", the characteristic tonal quality of the oversampling DAC"


47 Laboratory DAC's Model 4705 Progression and Model 4715 Shigaraki implement Kusunoki's ideas by using zero oversampling and they don't have any filter at all, no digital or analog. Here is info about them:
http://www.sakurasystems.com/products/47dac.html
http://www.sakurasystems.com/products/shigadac.html


There are some other High-End DAC's which follow this "school of thought" by using 0-oversampling and analog filter instead of digital one.
Audio Note Dacs are most famous of them: http://www.audionote.co.uk/dacs/dac_index.htm

On Audio Asylum thread "Non-oversampling DAC concept", Audio Note's Peter Qvortrup says that they started developing the 1xoversampling DAC concept in 1995, first functional prototype was tested in early 1996 and Audio Note UK built and shipped the first 1xoversampling DAC5 in August 1997, a full three months before Mr. Kusunoki's article was published. Thread is here:
http://www.audioasylum.com/scripts/t.pl?f=...digital&m=18753
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Posts in this topic
- Joe Bloggs   Help! Sacd Good Or Bad?   Sep 9 2002, 12:33
- - Joe Bloggs   Ok, um, does DSD assume delta modulation or delta-...   Sep 9 2002, 13:33
- - Peter   well, some people are apparently having problems w...   Sep 9 2002, 13:50
- - Joe Bloggs   Problem is, the bits are not employed in the same ...   Sep 9 2002, 14:15
- - Joe Bloggs   This is an example of Sigma-Delta, or Pulse Densit...   Sep 9 2002, 15:16
- - Jasper   The general idea is correct, but SACD quality does...   Sep 9 2002, 16:29
- - Joe Bloggs   So the encoding system is really just plain delta ...   Sep 9 2002, 16:39
- - Jasper   Sorry to have confused you, I didn't have a go...   Sep 9 2002, 16:54
- - 2Bdecided   IIRC, the difference between delta and sigma-delta...   Sep 9 2002, 17:49
- - n68   yup... call it what you wan`t... (i assume...   Sep 9 2002, 18:24
- - mcg1969   I don't think you can fairly say that SACD is ...   Sep 9 2002, 23:42
- - Frank Klemm   QUOTE (2Bdecided @ Sep 9 2002 - 06:49 PM)IIRC...   Sep 10 2002, 01:25
- - crazyboy_T   > - Very critical signal needs time resolution ...   Sep 10 2002, 04:22
- - n68   QUOTE (mcg1969 @ Sep 9 2002 - 10:42 PM)I don...   Sep 10 2002, 10:44
- - Pio2001   QUOTE (crazyboy_T @ Sep 10 2002 - 06:22 AM)Is...   Sep 10 2002, 11:47
- - Frank Klemm   QUOTE (crazyboy_T @ Sep 10 2002 - 05:22 AM)...   Sep 10 2002, 11:57
- - 2Bdecided   It's possible to detect an interaural time del...   Sep 10 2002, 12:36
- - petracci   QUOTE (2Bdecided @ Sep 9 2002 - 06:49 PM)Howe...   Sep 10 2002, 14:53
- - Joe Bloggs   QUOTE Another point: I have serious doubts about t...   Sep 10 2002, 15:01
- - Joe Bloggs   OT: I'd finally figured out what the correct g...   Sep 10 2002, 15:09
- - KikeG   QUOTE (Joe Bloggs @ Sep 10 2002 - 03:01 PM)I ...   Sep 10 2002, 21:27
- - bryant   QUOTE (Joe Bloggs @ Sep 10 2002 - 06:09 AM)OT...   Sep 10 2002, 22:33
- - Kim_C   QUOTE (KikeG @ Sep 10 2002 - 11:27 PM)QUOTE (...   Sep 11 2002, 02:51
- - Artemis3   So in other words, the answer to the thread's ...   Sep 11 2002, 04:19
- - Joe Bloggs   Huh? Plain DVD does 24/96? What's DVD-A for th...   Sep 11 2002, 05:42
- - bryant   QUOTE (Joe Bloggs @ Sep 10 2002 - 08:42 PM)Hu...   Sep 11 2002, 05:52
- - Joe Bloggs   Any DVD-A records with DRM?   Sep 11 2002, 06:45
- - bryant   QUOTE (Joe Bloggs @ Sep 10 2002 - 09:45 PM)An...   Sep 11 2002, 07:12
- - Joe Bloggs   Oh, I mean, any DVD-As without audible watermarks?   Sep 11 2002, 07:37
- - n68   QUOTE (bryant @ Sep 11 2002 - 06:12 AM)All DV...   Sep 11 2002, 08:08
- - bryant   QUOTE (Joe Bloggs @ Sep 10 2002 - 10:37 PM)Oh...   Sep 11 2002, 09:24
- - Pio2001   QUOTE (Kim_C @ Sep 11 2002 - 04:51 AM)Audio N...   Sep 11 2002, 11:46
- - Joe Bloggs   So would you agree with this kind of design? What...   Sep 11 2002, 13:33
- - ChristianHJW   Sorry for stepping is so late .... DVD-A vs. SACD ...   Sep 11 2002, 14:26
- - Frank Klemm   QUOTE (ChristianHJW @ Sep 11 2002 - 03:26 PM)...   Sep 11 2002, 14:54
- - user   DVD-Video: Theoretical PCM possibilities for DV...   Sep 11 2002, 14:55
- - ChristianHJW   QUOTE (Frank Klemm @ Sep 11 2002 - 01:54 PM)I...   Sep 11 2002, 15:11
- - Joe Bloggs   OK, so non-oversampling DACs use analog filtering ...   Sep 11 2002, 15:29
- - ChristianHJW   .. arent most modern DACs using a combination of d...   Sep 11 2002, 15:37
- - Kim_C   QUOTE (Pio2001 @ Sep 11 2002 - 01:46 PM)For w...   Sep 11 2002, 16:43
- - Joe Bloggs   What troubles me is that I don't even know wha...   Sep 11 2002, 16:51
- - Pio2001   QUOTE (Joe Bloggs @ Sep 11 2002 - 05:29 PM)Ca...   Sep 11 2002, 20:12
- - Frank Klemm   QUOTE (Joe Bloggs @ Sep 11 2002 - 06:42 AM)Hu...   Sep 11 2002, 20:49
- - KikeG   About non-oversampling filters, I have to say that...   Sep 12 2002, 00:45
- - Kim_C   QUOTE (KikeG @ Sep 12 2002 - 02:45 AM)About n...   Sep 12 2002, 13:53
- - 2Bdecided   I've heard David Chesky's 6 channel 24/96 ...   Sep 12 2002, 14:33
- - KikeG   In reply to Kim_C: It is true that human ear cann...   Sep 12 2002, 14:49
- - Kim_C   QUOTE (KikeG @ Sep 12 2002 - 04:49 PM)This do...   Sep 12 2002, 15:20
- - Kim_C   QUOTE (2Bdecided @ Sep 12 2002 - 04:33 PM)P.S...   Sep 12 2002, 15:52
- - Joe Bloggs   QUOTE (2Bdecided @ Sep 12 2002 - 09:33 PM)P.S...   Sep 12 2002, 16:20
- - KikeG   QUOTE (Kim_C @ Sep 12 2002 - 03:52 PM)"b...   Sep 12 2002, 16:51
- - ChristianHJW   QUOTE (KikeG @ Sep 12 2002 - 01:49 PM)In repl...   Sep 16 2002, 12:41
- - Joe Bloggs   I would also think that you're most likely to ...   Sep 16 2002, 13:03
- - KikeG   QUOTE (ChristianHJW @ Sep 16 2002 - 12:41 PM)...   Sep 16 2002, 18:56
- - Pio2001   QUOTE (ChristianHJW @ Sep 16 2002 - 02:41 PM)...   Sep 16 2002, 23:25
- - ChristianHJW   it was an analog filter i had done using a few op-...   Sep 17 2002, 10:39
- - fewtch   Sheesh... all of this started from an original que...   Sep 17 2002, 10:49
- - Pio2001   QUOTE (ChristianHJW @ Sep 17 2002 - 12:39 PM)...   Sep 17 2002, 11:32
- - fewtch   bleep   Sep 17 2002, 12:12
- - KikeG   QUOTE (ChristianHJW @ Sep 17 2002 - 10:39 AM)...   Sep 17 2002, 12:32
- - ChristianHJW   QUOTE (KikeG @ Sep 17 2002 - 11:32 AM)In the ...   Sep 17 2002, 13:31
- - Joe Bloggs   He said analog filter. The most likely explanation...   Sep 17 2002, 16:01
- - KikeG   QUOTE (ChristianHJW @ Sep 17 2002 - 01:31 PM)...   Sep 17 2002, 17:17
- - Pio2001   QUOTE (KikeG @ Sep 17 2002 - 02:32 PM)You can...   Sep 17 2002, 22:40
- - ChristianHJW   QUOTE (KikeG @ Sep 17 2002 - 04:17 PM)It is a...   Sep 19 2002, 13:56
- - KikeG   Well, I was just intending to explain that this ...   Sep 19 2002, 22:18
- - DickD   Regarding the airy sensation, I concur with KikeG....   Feb 11 2003, 14:41
- - robUx4   QUOTE (KikeG @ Sep 19 2002 - 10:18 PM)About f...   Mar 3 2003, 15:00
- - ChristianHJW   QUOTE (robUx4 @ Mar 3 2003 - 02:00 PM)We basi...   Mar 3 2003, 15:35
- - 2Bdecided   Most of the ideas that are being kicked around her...   Mar 3 2003, 16:02
- - user   http://www.hfm-detmold.de/texts/de/hfm/eti...ten/s...   Mar 3 2003, 16:04
- - ChristianHJW   QUOTE (user @ Mar 3 2003 - 03:04 PM)So, they ...   Mar 3 2003, 16:28
- - Frank Klemm   QUOTE (2Bdecided @ Mar 3 2003 - 05:02 PM)Most...   Mar 3 2003, 19:25
- - robUx4   That would be a very interresting stuff. How many ...   Mar 4 2003, 00:09
- - Pio2001   I've got a 24/96 soundcard, and HD 600 Headpho...   Mar 4 2003, 01:06
- - KikeG   I agree pretty much with Pio's explanations an...   Mar 4 2003, 09:46
- - KikeG   QUOTE (robUx4 @ Mar 3 2003 - 03:00 PM)... but...   Mar 4 2003, 09:50
- - Canar   This is completely off-topic, but I just wanted to...   Mar 4 2003, 10:15
- - robUx4   I just wanted to add something to my paleonthologi...   Mar 4 2003, 10:41
- - Pio2001   QUOTE (robUx4 @ Mar 3 2003 - 05:00 PM)The hum...   Mar 4 2003, 12:29
|- - user   interesting study and paper about difference betwe...   Mar 24 2006, 15:26
- - Pio2001   I remember having read this. It must have been dis...   Mar 24 2006, 16:27
- - SebastianG   I wonder why they have chosen 176,4 kHz at 24 bits...   Mar 24 2006, 16:58
- - Pio2001   Probably to stay close to real-world applications.   Mar 24 2006, 17:36


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