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In Reply to: OK... posted by ducati on April 27, 2003 at 07:35:57:
Here are some excepts from a paper presented to AES.--------------------------
At 750kHz the signal is only 10 dB down. Hence, it is clear that DSD as a carrier provides a signal bandwidth which exceeds 100kHz by far. Obviously, the SNR decreases for high frequencies.
As far as experimental evidence shows [17] the human auditory system is sensitive to ultra sound only if it is correlated with the signal in the 0-20 kHz band, hence, the increase in noise at high frequencies is not important. The excess in bandwidth can subsequently be used to allow for very slow low-pass filtering, which keeps the time response very accurate.
This effect is clearly illustrated in Fig.9. The impulse responses of 4 different systems in a multichannel configuration is depicted : a 48 kHz system, with a bandwidth of 20 kHz (that is, 8 kHz transition bandwidth is allowed for anti-aliasing filtering), a 96 kHz system with 35 kHz bandwidth (26 kHz transition bandwidth), a 192 kHz system with 75 kHz bandwidth (42 kHz transition bandwidth) and an SACD system with 96 kHz bandwidth. Though none of the systems reproduces the input exactly, the DSD system shows the least artifacts.
Clearly, the 48 kHz system has great difficulty in reproducing the click; due to the steep filtering it starts ringing at a -30 dB level approximately 1ms before the click, which is very audible. Also at the higher sampling frequencies, the rining phenomenon cannot be remove, though it is reduce significantly. Only the DSD system is very effective in suppressing the ringing effect, due to very slow filtering above 95 kHz.
....
read stuff about bit rates
....
Moreover, it is argued that the DSD format complies with the minimal requirements set by the human hearing system in order to avoid audible artifacts caused by digitizing the analog signal. For example, the minimal sampling rate needed is about 350 kHz, which is not covered by a 192kHz PCM recording. Moreover from 20 kHz and onwards the neccessary signal-to-noise ratio becomes increasingly less important, which is in concodrance which the natural behavious of a SDM. Due to the latter feature of DSD, the signal becomes very bit-efficient compared to existing PCM formats closest to the afore mentioned minimal requirements. These statements include lossless coding for both kinds of signals. For example, on SACD a 6-channel DSD recording of 95 minutes can be stores where for 20bit 192Khz PCM only 55 minutes can be stored.
http://www.sacd.philips.com/b2b/downloads/dsd_2.pdf
Follow Ups:
"This effect is clearly illustrated in Fig.9. The impulse responses of 4 different systems in a multichannel configuration is depicted : a 48 kHz system, with a bandwidth of 20 kHz (that is, 8 kHz transition bandwidth is allowed for anti-aliasing filtering), a 96 kHz system with 35 kHz bandwidth (26 kHz transition bandwidth), a 192 kHz system with 75 kHz bandwidth (42 kHz transition bandwidth) and an SACD system with 96 kHz bandwidth. Though none of the systems reproduces the input exactly, the DSD system shows the least artifacts.
Clearly, the 48 kHz system has great difficulty in reproducing the click; due to the steep filtering it starts ringing at a -30 dB level approximately 1ms before the click, which is very audible. Also at the higher sampling frequencies, the rining phenomenon cannot be remove, though it is reduce significantly. Only the DSD system is very effective in suppressing the ringing effect, due to very slow filtering above 95 kHz."This is highly misleading rubbish from the Philips AES paper.
Highly misleading and false assumptions.DSD isn't reproducing the click correctly either! The click is at -6dB from full scale input and in the presented graph you see .25 on the vertical scale. (-6dB is .5)
It's a mere 'coincidense' that he puls mimics the input pulse and not by dsd virtues.
It would be interresting to see how dsd copes with such a pulse at lets say -60dB from full scale.
Also the 3us pulse is outside the bandwith of the pcm sample rates.
(Sample duration for 192kHz is 5us) This alone make this 'comparison' invalid. Any idiot knows that the signal must be below 1/2*fs.
(The wine tasting habit must be gotten out of hand the evening before the day he cooked this one up!)This test is a fraud designed to made pcm 'look bad' by intention.
It proofs only that dsd is a blatand marketing lie.Another lie exposed:
"Clearly, the 48 kHz system has great difficulty in reproducing the click; due to the steep filtering it starts ringing at a -30 dB level approximately 1ms before the click, which is very audible."
Ringing at 24kHz is NOT very audible.
Frank
Why don't you submit a paper for peer review to the AES ? This might give what you say some credibility. I content that your comments are biased to cover up good research and proof that DSD is better than PCM 192/24.What about Meridian ? Their paper supports most of what is reported in the Philips white paper. Didn't they have something to do with DVD-A ? Or are they biased for SACD too ? How come they debunk your comments to ?
Maybe the truth is, you don't know what your talking about ;)
I'm not either. But that doesn't prevent me in spotting these blatand flaws in the AES paper.There is no proof in this document that dsd is better than 24/192 or even 24/96.
You are only fooling yourself.My only beef with dsd is that low 64*fs sample frequency. It should have been at least 128*fs.
You obviously missed the part about the pcm processing in the Sonoma and the Pyramix systems...
Frank
This is the DVD-A forum, and I've been a bit naughty argueing for so long here. So I'll leave you with the last word on that.Just out of interest, if we limited bandwidth to 8kHz, which would you prefer then ?
Daniel.
24 bits is more than sufficient resolution.The biggest advantage for pcm is still that digital processing is much simpler to implement.
Frank
Great link, thanks!I just don't agree with their self-imposed limitations. Ringing is audible, absolutely. And as you point out, each format has it's issues. Ringing is tremendously low at the 96khz and 192khz sampling rates, and I'm willing to live with that to have better fidelity in the audible band, with very little ringing at 192, than pay Sony licensing fees to use something quite obviously designed for multichannel..
And there you go. Absolute proof Sony doesn't care about the audiophile, but rather the home theatre crowd.
:)
Good discussion the past few days, good food for thought :)
I want to make clear that I think SACD is a good sounding format. I doubt, given equal equipment, whether I would ever hear enough of a difference between the two to choose one or the other. And ironically enough, though I don't agree with DSD and Sony's push for it, and truly believe it's yet another way for Sony to shake $$ out of our pockets (as the music companies and production houses will certainly pass on licensing costs to the consumer)... And hate the fact I can't use it personally... I most certainly will have SACD in my house. Since I own a dCS, and dCS isn't on board with the standardized IEE1394, and DVD-A doesn't have their act together with it... My only choice for hirez audio is SACD!
LOL ;)
I agree, DSD is not a home format and I wouldn't suggest for a minute that your 192/24 recordings are shit, I'm sure theyre brilliant.However, I take note with one, remember SACD mandates stereo, the disks for the first two years were all stereo. You can buy MONO SACD's.
My worry about DVD-A is not whether it can support stereo, we all know it can, and many (most?) disks do at the moment. However, we know Joe Bloe Sixpack doesn't give a shit and tends to like stuff which comes out of all speakers, since his speakers are never in the right space, so he doens't even know what "soundstage" is.
So, lets look into the future, DVD-A becomes the standard, CD is a distant memory.. they're filling the disks with the multi-media clips and photo albums... 24/96 Hirez 6-channel, DTS 96 6-channel, Dolby Digital ES 7.1 mix.... umm, theres not enough space for stereo on the disk, "WHO CARES" says MR. Beancounter, they can use the mixdown feature of their DVD-A. Its not that far away.
Yes, you can say Sony want $$$ for SACD, but
1) Theyre a commercial operation, theyre supposed to earn $$
2) Did you know that SACD fee's are less than half DVD-A fees ?But, No, you can't say they don't care about the audiophile, there is no watermarking, we have mandated stereo, because, even if SACD becomes popular, it will suffer from the same tendancy for "ping-pong surroud" on mainstream releases. At least I know I will get a regular stereo mix to go alongside it, as it is compulsary. Don't you agree ?
Finally, you say "I just don't agree with their self-imposed limitations." Which are these ? How is any other format not limit by the technology of the day ?
Daniel
mandating a 2CH mix and doing a good job of it are two different things. I agree that having 2CH mandated is a good idea - more so for the current situation then the long term. 2CH stereo was a limitation imposed on 3CH stereo due to the introduction of the LP (try a google search on W.B Snow for Bell Laboratories in 1933) so MCH is actually a good thing if done properly. Now if the mass market dictates MCH and the effort is spent making that the best mix, what is to stop them from taking short cuts in creating the 2CH mix? Unfortunately the market will drive how music is presented on both high-rez formats and if the majority of the market doesn't care about higher quality 2CH the effort to create a great 2CH mix will suffer. Small labels will remain in the game creating 'audiophile' recordings of both 2CH and MCH.
DVD-A or SACD: SACD by a slight margin. Long term tie.Then the watermarking issue. From what I see http://www.mpg.org.uk/watermarkingreport.htm SACD *does* have a provision for watermarking too. It could be that they have been clever enough not to implement the third type of watermarking for the time being to allow the format to become entrenched. Why ruffle any feathers if you can ignore it for the time being? Protection of the material is likely to happen but this will be at the option of the label.
DVD-A or SACD: SACD by a slight margin. Long term tie.
Since watermarking can be present on any audible signal, that means you can say LP supports audible watermarking. However, we know that realistically its not the case. Same with SACD.Thing is, with SACD Sony specifically designed it to be resilient without watermarking, its not part of the recommended specification, never was. It is the absoloute opposite for DVD-A, where until the last minute watermarking was compulsory and every player had to detect it, every disk had to include it. We know that every SACD doesn't had watermarking and that nearly every DVD-A title does (except for audiophile labels). So their is no need to debate this, the proof is in the pudding.
Finally, with regards to mandated stereo, if its compulsory, at least they'll have to include it. Given the fact that nearly every recording engineer understands the value of music and quality, chances are they will always include a quality mix. The Beancounters can't stop it being included. With DVD-A, Mr Beancounter can just say "We use MixDown, a valid part of the DVD-A specification for legacy 2-channel systems". For all historical recordings, there will always be a 2-channel mix in some format for them to include. For new recordings, well Stereo becomes less important, since they can be recorded well in 5.1 if that is what is intended. Still, if they are forced with a decision to appeal to mass market, they can always ensure the stereo mix is sorted for audiophiles. Mandated stereo always encourages them to do the right thing.
Daniel.
The watermarking is added as an option to the spec on request by the record labels representatives.Eventually they will use it for sacd as well.
Frank
They havn't so far.... rememeber, SACD can't be recorded at home and is a protected media. Now your grasping at straws.
It's a logical assumption.Philips demonstrated watermarking technology so it's there.
There are additional 'features' possible with watermarking.
-Tracking pre-release copy's leaking out of studio's.
-Royalty gathering from airplay.
-Control over (future) digital recording devices that read the
watermark.Frank
You may be right in the future, it is a valid path for things to take. However, its not the case at the moment, which is the important thing.Daniel.
Yes, absolutely; it angers me that DVD-A doesn't require 2-channel mixes. You are right to be afraid, I completely agree. I do love 5.1 for movies, but it has no place in music, IMO. ESPECIALLY with high bitrate material; 24/96 + and DSD 2-channel creates an enveloping, surround-like environment anyway (on a good rig). A few people at my home have even thought I had all 6 channels running, when in fact it was just the front two...The limitations I speak of is that I believe Sony developed DSD for multichannel; they always point out that 6 full DSD channels can be slapped on a disc. I don't care, Sony! I want 2 channels of absolute highest fidelity. THAT's the limitation I want to live by :)
I did hear SACD's fees are lower, but you forgot the DSD fees. Sony's licensing is SO DAMN EXPENSIVE for DSD, it makes the mastering chain incredibly expensive. That will get passed down, too. And 24/192 is FREE!! (if you buy the gear, LOL)!!
Remember, DSD is just a marketing term for PDM or SDM. Sony only own patents over a specific implementation.I agree, Sony developed DSD for Stereo + Multichannel on a single disk, with maximum compatability with CD. Unfortunately, it is what it takes for a medium to have a chance in this day and age.
One thing, remember even before SACD existed, DSD was originally developed as an archiving format for their masters..... given these are 100% 2-channel, this would indicate that DSD's specific design for multi-channel may not be supported by evidence.
As for prices being passed down, its so insignificant for record companies if its sells, SACD or DVD-A. In Australia, many of the hybrid SACD's have been priced even cheaper than full price CD!!! Some are a bit more, some at full price, and a few less. So the price arn't that bad. To be honest, I'm happy to pay if I get the quality.
With regards to Multi-channel, and this applies to DVD-A and SACD. If its done correctly, it does actually sound good. Tubular Bells for example, which was originally conceived for Quadrophonic sounds awesome on SACD (a 4.0 mix). I've also heard some excellent classical Piano solo SACD's which just used the rears for ambience and sound brilliant. I'm sure the quality DVD-A releases can be just as effective. So 5.1 doesn't have to be all bad, though you'll never be able to count on it always being used sensibly.
Daniel.
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