Ian Montgomerie
Stunt Coordinator
- Joined
- Feb 2, 2002
- Messages
- 112
A rather problematic assumption many SACD supporters seem to make is that the theory of DSD has much to do with what actually comes out the DACs of an SACD player. The fact is, any theoretical advantages of DSD over PCM are lost when, some time between the ADC in the studio and the DAC on your player, are lost when the music spends some time as PCM. When this happens, you really get the worst of both worlds. Because the music spent some of its life as DSD, you get flaws of DSD that PCM does not have, like inferior SNR at higher frequencies. And because the music spent some of its life as PCM, you get any disadvantages PCM might have relative to DSD.
And this basically always happens. If any post-processing on the music was done in the studio, they basically had to convert it to PCM to do it. They can only avoid that PCM stage if they do no post-processing whatsoever, it is basically straight from mike to tape (which is completely unworkable for many styles of music, and for 5.1 mixes). But even worse than that, the fact that the audio goes into the SACD decoder as DSD, and comes out as DSD, doesn't mean it was always DSD inside the decoder. Guess what, SACD decoders in players are no more able than SACD boxes in the studio to do post-processing directly on the DSD. What you have is a DSD->PCM stage, bass management is run on the PCM, then there is a PCM->DSD stage for output. (I don't know if there may be SACD decoders available which do no post-processing whatsoever, but if you have a chip which is even capable of bass management, dollars to donuts the bass management runs on PCM).
SACD as it is now is pure hype, because the theory of DSD is trumpeted over and over, but in actual recordings and actual players, any potential advantages are eliminated by PCM processing stages (while leaving the disadvantages). And it's not like this is some temporary setback. DSD domain post-processing is a whole new technological ball game. Even if SACD really takes off and people start to really invest in DSD post-processing technology, we're talking 5+ years before you'd have it be the norm in both studios and players. Without that, you're basically really limited in what you can do with the audio. Two channel only, since you won't really be able to create a good multichannel mix. No PP means most genres of popular music (as opposed to classical/jazz/etc) basically can't be recorded well, you would get no better than live-recording quality. And the player can't have bass management, so heaven help you if you have something other than two large main speakers positioned ideally, with analog-based volume control (and analog crossover for your subwoofer if you use one).
And this basically always happens. If any post-processing on the music was done in the studio, they basically had to convert it to PCM to do it. They can only avoid that PCM stage if they do no post-processing whatsoever, it is basically straight from mike to tape (which is completely unworkable for many styles of music, and for 5.1 mixes). But even worse than that, the fact that the audio goes into the SACD decoder as DSD, and comes out as DSD, doesn't mean it was always DSD inside the decoder. Guess what, SACD decoders in players are no more able than SACD boxes in the studio to do post-processing directly on the DSD. What you have is a DSD->PCM stage, bass management is run on the PCM, then there is a PCM->DSD stage for output. (I don't know if there may be SACD decoders available which do no post-processing whatsoever, but if you have a chip which is even capable of bass management, dollars to donuts the bass management runs on PCM).
SACD as it is now is pure hype, because the theory of DSD is trumpeted over and over, but in actual recordings and actual players, any potential advantages are eliminated by PCM processing stages (while leaving the disadvantages). And it's not like this is some temporary setback. DSD domain post-processing is a whole new technological ball game. Even if SACD really takes off and people start to really invest in DSD post-processing technology, we're talking 5+ years before you'd have it be the norm in both studios and players. Without that, you're basically really limited in what you can do with the audio. Two channel only, since you won't really be able to create a good multichannel mix. No PP means most genres of popular music (as opposed to classical/jazz/etc) basically can't be recorded well, you would get no better than live-recording quality. And the player can't have bass management, so heaven help you if you have something other than two large main speakers positioned ideally, with analog-based volume control (and analog crossover for your subwoofer if you use one).