Originally Posted by blissmusic
DSD is simply 1 bit PCM? I thought there was a completely different architecture from PCM to a delta-sigma modulation scheme such as DSD? Am I right?
No, not quite. Not even close, really.
In the early days of digital audio (like, over a decade ago), ALL of our A-D conversion was done with 1-bit delta-sigma modulation at 64x (2.8224MHz) conversion. That info was then decimated to 44.1K, and converted to 16bit (then later, 20bit, and 24bit as the benefits of higher bitrates became obvious in the processing stages).
Right there, you see there is nothing "new" about DSD-stylie conversion. 1-bit delta-sigma modulation at 2.8224MHz has been used from the very beginning of digital audio. And, yes, it was PCM then, and it still is PCM. OK...
Later in the evolution of digital audio, convertor design engineers got hip to the fact that 1-bit conversion cannot be dithered, and that means noise, lots of it in the high freqs, which made all those peeps who claimed early digital audio sounded harsh and nasty - well, they were right. It did sound kinda rough because you cannot dither a 1-bit signal...and so where does all that quantisation noise go?? Well, you have to try to push it up out of the audible band, and they tried but that sh*t got reflected back into the audible band in the form of 3rd-order harmonic distortion. And that distortion cannot be removed once it's recorded, at all by any means...and that distortion GOT there because the conversion was at 1-bit (which cannot be dithered). Following me so far? Good...
SO, the convertor designers decided to re-design their convertors as multi-bit on the front-end of the digital stage of the convertor chip. Which meant they no longer had to deal with all that noise which is generated by an un-dithered A-D convertor (such as the ones used in DSD - which is still using the OLD OUTDATED convertor design). Convertor chip manufacturers such as Burr Brown, Crystal and AKM all switched over to this NEW multi-bit format. And digital audio began to sound much better as a result.
Oh, and before I forget: The NEW multi-bit convertors were ALSO delta-sigma modulation designs, just like the OLD 1-bit convertors were. Right? STILL delta-sigma, STILL PCM. Same as it ever was - as far as all THAT goes. Still with me? OK...
So now you know:
1) DSD is not new
2) DSD is PCM
3) DSD is not "different" in any sense, except...
DSD does not re-convert to multi-bit (uless it's "DSD Wide" in which case it's multi-bit and now you're back to the whole PCM thing...ARGH!), or down-sample from the 2.8224MHz sampling rate (and who the hell can hear at that freq - not to mention that freq will literally burn your tweeters - ARGH!).
Not to mention the fact that one cannot process (EQ, compress, edit, etc.) a 1-bit DSD signal (unless you convert it to multi-bit, and why not just do that at the recording stage anyway?), so forget about all that.