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Originally Posted by KMO /forum/post/0
By it's very nature, it's basically impossible to do anything to a 1-bit DSD signal without doing some calculations in multi-bit form. It can only be "pure" if you don't bass manage at all. Even doing a 1-bit calculation introduces more noise - every requantisation to 1-bit adds to the noise levels.
The question is - is the intermediate form high enough resolution for it not to matter too much? The Sony chip does its calculations in "DSD-Wide" (2.8MHz/8-bit). This is much higher-resolution than the general PCM paths in general receivers, and maintains the transient response, so in theory it should do a better job of bass managing the signal than the receiver could (at 192kHz/24-bit).
I'm no engineer (or scientist, for that matter--just an historian) but I've read several articles over the years that basically say any such "resolution" comparisons are really apples vs oranges. Even within the PCM camp, if you will, debates go on about what constitutes "hi-res". I've found the most compelling arguments to be those that maintain bit-depth is quite a bit more important than sample rate (so 16 bit/ 192 khz would NOT be hi-res, but 24/48 (or even 24/44.1) would be hi-res). If I were to apply that logic to DSD, then even "DSD wide", at 8 bit, would NOT be hi-res. But, even 1 bit DSD IS hi-res, so clearly we cannot make simple calculations/comparisons of that nature.
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I'd agree that all the equipment gives the impression that time alignment is even harder than bass management for DSD. Leaves me totally stumped though. Don't understand the problem at all.
I'd say the pure DSD path is more likely to be used when playing 2-channel only. There are a lot of high-end audiophile 2-channel SACD players out there that won't be going through any sort of nasty, dirty home-theatre receiver.
I agree regarding 2 channel "pure DSD". That is the most accessible way to experience "pure DSD" (the MCH gear/placement necessary for "pure DSD" is prohibitive in space and/or cost for just about everyone). All that said, I've done level matched comparisons in 2 channel of pure DSD vs the A/D/A of my receiver (I set the speakers to large, sub OFF and activated the A/D/A of the receiver on the MCH inputs--my receiver has 192/24 Wolfson DACs) and I found no difference that did not require a level of concentration I would NEVER employ, even for critical listening. I've also tested the MCH w/BM of each and there, I found a clear favourite as the xover slope of my receiver is steeper than that of the player. That trumped the "Sony chip" found in my player (a Marantz DV6400--not the last word in hi-res, of course, but a capable audio player when new, comparable to the Denon DVD-2900 for audio, if not video). Lastly, I compared playback with and without time alignment and, again, a clear favourite emerged. Steeper xover slope + time alignment + DSD>PCM conversion + A/D/A sounds better in my room (without full range speakers and space constraints preventing an ITU configuration) than the "pure DSD" path. Would I like a "pure DSD" path? Sure. But even with my Frankenstein's mess, both SACD and DVD-A are clearly better than redbook CD (where the mastering and recording quality are of high standards for each).