Thanks to everyone for responding to my thread. I've learned a lot, and there has been relatively little flaming. Here are my thoughts:
1) We need to be careful about what we are talking about. My original question was basically if there is a fundamental difference between single box optical CD players vs. network/hard disk players like the SB/Transporter (with the hypothesis that it was due to a lack of sufficient buffer to eliminate problems with jitter and errors). So points made about traditional CDPs as "transports" feeding external DACs are off topic and a whole other issue (given that you then have a SP/DIF cable, no clock being transmitted, etc., jitter can easily be introduced in that case). 2) The points made by Clive and others that the buffering of the bits coming off the optical disc and how they are clocked into the internal DAC of the CDP seem basically valid. I.e. that the bits are clocked out of the buffer by the master clock of the CDP into its DAC must basically eliminate any jitter from the optical drive, ASSUMING the clock is solid, and there are no interactions between the optical drive and the jitter of the clock. 3) Sean asserts that there are NO fundamental differences between an optically based player and a network/HD player like the SB. I see where he is coming from in one sense. The bits coming out of the optical player's buffer ought to be the same as the ones coming from the network, IF you exclude errors and error correction errors. This is because, as noted above, the stream of bits coming out of the optical buffer are controlled by the master clock that is also driving the DAC. 4) Nevertheless, my sense is still that there are often signficant sonic problems related to optical drives inside of single box CDPs. Perhaps not inherent, and perhaps high-end CDP makers get around the problems by including separate power supplies for motors and audio circuits, using data drives to have better error correction (which then requires bigger buffers), using higher quality DACs and clocks, etc. But still, my gut feeling is that there are a set of complex engineering compromises when working with a real-time delivery (i.e. not CD_ROM data) optical drives that **usually** compromise the sonics. 4a) I say this for two reasons. (a) my friends and my (admitedly unscientific) listening experience is that the SB has (while not always better overall) a reliably more pleasant, musical, and different sound than most CDPs (insert your favorite audio descriptors here: relaxed, focused, mo-better bass, smoother, blah, blah, blah), **especially for the money**. I know this will not satisfy the bits-are-bits folks, but my experience working in recording studios is that the ear/brain system is an extremely sensitive (though often unrealiable--hence the need for blind testing) measurement system that can discover differences that can't initially be explained in engineering terms. I think many here will remember when CD players first came out and people who said they didn't think the sound was that great compared to vinyl were ridiculed because CD audio was "perfect". My ears tell me something is wrong with traditional CDPs. 4b) Second, the whole optical real-time delivery system seems like kind of a mess. It's mechanical, it puts EMI producing, variable speed motors next to analog electronics, it is prone to data errors, it puts a strain on the power supply, etc. (I'm sure those who know more about the insides of this system can describe other problems). I think we've learned that both bits and analog audio are pretty fragile, and many factors can affect both. So moving all that optical junk off to an external computer (and eliminating the real-time getting bits off a crappy optical disc delivery problem completely), seems like a good thing. If nothing else, it makes for a simpler engineering problem and fewer compromises in a box like an SB. 5) Of course, there are all the convienience advantages, which also increase the pleasure of listening to music. Thanks again to everyone! .phil -- pvadbx ------------------------------------------------------------------------ pvadbx's Profile: http://forums.slimdevices.com/member.php?userid=5719 View this thread: http://forums.slimdevices.com/showthread.php?t=28621 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
