Up & Over Sampling... Continued

Megasam, I think the only difference Kevin Halverson pointed out is that the term "upsampling" has typically been used when speaking about a separate box placed between the transport and processor. That "upsampling" box is simply an oversampling digital filter, basically the same device located internally between the input receiver and the digital-to-analog convertor in a digital processor.

I don't want to sound ignorant about this because I feel I have a fair idea, conceptually, of how the digital process works. Let me quickly say that Garfish and others who spent their time researching this should be commended. Thank you for your efforts and sharing of information. While reading Mr. Halverson's response, images of Audio Alchemy's DTI-PRO32, Genesis Digital Lens, Camelot, etc. flashed through my head. Don't these devices act as the upsampling device? "Neither has any inherent advantage over the other, assuming both are done in a synchronous and integer fashion. The basic differentiation is that upsampling is an external process, oversampling is an internal one." He goes on to say that his product's don't have a need for that (and shouldn't for the $$$!) But when used with "poorer performing converters" increase their performance (to AS good?). Now here's where my ignorance comes in; Would a good D/A converter (under $2K) mixed with an outboard that had a great clock for low jitter, and added dither to the word length (like afforementioned products) be equal to THE BEST D/A converters? Let's also assume that they are in "a synchronous and integer fashion" I assume this is between the "upsampling converter" and the "oversampling converter". Is this like an I2 bus, firewire, digital coax? Or does this mean they need to be on the same digital frequency (i.e. 96KHz,128KHz,etc.)? Now don't anyone jump on me for this, it's just what I came away with from this discussion and Halverson's e-mail. Thanks.

Hi Treyhoss; It seems to me that you may be trying to "unscrute the unscrutable". Each of the components you mention would probably sound different from the others, and you would just have to try it to see if it provided any improvement. And then of course it would be in the context of the rest of your system. I personally think where these outboard upsamplers would be really worth while would be when used with less expensive CD players (as KH noted), but as the quality of the DA conversion process increases, the value of the outboard upsamplers becomes less important-- just my guess. I'm sure much of the technology used to actually build these components is proprietary-- whether they cost a few hundred dollars or thousands like the dCS gear. Cheers. Craig.

Craig, What's he trying to do to me? ;-)

Treyhoss, don't forget the analog output section. You could have two digital systems with identical digital conversion processes and parts and they could still sound considerably better/worse/different because of how the analog section is implemented. As for the "synchronous and integer fashion", I'm not exactly sure what is meant by synchronous (though I'm very sure Kevin Halverson does). The integer portion just means that the oversampling should be carried out as an integer multiple of the incoming data rate (eg. 44.1 x 4 = 176.4, 48 x 4 = 192, 44.1 x 8 = 352.8, 44.1 x 16 = 705.6), not a fractional multiple. I'm kind of curious about the synchronous part. Anyone got an answer? Live the good life, Jordan