Upsampling. Truth vs Marketing

Mathematically, there are no differences between upsampling and oversampling. Upsampling is basically a marketing term and it is NOT coincidental that it was conjured up during the redbook lull prior to DVD-A format agreements. Really, what is so special about 96kHz or 192kHz?? Why not 88.2kHz or 176.4kHz? For that matter, why not 352.8kHz or 705.6kHz? The choice of resampling a 44.1kHz signal to 96kHz or 192kHz is entirely about piggy-backing on the new high rez formats for marketing purposes. In fact, there is potential for loss of information by resampling assymetrically rather than by integer multiples.

Please refer to Charles Hansen (Ayre) or Madrigal, or Jeff Kalt (Resolution Audio), or Wadia, or Theta. All have made multiple statements that upsampling is nothing more than a marketing tool. Maybe it's good for high end in this sense...certainly high end redbook CD sales jumped after the "upsampling" boom. Magazine reviewers seemed eager to turn a blind eye since their livelihood depended on a healthy high-end market. Waiting 2-5 years for decent universal players certainly wasn't attractive, nor would reviewing the latest $20k redbook CD player when the general consensus at the time was that even bad high rez would blow away great redbook.

Sean, in fact, Jeff Kalt of Resolution Audio was marketing and using "upsampling" in his players at the time, so yes I do think some manufacturers will be honest when asked directly.

But more to the point, what do you think is so magical about 96kHz or 192kHz? Why not 88.2 or 176.4 or 352.8? I think the obvious answer is that the high rez format in DVD-A is either 96kHz or 192kHz...marketing anyone??

If you could, would you please contrast your upsampling dot graph with the equivalent oversampling dot graph? Remember that to get to 96kHz from 44.1kHz in your example you have to increase the number of dots from 20 to 43.5 dots. What you described is essentially a 2x oversampling routine with linear interpolation. The graph cannot get any smoother than the original unless you use something other than linear interpolation. Yyou are just connecting a series of dots in a line between samples, otherwise.

The main reason for adding points between the original samples is ultimately allow a more gentle analog filter. The original (really bad souding) CD players used no oversampling and analog brick wall filters to avoid the problems associated with the Nyquist limit for 44.1kHz sampling (22.05kHz) and the spurious images that get reflected back in band. These sounded horrible and led to 2X, 4X, 8X etc oversampling moving these images well beyond the audio band and allowing more gentle (better sounding) analog filters.

To paraphrase Charles Hansen, adding another digital filter (upsampling) to the chain will affect the sound; however it is certainly possible to design a single digital filter with exactly the same composite characteristics as the two cascaded filters, usually justs costs a little more money.

Anyway, not trying to be a pain in the a$$, I just think the marketing component of the choice for 96kHz or 192kHz needs to be pointed out.