Monday, December 6, 2010

CD/DVD Player Oversampling DACs

I had purchased a Sony CDR-375 due to having seen a plug about its definitely has a crystalline top end, smoothed midrange, and an overall strangely shifted character. I noted that it has a 4558 op amp in the output, which is old and slewy (which is great for certain things). Definitely not a "wide bandwidth/clean" opamp, for program purposes...

This machine must be oversampling. I've since acquired a few older Sony CD players, and note timbral differences, with the 1993 unit being pretty honest (but a bit gritty in the top).

Discussion in the fora pointed to oversampling as the culprit. Two to four-times oversampling seems to shift upwards the overall spectrum, due to increased timbral density. Even congas and female voices seem to have a slightly higher fundamental (or the energy is upwardly shifted due to new overtones??). I found that this messes with the balance of a drumset (real or electronic). Dead Can Dance's "The Fatal Impact" has a nice balance between synth conga and synth kick drum, a nice, stumbling dread. I did not enjoy how it changed on an oversampling machine. I tap my toes and move a little to this beat, I like it a lot; don't mess with it, don't change the original intent of the music.

I note that some things benefit (the guitar and overall "snap" of Diana Krall's wonderful "Live in Paris"), but other things do not, as might be concluded/expected. C-Tec's "Cut" will peel the skin and hair from your face and skull. You didn't need that anyway.

One DIYer posted that a friend brought over a CD of his drum playing. Upon hearing it on the other system, he stated bluntly (and truly), "That's not my drumset." The DIYer had a setup allowing for the selection of sample rates, and upon selecting 44.1/16, the player was satisfied. I will surmise that this is the rate and depth at which it was originally recorded, etc.

Some players have SPDIF and optical out, allowing the use of external DACs; some of them are specifically non-oversampling, yet are capable of it with additional hardware (the OPUS from, and sport the most modern converters with truly extreme specs. Because it's DIY, you can find out for yourself.