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Up, over, and resampling

I tried asking this elsewhere and got a few anecdotes (more are always welcome), but I was really hoping for some links to technical papers (that I may not fully grasp. I haven’t kept up my college calculus.)

Does anyone have links to educational articles or papers on upsampling, oversampling, or resampling? I know there’s no new information generated, but it still theoretically helps DAC performance, right? Is there a downside as long as the implementation is solid? And what qualifies as correct?

I had a CD player many years ago that had an upsampling add on board. Impossible to quickly A/B, but it certainly seemed to enhance the experience enough that I had zero regrets with the upgrade. I think it converted redbook CD to 24/192. So I’ve had a positive early experience, But I see NOS DACs are crowed about, while there are others embracing a more is better approach  

I’m trying to research a little because I finally got around to reading some of the manual for my new streamer. (So I don’t screw up ripping all my CDs for, hopefully, the last time.) I realized it has options for resampling during playback. If I’m using the USB output it always sends at 32bit but can also goose PCM up to 8x (384kHz max). S/PIDF output is bumped to a maximum of 24/192. I don’t hear a big obvious difference, but I haven’t spent much time looking for one either. Without any DSP down the chain is resampling really worth it? And if I were to some day splurge and get an M Scaler or similar would it make sense to disable any resampling by my streamer in favor of a presumably better dedicated component?

Because it will be asked. My virtual system is mostly current. CD player was an Ah! Njoe Tjoeb, that was mothballed years ago when the transport started getting twitchy. The streamer is an AURALiC Aries G1.1. DACs are Chord Qutest or Soekris dac1421.

cat_doorman
erik_squires
16,056 posts
 

https://www.stereophile.com/asweseeit/344/index.html

Whoops my bad. I only got Oversampling half way correct. It does NOT interpolate, that part I was correct about, what I missed is that the intermediate samples are all at 0.

Also, I agree with the following statement, that the best thing these filters do is slightly tweak the top octaves:

So while I strongly suspected that the improvement I heard with the dCS 972 was simply due to its using a different oversampling filter, along with the benefit of better downstream DAC behavior when fed a 24-bit rather than a 16-bit signal—as I described in my January 1996 review of the Meridian 518—I wasn't sufficiently sure to spill ink on the subject.

mbmi's avatar
mbmi
568 posts
 

Non oversampling ( Audio Mirror) is sooooooo Sweeeeeeeeeet.

cat_doorman OP
237 posts
 

@yage I appreciate the extra homework. A reading list is what I was ideally looking for, There’s too much about the subject (even if you exclude disinformation) to cover it properly on one of these threads. I’ve skimmed through some talks by Rob Watts, but I assume having a better background prior will make those flow a little better.

@barts the CDs are being ripped to lossless FLAC. Any manipulation beyond redbook isn’t saved to disc. I had done ALAC before when I was still using a lot of iTunes, but that disc died a tragic death so I only have AAC copies of most of what was there. Those are fine for my phone, but not for my main rig. The first time I ripped was to fit all my CDs to an iPod, the old kind with a HD. Then I tried local streaming, lossless files over Airplay, but could never get the Airport Express to behave. Reboot at least once a day. Now after a few years of streaming lossless from Qobuz, it’s time to get everything on the streamer SSD. And I will back it up. I also need to decide which of the albums I mistakenly bought off iTunes as mp3s are worth buying again either on CD or digitally.

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