Octave Records - why only DSD64 available for purchase?

Hi @Paul

Why are Octave Records releases limited to DSD64 (SACD)?

Are they not recorded at higher DSD rates like DSD128? If so, why can’t we purchase these higher rates?

DSD64 is technically not very good - when nothing else was available it was fine but now we have higher rate recording abilities?

https://positive-feedback.com/audio-discourse/raising-the-sample-rate-of-dsd-is-there-a-sweet-spot/

https://dsd-guide.com/dsd-new-addiction-andreas-koch#.X7InRC0Rrq0

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According to his figure 2, the inherent noise of standard rate DSD is -140dB at 20,000Hz, -130dB at 30,000Hz.

Are you claiming your system reproduces this noise and you can hear it?

You are only looking at things at the digital side… there is also the analogue filtering required… as per his articles.

The gist of his articles is higher DSD rates like DSD128 makes analogue filtering easier (but there is a sweet spot in performance, something in between DSD128 and DSD256).

With something like an RME ADI-2 PRO FS A/D, recording in DSD128 and DSD256 is easy these days.

So if we can do technically better and it’s easy, why not?

No problems with releasing SACD discs for those that want disc but why not record at DSD128 and sell those files to those that wish to have them?

Like NativeDSD.com offer

These questions are to Paul, not you…

If we only look at things in the digital domain like you have here, then there is no technical reason for @tedsmith to upsample in DS DAC higher than DSD64 rate…

But the technical reasons are given there by Ted’s friend Andreas there…

There are multiple noise floors that matter here. The graph shows noise from nonlinear issues with sigma delta modulation.
That graph was produced by a averaging multiple FFTs each of which has many points (to get the desired frquency resolution.) If a million point FFT is used it will average white noise over a million bins and hence lower the apparent white noise power by 60dB. Also since multiple FFTs are averaged, white noise is also lowered by the square root of the number of FFTs that were averaged.
The purpose of these graphs is to make sure that non-white noise is clearly shown, but to get an idea about the white noise you need to know how many points were used in the FFTs and how many separate FFTs were averaged.

Double rate DSD allows moving the knee of the rise of nonwhite noise up an octave, quad rate another octave… BUT, higher sample rates are also compromised by more jitter which adds more “ugly” noise everywhere. So there is a sweet spot that depends somewhat on the other parameters of your implementation.

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Which makes perfect sense. Thanks.

Does not the upsampling of the DSD avoid the increased jitter issue while at the same time taking advantage of more relaxed filtering?

It is the risk you take when posting publicly; the public may respond. :slight_smile:

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That’s what you call “a good one” (slaps knee) :stuck_out_tongue_closed_eyes:

That’s precisely why there’s a sweet spot. With the DS that sweet spot for lowest quantization noise vs. jitter noise is somewhere just above double rate and below quadrate.

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Thanks, Ted. I’ll get my head wrapped around this eventually - I hope.

There are other reasons to like double or quad rate for upsampling - the more frequency room you have the more options for tailoring the noise floor or other tradeoffs. With single rate DSD the options are fairly constrained.

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This makes sense.

Fascinating stuff.

I’m listening to 16/44 WAV. Am I meant to have an inferiority complex?

Mozart violin sonatas. Lovely.

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Not at all! I think the Format thing is no longer terribly relevant in most applications, unless chasing whatever the Ultimate Current Thing is matters to you for some reason. I’m usually blissfully ignorant of what the sample and bit rate is of whatever I’m listening to. It has been a decades-long road during which that was a lot more relevant, and so it is a big relief.

I think it’s one of those “if you think it’s better than it is better” irregardless of the physical measurements one way or the other. Kind of like wires :smile: