DSD upsampling question (theoretical)

The logic of PCM upsampling by the “power of 2” makes sense.

But when upsampling to DSD, the upsampling is always set to go to 352.8kHz which isn’t by the “power of 2” for 48kHz or 96kHz files.

This is a theoretical question for me because I’m just playing around with Roon DSP settings and honestly can’t really discern a difference. It’s more “nerding out” than anything for me.

Is this “theoretically” insignificant that the upsampling isn’t by the power of 2? Would it be better to only upsample 44.1kHz files to DSD and just do standard PCM upsampling by “power of 2” for 48kHz and 96kHz files?

Curious and thanks in advance.

Are you talking about in a recording studio or in a program like Roon? I ask because upsampling to even the lowest DSD 64 give you a sample rate of 2.8 MHz, which is much much larger than 352.8 kHz.

On Roon. It upsamples to 352.8kHz before DSD256 conversion to 11.290Mhz

The 352.8kHz stage isn’t a “power of 2” conversion for 48 or 96kHz files.

Right, ok I understand now. I personally never though PCM audio upsampled to Power of 2 maximum sample rate sounded any better than PCM audio upsampled to a non Power of 2 maximum sample rate, at least not in Roon or Audirvana. I assume this is because they use the proper high quality filters, which can “estimate” interpolations of non power of 2 upsampling better than my brain can conceive. I think the first upsample PCM to DXD (32bit 352.8kHz PCM) before upsampling to DSD outweighs and deficits in audio quality that could be possible by using non power of 2 upsampling because the data in a DXD file and a DSD512 file have a close streaming data rate (according to Roon). I think that if poorly constructed digital filters were used, then the use of non power of 2 upsampling could possibly leave more of the quantization errors that occurs when converting between sample rates that are integer multiples of one another. I don’t know if I have ever heard this though, so I guess I don’t know if that would be audible or not.
What are your thoughts on this? I had never actually though about this before

I’m not smart enough or educated enough to really know. I just know that “in principle” you want to upsample by integers… so when I saw the upsampling of everything (44.1/48/88.2/96) to 352.8kHz I thought maybe I misconfigured something but there are no options.

The one option I have (as if I could even tell a difference) is to upsample only 44.1/88.2 to DSD256… while just using normal PCM upsampling for 48/96/192 files.

Again… just curious theoretically.

I don’t believe that for a second! It just takes a bit of time and a lot of reading and you pick things up. Plus, you thought of the question and I haven’t seen it discussed before on any forum before.

You did not misconfigure anything, so that is good. I think any difference you hear between PCM and DSD is going to occur regardless of the PCM originally being 44.1/88.2 or 48/96/192. I don’t think there is a need to only upsample certain files to DSD and not others, but if you try it out and you only like 44.1 PCM files upsampled to DSD 256 for example, then listen to it that way. You can get as theoretical as you want to (which is fun and I will do it all day long), but in the end it always just comes back to what you hear and prefer personally. We all hear differently anyway. I personally don’t like DSD and don’t upsample to DSD. I also don’t do much upsampling with PCM audio files either. Maybe up to 88.2/96 kHz at the highest.

This of course depends of the capabilities of your Dac.
In HQplayer you can upsample with Power of 2 (dependant on the chosen filter) and if your Dac can handle it.
My T÷A 8 DSD dac had 2 clocks, one for 44,1kHz multiples and one for 48 kHz multiples.
So my DSD upsampling respects Power of 2.
Conclusion: technically it is possible but not by Roon on itself AFAIK.
I doubt if it really matters, I cannot say that I hear some difference. Choice of filter (in HQplayer that is) makes a bigger difference.

+1, I agree

The “power of 2” option is only there for Roon’s PCM upsampling…

The option isn’t there for Roon’s DSD upsampling because Roon doesn’t support it at the moment.

Thanks @dabassgoesboomboom @Rugby @anon90297517 @AnimalOnDrums… I’ll keep playing around and testing different settings. I’m not sure I’ll be able to tell a difference and if that’s the case, I’ll stick with my current settings for DSD256 upsampling because… well, I guess I’m the guy the iFi DAC company was marketing to… the guy that likes to see the blue DSD256 or purple MQA LEDs light up as I’m listening to music. LOL.

Will keep pressing on and learning!

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LOL always good to see someone enjoying the music man.

I wonder why you get the interim step of upsampling to 352.8kHz. On my Roon machine, 44.1kHz tracks get upsampled straight to 11.290MHz, i.e. by a factor of 256. What does your Signal Path look like?

I think it’s because I’m using DSP for convolution filters too so it upsample for that then to DSD.