DSD conversion - why do it twice?

Roon Software Discussion
1

Hello,

Curious why Roon converts DSD64 to 352.8khz then again downsamples to 176.4?
The streamer I use here has a max sample rate is 192khz. Surely Roon is able to do one conversion process to 176.4khz, which I’d imagine be better for sound quality?
The DSP Sample rate converter is set to disable, but enabling it and choosing DSD64 to 176.4khz conversion does not disable the first step conversion Roon does.

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2

does not look like that on mine:

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3

@mavmcl, you are converting PCM to DSD, the OP’s system is setup for DSD to PCM.

4

I believe that DSD to PCM conversion is best done to the “native” rate of the DSD.

After that, Roon is performs any sample rate / bit depth conversations that are required to be compatible to the connected DAC.

6

I would assume that it is better to do the conversion from DSD to the highest PCM rate possible, and then, convert down to the target rate.

Awhile ago, I seem to remember a post by @brian who described the 2 stage process as being better for CPU usage.

7

Two stage is normal, indeed. Here’s how I see it:

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JCR

8

Understand it’s not a bug in Roon, but asking what’s the reason for the double PCM conversion. Is it better for audio quality?

9

I don’t think it has any, or at least not an significant effect on SQ. I think Roon does it that way because it takes fewer computing resources. You can see this if you watch the conversion speed in the signal path window.

You can have Roon convert directly from DSD to 176 in one step in your “DSP>Sample Rate Conversion” setting - choose to activate “enable native DSD processing” and Roon will convert directly to PCM 176.

But this is fairly resource intense and some PCs have difficulty with it.

10

Thanks for the reply. I don’t have that the ‘enable native DSD processing’ option in DSP. Perhaps, because my dac is not DSD compatible.