DSD vs PCM level difference

[Music1969]

Maybe @Miska can explain the difference in noise floor @pkane showed here:

Octave Music Don Grusin High Resolution Music Analysis (Video)

Here is a PCM1792 (Mono mode) outputting -150dB signal in DSD64 mode. For DSD256 shift the noise lower and to the right. No in band problems to see here. You cannot compare graphs with different configurations (FFT size and averaging) and different test signals (frequency and amplitude). These...

www.audiosciencereview.com

I guessed the background of -3dB noise floor difference is explained here:

 

[pkane]

Maybe @Miska can explain the difference in noise floor @pkane showed here:

Octave Music Don Grusin High Resolution Music Analysis (Video)

Here is a PCM1792 (Mono mode) outputting -150dB signal in DSD64 mode. For DSD256 shift the noise lower and to the right. No in band problems to see here. You cannot compare graphs with different configurations (FFT size and averaging) and different test signals (frequency and amplitude). These...

www.audiosciencereview.com

I guessed the background of -3dB noise floor difference is explained here:

View attachment 196852

I don’t get what point you’re trying to make. Analog output showed test signal at the same exact level for DSD and PCM. If noise was 3dB higher for DSD, that means SNR was 3dB lower. Miska’s own measurements showed the same:

https://www.audiosciencereview.com/...ution-music-analysis-video.31620/post-1138796

 

[Music1969]

I don’t get what point you’re trying to make. Analog output showed test signal at the same exact level for DSD and PCM. If noise was 3dB higher for DSD, that means SNR was 3dB lower. Miska’s own measurements showed the same:

https://www.audiosciencereview.com/...ution-music-analysis-video.31620/post-1138796

I guess the results you showed are completely expected based on the above screenshot I showed?

Nothing surprising for the different noise levels?

 

[bennetng]

I guess the results you showed are completely expected based on the above screenshot I showed?

Nothing surprising for the different noise levels?

Being a Miska fan, you need to pay more attention to what Miska actually posted:

Topping D30Pro Review (Balanced DAC)

thank you Marcos! What converter are you talking about?

www.audiosciencereview.com

D30Pro's noise level in PCM and DSD rates are identical. The noise level differences in different types of tests (high amplitude tone, low amplitude tone, multitone) are caused by the Prism analyzer's configurations.

If a specific DAC chip need to compromise analog output level to maintain DSD signal integrity, then it is already a limitation of that DAC chip, though not necessarily a bad thing in terms of measurement as lowering the output voltage can also reduce distortion, especially when doing high amplitude single tone tests.

In either case, for the RME AKM DAC tests, PCM and DSD Direct have the same analog output level, as pkane explained.

 

[pkane]

I guess the results you showed are completely expected based on the above screenshot I showed?

Nothing surprising for the different noise levels?

Does it matter? The original file was generated and saved as 32-bit PCM, and so contained no analog noise. When playing the same exact file in HQPlayer, I got a 3dB lower SNR when converting to DSD compared to PCM (with the same exact output level). This was measured at the analog output of ADI-2 Pro. That's all that comparison shows.