Upsampling DSD, or why use HQP for DSD?

Audio Gear Talk HQ Player
1

Playing around with HQPlayer, so forgive the n00b question.

My DAC (Marantz NA8005) supports DSD128, and I have that set in the settings as the preferred DSD format. HQP upsamples my PCM tracks to DSD128 no problem. However, when I play a DSD64 track, it plays on my DAC at DSD64, not 128.

If HQP is just a passthrough for DSD, why would i want the extra layer of processing in the signal chain? Am I missing something obvious?

2

This is the default, meaning you have “Direct SDM” checked in DSDIFF/DSF Settings dialog. (As a side note maybe I should now rename that dialog to “DSD Settings”…)

With Direct SDM, DSD sources are passed through as-is to keep the direct part in “DirectSD = DSD”.

If you uncheck Direct SDM, you get full equivalent DSP capabilities for DSD sources too. Depending on processing used, it may get heavy… So you get volume control, rate conversions, etc. It is useful for various cases, for example:

  1. If you have future-proof DSD256 content, but don’t have a DSD256 capable DAC yet - so you can play those for example at DSD128. Or you are traveling and carrying only DSD128 capable DAC like Resonessence Labs HERUS and want to listen DSD256 content.
  2. If your DAC performs better at DSD128 than DSD64 due to analog filters, etc
  3. If you want to use HQPlayer’s volume control
  4. If you want to use digital room correction, or run digital cross-over filters
  5. Plus bunch of multi-channel use cases, but those don’t work yet with Roon because Roon is stereo-only at the moment

So overall, there is no simple answer, you can try and listen which way you get better sound.

2 Likes
3

Thanks for the quick reply! Yes, please rename that menu item. i assumed that because the bitstream was coming in from Roon, those settings didn’t apply (I figured that was for DSF files played directly from HQP).

I’ll keep playing.

4

Good idea. I think it’s less confusing for new users … and it’s shorter.

5

And if it’s about general DSD playback settings, it shouldn’t be in the File menu, it should be in the application menu with Preferences.

6

+1. Right under Preferences…, in the same “group.”

7

Any idea of processor load when upsampling dsd 64 files to dsd 256 or 512? How does it compare to converting PCM to DSD 256?

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Thanks Jussi, I just got a DSD capable dac and I now upsample everything to 2x DSD, then I played a DSD signal through it and it played 1xDSD, I wondered why. Now I know, uncheck directDSD. I agree rename it DSD settings.

9

Processor load for the settings I have (which are really close to default) seems pretty low on my MacBookPro when converting DSD64 to DSD128. Doesn’t seem to be anywhere close to taxing the machine at all. Same goes for PCM to DSD128.

-mike

10

Thanks. I was wondering because converting PCM to DSD 256 runs the quad core i5 in my iMac at about 50%.

11

That’s a Mac peculiarity. What appears as “Preferences” on Mac in different place is actually in File menu on all platforms and called “Settings”, but the toolkit automagically moves it to Mac-style place and renames it…

13

Sigh, I just found this in the Qt 5.5 documentation:

“Additionally, users expect certain conventions to be respected, for example the application menu should contain About, Preferences, Quit, and so on. Qt handles these conventions, although it does not provide a means of interacting directly with the application menu.”

Sigh.