NAD M33 renderer at 48kHz - but Roon unfolded to 96kHz

Ubuntu Srever Core
Ryzen 4350G

Ethernet network
Both CORE and NAD M33 connected to router.

I am a bit confused by my signal chain:

It looks like Roon is doing an unfold to apply PEQ processing, however, when the NAD renders the file it is showing just 48kHz.

Is this correct?
The source file showing as the below:

What’s happening here? Why is Roon unfolding to 96kHz if the file is only 48kHz?

NAD M33 is set up as Decoder + Renderer and the setting for the Roon Core Decoder MQA is set to ON.

This is how MQA works with Roon.

You’ve told Roon that your device can both Decode and Render MQA. You’d also told Roon it can do the first decode with the “Enabled Roon Core Deocder”. Understand that MQA decoding always results in a fake 96k bitrate, regardless of Roon or the endpoint doing the decoding.

Because you have applied PEQ, Roon is doing the decode, preserving the MQA control bits, applying the PEQ process, and then laying the MQA control bits back into the stream so the endpoint can render it.

If you don’t have anything that requires Roon to do the decoding (such as your PEQ DSP setting), when Decoder + Renderer is selected, Roon will pass the raw bitstream to the endpoint unchanged. This will be a 48k “transport”, that the endpoint then decodes into the fake 96k bitstream.

Thus, you get the best of both worlds. Let the endpoint do the decoding when you aren’t changing anything in Roon, or let Roon do the decoding and “preserve” the MQA control bits if you do.

But no matter what, MQA is a 48k input stream that gets decoded to a fake 96k stream (and then rendered to even faker higher-resolutions by the endpoint if the control bits say so).


Thanks, makes sense.

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