Something isn’t right there. Here is what I see.
With Enable Core Decoder set to NO:
With Enable Core Decoder set to YES:
Best I can tell the signal path looks the same, and it’s showing Full Decoder in both cases. Musically, I strongly prefer the core decoder set to no. The life seems to go out of the music in the case where Enable Core Decoder is set to Yes.
If I have DSP in the chain there is a big difference in signal path. I didn’t get screen shots when I did this but I wrote it down.
With enable core decoder set to NO:
Source>MQA Authetication>Bit Conversion> Convolution Filter>Bit Conversion>MSB Analog DAC>MQA Full Decoder
With enable core decoder set to YES:
Source> MQA Authetication>MQA Core Decoder>Preserve MQA Signaling>Bit Conversion> Convolution Filter>Bit Conversion with Restore>MSB Analog DAC>MSB Renderer>Output
It is quite interesting that Roon chooses to process the MQA signal differently when the core decoder is ON (sending a partially unfolded signal), versus when it is OFF (sending the whole thing intact to the DAC. I have to say here that I found this confusing musically. I ended up turning the DSP off because it sounded ‘worse’ going through DSP and MQA vs MQA alone. There is probably some physics here I should understand, but I don’t want to deal with it.