I recently got an RME DAC and was curious about the bit perfect test. Though I couldn’t figure out how to get it to run.
The only DSP I had enabled was volume normalization, and the signal path showed it was applying 0.0db change. But it was converting 16 bit files to 64 bit and then back to 32bit which is the max input bitdepth.
This makes sense that the 16 and 24 bit tests would fail, as they are being passed in as 32 bit files. But why are the 32bit files failing?
For some reason Roon takes a 32 bit wav file, converts it to 64 bits, does nothing and then converts it back to 32 bits and this is mangling the test data?
When turning off normalization the tests all pass fine.
The only mention I could find of this on here was related to a bug in an old firmware of the DAC.
Any DSP applied to audio files makes sending them no longer bit-perfect, so it’s normal for the RME test to fail (the test is for bit-perfect).
I’d understand if DSP was being applied, which is why I understand the 16/24 bit tests fail. But shouldn’t the 32->64bit and 64bit->32bit be a lossless process considering no volume change was actually applied.
Roon is still performing bit-depth expansion and dithering back down to 32bit when Volume Leveling is enabled.
Are you sure that volume leveling +0.0dB is meaning 0dB, and it is not meaning +0.0001 dB?
Even if it means 0dB, Roon still does upsampling and downsampling, so the file is corrupted and not bit-perfect.
Also, signal path does not indicate “bit-perfect”, but “enhanced”.
I guess you could do a check to see if 0 normalisation is taking place you could skip the double conversation but I appreciate its relatively rare to have tracks that need no change when normalisation is enabled.