So I just received a Pi4B 4GB, DAC+ DSP board. Hooked up the HifiBerryOS (20200908) image, added dtoverlay=hifiberry-dacplusdsp.dtbo to config.txt, loaded the "DAC+ DSP Universal V10" DSP programme. Hooked up a DAC via optical out, and at least I get some music via Airplay and Spotify Connect. So far so good.
Now in Sound -> Channels -> Advanced I can see 4 channels. However none of the sliders or buttons seem to do anything. I would expect to be able to change the volume of the individual channels.. but nothing.
In Sound -> Parametric Equalizer -> Speaker Equalizer, I can group channels and define filters, but they don't seem to have any effect.. Nothing..
Strangely Sound -> Parametric Equalizer -> Sound Design does work! Some EQ'ing there does seem to change the sound in an expected manor.
So either I'm expecting things I should not, or some settings might be wrong somewhere..
Tried # /opt/hifiberry/bin/reconfigure-players
DAC+ DSP 1
Nothing changed, exiting...
So looks like it did find the DSP. Also tried rebooting the thing, with no avail..