I have an interesting problem where I get loud ‘static’ noise when trying to play any audio back through RoonBridge. I don’t know if that’s the right word to describe it - the noise is like it is getting the raw digital stream instead of analogue, so a bit pink noisy, square-y - that kind of noise. It’s always at full volume.
Weirdly though infrequently it has worked fine - maybe once in every 20 or so times. Also once or twice it also played the correct audio in the background behind the noise!
RoonBridge is running on a base Debian 11.5 net-install with just ALSA and RoonBridge installed as per dependencies. check.sh says it has everything it needs, and obviously it loads fine.
The DAC/soundcard is a Mixars Quattro. A DJ mixer with 2 x USB soundcards in at 24/48 and 16 channels.
Playing any audio from Debian itself is perfect (via ALSA) - there is no static noise at all. I can run other software like shairport-sync and that works fine also - which also uses ALSA.
If I switch to Windows or macOS with the soundcard it all works perfectly also. Even Windows on this specific machine works perfectly. So it is a specific issue with Linux RoonBridge and this soundcard.
I suspect that it is because, as I understand it, RoonBridge is bypassing ALSA config in some fashion and addressing the device directly - so ALSA at the OS level is negotiating capability with the card properly and working, whereas whatever RoonBridge is doing is not.
The card itself is listed as class-compliant. There are no drivers. It has 16 outputs and no volume control (digitally).
I’ve tried a lot of things, especially obvious things - but I am now at a bit of a loss - so posting here to see if anyone can advise on other things to try? I feel a bit hamstrung as if RoonBridge is bypassing the ALSA settings of the host (and specifically the asound.conf) then I am limited in what I can do by what is configurable in Roon itself.
- Reducing / changing the max bits per sample rate does not change.
- Max sample rate is not exposed as it only support 48 khz.
- Changing the Volume Control does not fix it - and interestingly even with DSP volume set the noise is always at 100%.
- Setting to max volume does not fix it. (I saw somewhere that this might occur on volume change, but that is not the case here.)
I am fairly competent with Linux/Debian so happy to take any tips!
Please help as for now I have gone to shairport-sync but still using Roon to send audio.