I have an RPi4 + Kali + Piano 2.1 which I have had set to Dual Mono in the DSP settings and which combined with Volumio has been perfect for some time.
After a recent update the DSP Settings options changed and I can no longer select Dual Mono.
If I use alsamixer to set Dual-Mono (and reboot) with connections to Left and SubRight I only get the Left channel (nothing from either Right or SubRight).
two of my friends have the same problem, last week I also tried to get a new system up and running for someone, but I also did not manage to get dual mono working, in my own setup I have exactly the same problem as yours , in one way or another it just doesn’t make sense and it is always different with the same devices / setup.
so something goes wrong somewhere, it is strange that the same setup always has different results.
This appears to be a regression of the driver on newer kernels.
I would suggest to report to Allo to see if they can suggest a solution to us, we will then gladly implement it
Since kernel 5.X was introducing lot of bugs the last time we tried it, we need to make sure all other DACs and all other functions work perfectly before updating the kernel.
We can do an experimental version with latest kernel and post it here and you will tell us if all works fine
I don’t know how long it will take with the experimental version but I have decided not to wait for that and have now purchased an allo boss 1.2 dac I have too many problems with shifting the audio left and right with the allo piano 2.1.
yeah, this issue is pretty old and really, it should be fixed by now !! I have a piano2.1 + Kali which was the top recommandation a few years ago and which is a great combo but cannot use it since version 2.6x … come on, please !
maybe you should just select headphones under playback option / output device then reboot and again select the piano 2.1 and reboot without touching the setting … maybe it helps.
it is and remains a strange case that piano 2.1 with kali reclocker