Hello, so I don’t think this is inherently related to Patchbox OS but maybe someone can help me anyway. I’m using a Raspberry Pi 3B+ with Patchbox, no external sound card*, and a MIDI keyboard for input.
(*I have one I could test it with but I really want to see what I can squeeze out of the RPi first, and I’ve read people have been able to get good sound with amsynth without a sound card so I feel like the issue must be somewhere else)
I got Fluidsynth working with good quality sound and no audible latency, now I’m trying to do the same with amsynth but I’m getting HORRIBLE distortion, no matter what sample size/period/buffer combo I try. To get Fluidsynth working nicely I used: “jackd -R -d alsa -r 44100 -p 512 -n 3 -d hw:0,0”
In the amsynth settings I tried every audio driver:
- ALSA: horrible distortion
- JACK: different sounding but just as horrible distortion
- ALSA-MMAP: clean sound, but horrible latency
I quickly tested a random plugin in Carla and the same issue appears to be there, so now I’m not sure why Fluidsynth has no issue but amsynth and Carla are struggling. Any ideas (or directing me where I should be posting this instead…) would be appreciated 
Edit: Came across this… https://github.com/jackaudio/jack2/issues/809
I think I saw 8 outputs in Carla’s patchbay but I didn’t pay attention to it. I already unplugged everything, but I’ll test later if this could be the problem.