On Wed, Oct 9, 2019 at 3:21 PM <nik@parkellipsen.de> wrote:

The samplerate was 44100, period size 1024. Going up to 2048 made it
worse.

Started with:

jackd -P98 -dalsa -dhw:2 -p1024 -n8 -r44100
scsynth -u 57110 -z 256 -i 0 -o 8 -m 262144

try running at 48kHz with 3 periods and see if that helps.