Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/music-synthesizer-for-android/commits/commit/a762514187e4ebbe4ea510c58a23b6b16aba815f/lab
You should set ROOT_URL correctly, otherwise the web may not work correctly.
The sawtest.py script generates audio samples for various filter
implementations (including matrix exponential and TPT) with various
input signals and settings. It should be useful for comparing the
quality of the various implementations, even though it's pretty slow.