Thanks for the reply! I feared it might be because of these technical audio limitations.
I'm trying to use this for an mp3 player, where I preprocess an audio file into the amplitudes of many speakers (at different pitches and sounds), playing a new packet every update tick.
What might work is ...

I built a speaker that plays an instrument sound for 1 tick every 20 ticks.
The timing of the heard sounds seem a bit random. Some sounds are skipped, and the durations of a note is between 10ms to 25ms, so from half a tick to 1.5 ticks.
I would expect for each sound to play for 1000/60 = 16.6 ...