I can confirm that lastest version of sunvox use 100 % cpu then crashes after a few seconds.

terminal output is multiples times:

ALSA snd_pcm_writei error: Broken pipe
ALSA EPIPE (underrun)

and when it crashes:

ALSA Can't recovery from underrun, prepare failed: Input/output error
sunvox: pcm_pulse.c:361: pulse_write: Assertion `pcm->stream' failed.
Aborted

You might want to download an older version (sorry I don't have it, try playing with the download url or search the net) and contact the author about the issue.