This problem only occurs when samples very close to min/max limits is played. Sounds like integer overflows to the other side. My sample data is correct (not overflowing itself), but apparently ALSA has stricter limits.

I'm using device hw:Intel, so ALSA shouldn't be doing any sample format conversions. Thus I suspect that this might be a fault (a feature) of the hardware itself.

Can anyone confirm this?

Playing in 16 bit mode there is no problem and even -32768 seems to be playing properly.