I am aware of PDL :-) I don't actually do any audio processing in perl itself (though the API allows it) - the plugins written in C take care of all the audio data (except for a few conversions to Audio::Play, but even that is mostly C code).

The perl based plugins only do "control channels", that is - they generate only 1 float per channel each "tick" (with ticks once every 40 .. 200 samples). PDL can't really help with the control data, I think, since you're not acting on arrays of numbers, only single values.

I do see there's now a PDL::Audio module on CPAN. That wasn't there when I started this (2 years ago). I'll have to check it out.