Perfect throughput check

[rec]

1. Take a piece of classical music
2. Play it
3. Record one minute through recs
4. Compare to the original on the same reproduction equipment

This assumes unity gain between steps 1, 2, and 3.

If we use WAV files, the original and the reproduction should be identical!

We could use soundfile as an input to recs instead of sounddevice, so the output should literally be byte-for-byte identical past the header...