I wonder how it sounds if you map the primes straight onto Hz instead of piano scales.

It won't be a musical scale if mapped directly to Hz (maybe sine wave mapping?).

For example, prime 2 → 2 Hz (inaudible), 101 → 101 Hz (deep bass), 1009 → ~1 kHz (bright tone).

Right now the app just maps primes to MIDI notes so they sit nicely on a piano.