As promised, here's the frequency analysis of the original ZeroCool firmware running on the Rev B board. As I have been toiling away at finding a new work family, the board has not yet been flashed with the latest firmware. Developed using the breadboarded circuit as outlined in previous project logs, the latest version of the ZeroCool firmware uses a subsonic frequency that avoids any perceptible noise.
For now, I will leave you with this ear-tormenting graph. Let this be a lesson to avoid audible frequency ranges when pushing a PWM through anything that might act as a transducer, such as a mini cooling fan.