Please kindly explain, page-31

Yep, no, they know not to do this, so that's why it's a worry.

There are three things which are important for mission success of the audio output.

a) Frequency bandwidth
b) Volume
c) Sound quality

Don't infer anything from the recording, you can't. It's too obscure. Frustrating or a red flag? You choose. I hate being any more critical.

for a) Frequency bandwidth. Seems to be promising but requires volume to push all frequencies.

for b) Volume, the fan could be inaudible and at a distance of 10m, and the chip could be right up next to the mic, with a sensitive mic and high gain you can get chip to be recorded quite loud, but this would make a previously inaudible fan quite loud too, like seems to be in the recording.

for c) Sound quality. Obscured by fan. The organ is an instrument that already has a timbre constructed of simple tonal elements with only select overtones and harmonics present, adding to this, the recording was constructed from a single musical scale with limited variation, and only a limited of that scale was played. What I'm saying is that even if it wasn't obscured by the fan, the sound chosen was not sufficient test, and what was produced could be produced by limited array of lo-fi monophonic emitters.