Etc.audio_in

[oweno]

There is a little more info about the sampling rate and 100 point array here:

Eyesy sampling frequency

The 100 point audio_in array is filled at 36.75 Hz (this is 11025 Hz sample rate / 300, I can’t remember the reasoning exactly, that part of the code is here) 36.75 * 8 = 294 Hz, so what you are seeing makes sense. The audio sample rate is fixed at 11025 Hz, this is dictated by the hardware and independent of frame rate.

Basically it is updated 36.75 times a second in the background. Position 99 would be the most recent.

To check for threshold you could do a for loop, it might not slow down too much. But there is also the etc.audio_trig flag that gets set when audio exceeds a threshold, might be useful. The threshold is hard coded at around 80% full volume.