jitter_pvoc_3D by Luke Dubois / scaling of magnitude data

t's icon

Hi,

Below is a patch from Jitter examples by Luke Dubois called jitter_pvoc_3D. What I can't understand is the "make_FFT_viewable" subpatch so I have few questions about it:

1. Patcher "makemap" inside "make_FFT_viewable" are the instructions how to scale the magnitude I suppose but I just can't understand it. What is the logic behind this mapping? I hope this can be explained to someone who doesn't know the maths behind the FFT...

2. What is the function of interpbits attribute in jit.repos? Why @interpbits 8?

3. Why "qmetro 2"?

Max Patch
Copy patch and select New From Clipboard in Max.

Thanks a lot!