Touche

In a context of audio sampling, i'm looking to map an information of pitch (be it MIDI or a frequency, but conversions are easy) into ratios, to use controlling audio playback speed.

the whole range would be centered on midinote 60 for a ratio of 1. (normal playback speed); an octave above (note 72) should correspond to a ratio of 2. and an octave below to 0.5

so, how to map the whole pitch range to ratios relating to midinote 60 . My maths knowledge is quite poor.

this should be a very common thing to do and seemed trivial to me but I got stuck. neither in MSP nor Max tutorials I could find an answer. Peter Elseas pitch tutorial got me on the track but Im still not quite there.

In a context of audio sampling, i'm looking to map an information of pitch (be it MIDI or a frequency, but conversions are easy) into ratios, to use controlling audio playback speed. 

pitchtoratio

Take the pitch through mtof and divide the result by the mtof of 60 (your reference).

here you go, two objects is all you need:

my math is indeed quite poor, and I thank you a lot.

PitchToRatio