Beep

I have this little patch that I found within the elastic~ help file. It basically converts MIDI note numbers into a ratio for elastic~ playback. Apart from it being a really useful patch for people to have (it would work just as well with groove~ as elastic~) I am putting it up here to get to the bottom of the maths embodied in the expr object. Can anyone shed any light on it for me? I am no mathematician but I hate not understanding things, just how does expr ((440. * exp(.057762265 * $f1))* 0.002273) convert MIDI numbers into a ratio like that?! What do the numbers represent? Many thanks...

really-useful-patch-for-converting-midi-note-numbers-to-a-ratio-for-groove

You could write the expression like this, and it gains a little in terms of precision.

I personally would use [expr pow(2.,(($f1-48.)/12.))] so you don't have to stare at those ugly decimals.

How would it be the other way around? I mean, if we want to translate a frequency change into a midi transposition?

really useful patch for converting MIDI note numbers to a ratio for groove~