LP filter : linking cut off frequency with note

[emmanuel63]

Hello,

I am building a simple synth with a low pass filter. I don't know what is the rule to link to frequency of a played note with the cut off frequency of the filter.
I tried something very simple :

myLPfilter.frequency(note_frequency * FC_ratio);

With a FC_ratio range from 0.5 to 200, I have an acceptable result, but I doubt it is so simple...

Emmanuel

[UHF]

This is also known as keyboard tracking, it's discussed from #11 here: https://forum.pjrc.com/threads/67218...esonance-issue