This solved it! Thanks a lot!

Hello!
I'm fairly new to Pure Data, but thanks to several tutorials I managed to somehow get close to what I want to achieve:
I want to change the pitch of an audio signal live, by pressing the keys on my midi-keyboard. This I have managed to do, but now I also want to be able to press several keyboard-keys at once in order to create a chord - for instance pitch-shift the audio signal to a C and E and a G at the same time.

I tried to combine this Pitchshifter:
https://github.com/pure-data/pure-data/blob/master/doc/3.audio.examples/G09.pitchshift.pd

With the Poly-setup discussed here:
https://forum.pdpatchrepo.info/topic/5311/polyphonic-voice-management-using-poly

The pitchshifter works by multiplying or dividing the frequencies of the audio signal.
If I want to be able to produce 4 notes at the same time, my guess is that I need to have 4 different pitchshifter-setups that respectively are connected to the nodes of the route-output.

The problem with this is, that if I for instance only would play one note - one voice of the midi keyboard so to say - one pitchshifter would play my desired note, but the 3 others would still play the untransposed audio signal.

Is there a way to check how many keyboard-keys are being pressed or which voices are being active, and then accordingly mute the pitchshifters?

Polyphonic Pitchshifter.pd

Thankful for any help!
David