Hello,
         My name is Daniel. I'm currently working on a patch for an investigation on the effects of harmonics on human health. I'm new in PD and would like to ask if the following two patches are possible:
1)       First I want the user (test participant) to be able to play a sample and choose a particular fundamental frequency for that sound. Then the user should be able through certain keys from the computer keyboard to filter that sound and let the fundamental plus a certain harmonic be heard. I would need to assign 15 different keys to the first 15 harmonics.
      So I suppose what I need is like a sampler that works like an instrument, I would use probably a cello sample. When I press a key, the sample should start to play and keep playing as long as I keep pressing the key. And it should stop when I release the key.
2) A second approach is to let the test participant sing a fundamental note and through pressing certain keys let him/her hear his/her voice filtered with a particular harmonic amplified. That should happen live, as he/she sings. It's a kind of artificial overtone singing.

I'm currently following the tutorial of Kreidler (pd-tutorial.com) and it seems pretty complicated. I would really aprecciate your help, specially regarding how to make a key play a note or activate a filter.

Best regards,
Daniel Salva