PD has a object called fiddle~. You can run the mic into this and (among other things) gives you the midi note which correspond to keys on a keyboard. Or you can run to output into mtof if oyu preffer to see Hz. pd.iem.at Here is a layout. [adc~] | [fiddle~] | [ (midi note) > | [mtof] | [ (frequency in Hz) > Hope this helps! -thewade