The Key object has a root parameter; that's why middle c is 0. You can set 0 to be anything you want, just use s.key.root = #. To set middle C as 60, just do s.key.root = s.key.note2freq(-60). I'm also in favor of standards, but as my notes can cover a range bigger than 0-127, and take fractional values, I'm not sure MIDI is appropriate. I'm unaware of any standards that would fit my requirements, but if someone else is, please let me know. It might be a good idea to set a default root such that 60 = middle C; I'll think about this. But regardless, "0" won't represent the same note everywhere. Another complication is that an octave doesn't always have 12 tones. You can set the tuning for harmonic major/minor (7 tones), or anything else you want. I seem to remember there being some interesting Indian scales that have 15 or 16 notes per octave. One thing this means is that note 0 : note 1 :: note 1 : note 2 doesn't always hold. But since the default is equal temperament, I will consider setting the default root such that those who are used to MIDI will be least surprised. Though that would make the other functionality of Key more surprising, so I'm not sure yet. One of the design goals with this entire system is that physical constraints (your sound card's sample rate and the accuracy and range of IEEE floating-point arithmetic) should be the only constraints keeping you from being as exact as you want to be. In many cases this means that the MIDI standard must be discarded. But being able to communicate with other stuff (including a MIDI-wired brain :-) is also important. At some point I would like to create a module that translates midi key on/off controls to the system I have set up here, but that's nontrivial given the fact that controls (likely) come from a standard keyboard, which has a certain physicality that annoyingly conflicts with the concept of differing numbers of notes per octave. Evan On Mon, Jul 19, 2010 at 12:13 PM, Harry Van Haaren <harryhaaren(a)gmail.com> wrote: