@ricky said:

Do you think it would be possible to detect the oscillation/beating interaction between two tones using an object like [helmholtz~]? - I would really like to develop a patch that did this so I could use the oscillation rate to control different processes.

e.g. An interval of a minor second would produce fast oscillations which could be used to control the rate of an oscillator.

Nice idea! I think for measuring beating, you will need a pitch tracker that works below the threshold of human pitch perception.

Excellent and loads of fun

If you think of the shapes of a slow (low pitch) sine oscillation and a fast (high pitch) sine, the fast sine has steeper slopes. Now all signals can be recreated by sinewaves (fourier transform.) So any signal that has a fast change of value if you think in terms of frequencies has high frequencies in. Using a LP filter gets rid of the high frequencies and so smooths the signal out.

Not meaning to troll but, I just plug my audio interface directly into my amp and it sounds like magic. Maybe I'm lucky with the preamp section of my amp or maybe I'm putting some kind of undue strain on it that will only be revealed after a few years of abuse.
I don't really know too much about the issues involved and am speaking from a position of ignorance so take what I say with a pinch of salt, however, I do paid gigs using this setup.
My gut feeling is that most guitar amps are designed to put up with a lot of abuse and plugging an audio interface into it (with the output level suitably low) is hardly a major problem.

You need to send a message to a line object going into the osc~. Like this:

[60, 960 1000( - jump to 60 then interpolate to 960 in 1000ms
|
[line]
|
[osc~]