I think that varying a parameter of a sound continuously, while it is being played is not possible in Mathematica. A workaround is to use an external program. ChucK is a real-time audio programming language that can run many threads ("shreds") concurrently, and allows dynamically adding/removing shreds from the system. We can create shreds that vary parameters from within Mathematica.
Here's a working, continuously adjustable solution based on ChucK:
First, you need to download the chuck binary and put it some place accessible. I put it in ~/bin.
Then I wrote this chuck script, and put it in ~/chuck:
/* snd.ck */
public class MyState {
static int freq;
}
500 => MyState.freq;
SinOsc s => dac;
while (true) {
MyState.freq => s.freq;
50::ms => now;
}
Then I started a chuck host from a terminal using chuck --loop.
Finally, I did this in Mathematica:
(* this will start playing the sound by adding the above defined shred *)
SetDirectory["~/chuck"]
Run["~/bin/chuck + snd.ck"]
(* we'll use this script to adjust the static MyState.freq variable in chuck *)
script = FileNameJoin[{$TemporaryDirectory, "adjust.ck"}]
Manipulate[
Export[script, IntegerString[s] <> " => MyState.freq;", "String"];
Run["~/bin/chuck + " <> script];
s,
{{s, 440}, 200, 1000, 1}
]
Kill chuck from the terminal to stop the sound. Of course there are better ways to do stop/start the sound, without killing chuck, but I was lazy. (You'd need to add/remove shreds that perform a specific task.) This is just a simple example showing how to control ChucK from within Mathematica, using sliders.
