TempoClock tempo fading

Questions
1

Hi!

Does anyone have ideas for fading changes to the tempo of the default TempoClock?

Ideally I would like to have a smooth transition a bit like BeaconClock from the brilliant Utopia package has but with vanilla TempoClock.

Here is my attempt at doing so, but I wonder what other people do ?

(
// Tempo changer
Tdef(\tempo, {

	// Time between tempo adjustments
	var timeGrain = 0.01;

	// Fade time
	var fTime = 16;

	// Current tempo
	var ogTemp = TempoClock.default.tempo;

	// Target tempo
	var newTemp = 0.5;

	// Envelope used for the fading
	var env = Pseg([ogTemp, newTemp], fTime, \exp).asStream;

	var val = 0;

	// Do the tempo change
	loop{
		timeGrain.wait;

		val = env.next;

		if(val.isNil, { 
			Tdef(\tempo).stop 
		}, {
			TempoClock.default.tempo = val;
		})
	}
}).play;
)
2

I use this for tempo changes:

https://swiki.hfbk-hamburg.de/MusicTechnology/763

3

That just came up in a parallel thread, I’d do it similarily with a clock setter pattern:

4

Mads, I just realised, there’s a problem with your definition, you’re setting the same clock on which the Tdef is running and which determines the fade, so the wait times are changed also. You need two different clocks, but of course a Tdef can accomplish this as well as a Pbind.

5

LOL I had totally forgotten about this. Thanks for pointing out.

As you say, using a Pbind is also a good idea. Maybe something like this is a lot simpler and more flexible (with the same problem of running on the same TempoClock)

Pbind(
	\dur, 4,
	\tempo, Pwhite(0.1,2.0), 
	\play, Pfunc({|ev| 
		var t = ev[\tempo]; 
		"Tempo is now %".format(t).postln;
		TempoClock.default.tempo = t 
	})
).play
6

See my second example here: