[PD] Crossfade between 2 rj lib save states?

Andy Farnell padawan12 at obiwannabe.co.uk
Tue May 14 10:28:18 CEST 2013


> I'm not looking to crossfade audio at the end. This will be a midi note 
> and CC generating patch for my synths and samplers to record and to play 
> live with.

So this is a kind of compositional technique, "continuous parameter space
transition", or a slippy synth or whatever you want to call it and there's 
a couple of tricks you can use to turn any set of synths toward this;

1) Assume you have a state saving and loading system that returns
lists like {1.0 0.4 0.01 0.333 0.0}

2) We have N of these that represent continuously variable parameter 
states P throughout a composition and we want the sound to slowly morph 
through them all, reaching a new state every T seconds

4) These cannot be parameters for other time variant parameters E that
are only read at event boundaries, like envelope ADSR values.

Solution:

Break up the list into new list pairs where every other value is the
morph time T. With a morph time of 3.0 seconds we get 
 {1.0 3.0} {0.4 3.0} {0.01 3.0} {0.333 3.0} {0.0 3.0}

Send these to [line] or [line~] objects 

If you have events like notes also running and retriggering envelopes
then arrange the parameter data with them all at the head of the list
 {E E E E P P P P P}

Use list split to pull those off, store them in a list and resend them  on 
each note event. Send the remainder to the bank of [line] objects, once only.

This is such a compo

http://obiwannabe.co.uk/sounds/sparkle.mp3

There are no "events" in this, just one long single note.
The first bit that sounds like chords shows off the potential
for more standard composition. Actually the sounds are
'timbres' of the note, where the harmonics are carefully set up
to give a chord like structure. I picked a bunch that sound nice
together and then found a set of quick (20ms) transitions along
a  path between them. The second movement just picks five or six 
random coordinates in the space and moves between them slowly to 
show the kind of crazy electroacoustic sort of sounds such a 
synthesiser can make. 





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