Expression pedal


#1

Just looking to hook up an expression pedal to some basic synth sounds. My idea would be to have the expression pedal trigger for example the vibrato in ‘Basic Poly’ or the modulation in ‘Nori Sampler’.

Any ideas?
(I’m not a programmer)


#2

I’m also interested if there is a simple way this can be explained (both for patches and modules). Basically just how to attach an expression pedal input to an existing “knob” parameter.

I’ve been starting to learn pure data, and tried to look at some patches where an expression pedal controls parameters, but I imagine it would be a while before I can figure this out on my own. Any help much appreciated! I’ll upload the patches when done as I imagine they might be useful to users not (yet) diving into pd. Thanks!


#3

non-orac patches…
simply feed [r exp] into the same input as [r knob1] (or whatever)
this works because knob output is 0…1 and so is expression output.

note… this will have a few quirks if you try to use the knob and pedal at same time.
(you could do something like sum them if you want to combine their input)

orac modules
that’s actually more difficult… as modules are not looking at the knobs, rather parameters.
and the some parameters are ranged (e.g cutoff might be 1hz to 1khz), so you have to scale the exp input by the parameter range.
I think for the future it would perhaps be best if the expression pedal was seen as a modulation source, so could be within the Orac system - that way any user could map it to whatever they want, rather than the module design fixing its mapping.


#4

This was fun to make, fun to use, fun all around!
The exp pedal input is tied to decay, tone, and overall volume at the same time.
https://patchstorage.com/arp-synth-exp/

Thanks to C&G @oweno and @chrisk for making such great and well designed patches like this one. I really take no credit for this as it’s just a simple mod to the C&G Arpeggio Synth patch. Special thanks to @thetechnobear.

If anyone who doesn’t have the pd thing going wants an expression pedal patch mod, I’d be glad to do a few on request. They’re simple, but helping me learn quite a bit. Maybe some will get good use out of this one in the meantime. Enjoy!

edit: @Dominic if you’re still looking to get those two patches ideas hooked up say the word and I’ll give it a go :slight_smile:


#5

cool,

Id be interested to hear your experience of how you use it…
I think an expression pedal / foot switch is a really useful addition to the Organelle, actually any keyboard really :wink: )

as I mentioned when refining pedal support in 3.1, I was thinking of some potential built-in uses

the idea being it would be nice for the pedal to be useful, in some way, without patches explicitly supporting it. (I gave some examples in the above post)

perhaps if we allowed an option to map it to knob1/2/3/4 , this could be interesting.
though it seems really dependent on the patch which knob it would be useful to map too, and doubtfully useful on multi page patches.

I think the more promising ‘general’ uses might be to cover some of the limitations of the organelle keyboard, so perhaps velocity/octave mapping?

as I said, in last post, Orac has quite a few more possibilities because I can there associate it with parameters, in a similar way to midi learn (*)…
hmm, why did i not think of that when doing midi learn? seems so obvious now :wink:
anyway, definitely will do something like that for next orac version…


(*) Orac hack
this actually makes me think, there is quite a simple hack for Orac, which would allow use of the expression pedal for any module!

basically something like (means untested :wink: )

[r exp] -> [* 127] -> [pack 11 $1] -> [midiCC $1 $2( -> [s rackMsgs]

this could be put in a router module…

this maps the expression pedal to midi CC11 (you can map it to something else if you wish),
from there, you can use orac’s midi lean, to learn a parameter… so by implication is then mapped to the expression pedal input.

(note: depending how you update the router, it’ll either be instead of sending exp to the module, or as well as sending exp to the module)


#6

Awesome - this is all great, thanks!

Presently it’s just a way to fade in a simple arpeggio going into the second verse of one of my songs. I should really get around to making/posting recordings, especially since I have some “organelle only” versions. I’ve been expanding my setup with Reface DX and Analog 4 so I’m quickly running out of hands!

After seeing how flexible it is, that it can attach to several parameters at a time, with ability to adjust values per parameter, I’m hoping I’ll get some more unique ideas. I suppose it could work through orac as CC sent to an Analog 4 parameter too!

I really like the idea of having “built in” uses - I do think allowing it to be assignable to a knob could come in handy, but may not be worth it if it’s time consuming and only useful for one page patches (idk how that’d work out for multi-page). I’ll try to think of more possibilities :smiley: