Expression Pedals & Boss RC 300


Howdy Gang

I am considering picking up some kind of footswitch / expression pedal / looper combo. In my research I came across the RC 300–which is a 3 track looper + expression pedal.

Seems a likely good companion to the organelle… Has anyone used the expression pedal component in this unit with success? I know mileage may vary per patch, but I’m curious.

And in general, is there a list (or can people offer what they use) of expression pedals that work? I’d love to get some swells going, either of volume if not knob/fx behiavior.

Thanks everyone!


I recently got the same itch and picked up the basic little single Ditto.

Does the Organelle even do expression via the footswitch? I’ve only ever felt it work as a hard on/off type and the little piano pedal I use has no travel so I just may not have picked up on it on any patch that does use it.

If there is expressive patches I may need to get a proper expressive pedal then!


According to the manual it accepts expression input but never tried it.


expression pedal - yes works, kind of :wink:

so my Yamaha FC5 sustain (not expression) pedal works fine , as on/off as expected.

however, my Yamaha FC7 expression pedal has two minor issues:

  • its a TRS (stereo jack) which is common for expression pedals, and this does NOT work with the Organelle, however , if I take the right only side of the jack (so mono) it works.
  • it appears to be reversed to what is expected, and slightly compressed ranged
    i.e. full down is close to zero, full up is about ~100 , so not 127

id be interested to hear from @oweno on this, as honestly i dont know much about expression pedals, but thought the FC7 is pretty common/standard.
(I admit, i was kind of surprised to see that the FC7 was stereo , I assumed it would be mono)

Im assuming the pedal input on the organelle is mono, but confused why this is the case if the FC7 is stereo?

Reversal, is this something that should be compensated/allowed for in mother.pd?

so yeah, it kind of works, but not sure if its as intended/needs some tweaking.

(hey, i admit the FC7 is almost the size of the Organelle, so perhaps not the expected pedal… but what I have to hand :wink: )

as to patches… given ive not seen any comments about the above before=
(im guessing few have tried… or my pedal is different/exceptional… anyone saying their expr pedal is different?)

though it makes me wonder…
I think its cool for patches to be able to code for pedals directly, but if few users (and patch developers) have them , then perhaps we should consider some ‘standard behaviour’ for them?


  • sustain pedals could sustain notes without the patch having to do anything (i.e. we mess with r notes)
  • expression pedals could be ‘mapped’ to knob 1-4, volume , again so patches dont have to do anything
    (there was also talk of using switch pedals as patch switching)

of course this could be ‘optional’ behaviour which a patch could opt-out of, but at least then those with pedals get a reasonable experience regardless of the hardware/inclinations of the patch developer…

(sorry if this is considered OT, but given the question here is essential will the Expression pedal work on the RC300, I think its relevant ?!)

EDIT: ok, so a bit of search on the internet, looks like the Yamaha pedals are reversed polarity, not noticed before, as other hardware works fine… anyway, Im not sure if this is contributing to the issue … certainly might explain the requirement for mono adapter… I dont have necessary cables to completely switch polarity, and then insert back as stereo… to see if it completely works.
(I doubt this can be handle in software, as i think its part of the microcontroller software which cant be reprogrammed)
Id still be interested to hear from @oweno if the pedal input is mono or stereo though.


I have tried with a Roland DP-10 (this one has a switch can work both as on/off or continuous)
Lately I’m headless, but recall looking at mother.pd as slider works as supposed!
This also with a Roland EV-5 (this one has a knob to adjust range)

@thetechnobear continuous pedals are TRS

from the manual

NOTE: Organelle presumes that any sustain/damper pedal used has a “normally closed position” (negative polarity).
NOTE: If an expression pedal is connected, your patch should receive a continuous range of values. In our experience, various expression pedal models and settings tend to deliver different ranges of values. This can be addressed at the patch level.


That amazing feeling when your organelle does a new thing :smiley:


@keymanpal thanks, yeah, after a bit of searching i noticed Yamahas pedals seem a bit different… just some synths seem to deal with it ok, some not :wink:
any how, its a bit big to use with the Organelle, so perhaps i can find something smaller/lighter that would be more suited to the Organelle… I think interesting given no lack of velocity/limited knobs etc.


@thetechnobear All this pedals are simply a linear knob either 10K or 500K ohm.
Some more info:


this one covers a lot of ground too…


Just the conversation I was hoping for! More interested in the expression pedal than the looper, just thought the Boss might be a best of both worlds type of combo.

What’s the takeaway here? What is the spec to look for in an expression pedal?

And how would one map such a pedal as if it were a knob in a PD patch? Is there a good example patch out there for this?


I don’t have a RC 300 and was holding for if someone use one, but the way I see it is a sophisticated “floor-recorder-computer” and a overkill and more headache just to get the signal from that pedal to the organelle (maybe its even just connected for “inside” RC 300 duties and NOT possible) if you just want an expression pedal for an added continuous control…


Makes sense! Looks like I could start on the cheap with an m-audio exp or a Roland ev 5, would you agree?


yes! on the expression pedal (and in the meantime take advantage of it in patches)
But loopers are great fun! don’t take me wrong.


Could anyone point me to an existing patch that ‘attaches’ an expression pedal to function (as one would a knob)?

I also saw this old thread from about a year ago that makes it seem that mother.pd needs to be modded to get the M-audio Exp to work. That seems scary. Paging @jhindsight, are you still rocking with the pedal a year later?

Would the Roland EV-5 work without that type of mod? This is all very new to me, sorry for all the questions.


it’s quite easy to attach a FW to a function it just matters what you want to modulate really. i found a bunch of the pedals had fluctuating voltage and i know i included it on a few but it’s disabled I’ll look


Hi @healthylives, yes I’m still using it. As other people have mentioned, not all expression pedals give the same output and I found I had to add a simple multiplication in my mother patch to allow my pedal to work as a trigger.

In terms of adding foot switch support into a patch it’s fairly easy. There is a receive object for both footswitch (r fs) and expression input (r exp). Knobs and footswitches give values between 0-1 so you just decide what those values do in your patch.

I could probably knock together a simple pedal calibrator patch but it would mean replacing the mother patch with my modified version.


I think this would be better done in the mother host…
a bit like midi settings, you’d set it up once, then all patches would seem ‘r exp’ the same.

again something to deal with in mother host… probably will a simple low pass filter.
the issue is, if we have constant fluctuation/oscillation , this creates unnecessary osc messages which can affect the responsiveness of the patch, and also additional cpu load.

my general thinking is… mother host should preset and ‘idealised view’ if the hardware, such that the patching code can be simple, so as not to burden patch developers unnecessarily.

(of course, smoothing should be able to be turned off in mother host for ‘special cases’ where you want the noise :wink: )


Agree it should be in the mother host. I did mention it in my original post and oweno replied so maybe it’s on their radar for the future.