ForumsHardware ← Call for input: Soundplane to CV module

This year it seems desirable and possible for Madrona Labs to make a Soundplane to CV device. This would be primarily a Eurorack module, but the circuit could also be built into its own enclosure for use with vintage synths etc.

Normally I do most of my design work in private, and only announce a product when it's pretty much done. But we (Brian and I) are going to change it up this time. Because neither of us is that deeply into the Eurorack world, it makes sense to solicit input early on in the process this time. This is going to be a utility device (though hopefully an elegant one) — so before we get too far along, let's make sure it will be useful to you!

The basic idea

USB jack for powering the Soundplane. Module puts out CV / gates / mod outputs for individual touches. Like the Soundplane app, a zone map decides how the Soundplane surface is divided up into notes and what those notes are. You can switch between zone maps, and the name of the current one should be displayed somehow. Aside from this, visual feedback will be at least an LED per Z value. To keep costs low, probably nothing too graphical or fancy.

We're looking for input on things like:

How many voices?

Each voice of touch output will probably have 4 outputs for pitch, x, y and z. Setting up many voices on a modular is not the way most people use them, so I'm guessing that two voices of output will take care of 90% of what people want. We would probably add an expander module for more voices.

Any interesting modes?

A switch that changes z (pressure) into a strict on/off gate might be useful. Any other things like this?


individual voice groups vertical or horizontal? voice outputs at bottom or top? I'm thinking top, because a USB jack on the bottom will go to the Soundplane.


The module will need roughly 250mA at 5v to power the Soundplane. Brian will correct me if I'm wrong. Then there's whatever computing and display the module needs to do, and the outputs. Do we need our own power supply, or a list of compatible Euro power supplies that we can point people to? Any choices in connectivity to make here?

Finally, we're still looking for a great name…

any updates on this?

I will be very excited to share news when there is any. For the time being I have to work on software.

In case you missed Velocity or the followup report, here's what was shown:


Basic touch detection code has started working on the embedded ARM platform, and things look promising.

time passes by so quickly, soon it's been 5 years since this thread was started.
any news on this front? i know it must be annoying to get/answer this question year after year but i now wonder if this will ever happen ... i still love my soundplane dearly and really really really would love to be able to use it without a computer.

Yes, we will definitely finish the module. We made some real progress this year and I'm excited to get back to this and the Soundplane Model B when I can.

What I'm working on now is the next plugin (Sumu). This should provide the income to get back to hardware development this year.

I'm sorry that I set up unrealistic expectations about the date. Because I support the company by making software, hardware progress is going to be slower than the pace you might be used to from most companies. My boundless optimism about ship dates is a useful kind of coping strategy for me, sometimes. I am learning not to say these things out loud until we are much closer to finishing a project.

thanks very much for your reply randy!

I'm eager for this as well :)

@timoka what ive been doing whilst waiting is to get the soundplane working on a Bela Salt - it's a bit expensive,
BUT I can also get the same software working on the Bela Pepper albeit with a reduced voltage range (0-5v, rather than 0-10v) - but its a cheap DIY option!

the disadvantage compared to Randy's module, is they only have 8 outputs (salt has an additional 4 gate outputs), so reduce number of touches or axis.

but, whats nice is... once the madrone labs Soundplane Module becomes available, I will be able to re-program the Belas to do something different :)

another interesting side of using Bela is I've been able to explore how I want to use the soundplane with modular - I do enjoy playing the surface, but I'm also finding it really nice for modulation inputs - e.g. using the surface as 3 or 4 x/y pads (a bit like intellijel planar)

oh wow, i recently got myself a salt plus salt+ :)
do you have your salt-soundplane project online somewhere, or can i write you an email asking beginner questions about this? i'm still very new to everything code-ish so salt is a bit intimidating...sorry to hijack this thread @randy!

wow, small world... Id never imagine there would be another person with both Salt and a Soundplane!
perhaps its just us 'Soundplaners' are adventurous type, who like to experiment!?

received your email and replied, but code is
(you'll want dev branch)

Lets start a new topic to discuss... so we don't hijack this one.

whilst I doubt any others have a Salt+Soundplane, its also relevant to anyone wanting to use a Bela or BelaPepper +Soundplane which is actually a cheap option for standalone soundplane use.
Also, others might just find the project interesting...
e.g. we can talk about the 'modes' ive implemented, and perhaps alternatives and that might prove interesting to @randy for this soundplane module to see how we are using the soundplane with eurorack.

I'm very interested to see what modes you have found useful, and any other details!

hi randy,
i know i know, sorry for my constant bumps of this thread...
is there some kind of foreseeable progress of this module?
excuse the 'nagging' question...i'm just curious and excited!

What I wrote above still holds: when Sumu is released, then I can devote some more time to this project.

Hello Randy,
It's a great new to know that you kept working on the Eurorack module Soundplane to CV.
I regularly read the forum to get news about this project because I am really interested in this module. It will allow us to have a direct control to sound, without a computer. What is more in the mind of this controller !
I'm so happy.
Thank you a lot !!

Hi Randy,
I hope you've survived the pandemic and are doing well. Hoping for a better and more productive year and health for all. Curious how the new Soundplane is coming. Getting tired of playing Aalto with substitute controllers.
Scott Moon

Hi Scott, thanks—it's been a difficult year! with the coming of Spring and, hopefully, a vaccine on the way I am finding myself more energetic and less distracted. Getting Sumu done is the first step to what will hopefully be a year of progress on all fronts.