MPA open-sourced, on sale

The complete design (PCB, bill of materials, firmware source code) for the MPA MIDI decoder has been posted under the Creative Commons Attribution-ShareAlike license. The source files can be found at the MPA support forum.

The MPA has been placed on sale at the Highly Liquid Store and will be discontinued after remaining inventory has been depleted.

The MPA (MIDI potentiometer array) is a general-purpose MIDI decoder with 8 independent 5V logic outputs and 4 independent digital potentiometer outputs.


Galanti Praeludium II console MIDI retrofit

Highly Liquid Forum user Jim U recently completed a MIDI conversion of a Galanti Praeludium II organ console for use with Hauptwerk virtual organ software. Three MIDI CPU units generate MIDI output from manuals, stops and pedals. Four MD24 units drive various LED indicators on the console. Additional project discussion can be found at The Organ Forum.




Highly Liquid user profile: Pastel Fractal

Chicago-based artist Alexander DeGraaf employs several UMR2 and MSA-T boards for his ongoing project Pastel Fractal. Alex uses MIDI control for robotics and live audience participation in addition to more traditional sequencing and synthesis functions.


Alex writes:

I have three sampling keyboards into which I have installed UMRs: two Yamaha VSS-30s and one Casio SK-8.  I use different samples on the keyboards for different compositions such as: my singing voice, a dog bark (sampled from SK-5), a TR-808 clap, a Doc Watson banjo riff, a Chet Atkins guitar riff, and some scatting sounds.

In my installation sculptures, I’ve used as many as two MSA-T MIDI Decoders to turn my MIDI note messages into voltage pulses for as many as fourteen small 24V solenoid motors. I’ve engineered these motors to reset immediately after being triggered, and I’ve connected them in various ways to percussive elements within the sculptures. In this way, I am able to MIDI-sequence robotic percussion strikes and sounds in sync with my compositions that are otherwise played by more conventional MIDI sound engines such as synthesizers, keyboards, and drum machines. The robotic percussive elements within the sculpture each provide a unique source from which sounds stimulate the inhabitant of the sculpture. I provide additional sound sources – besides robotic percussions and the main P.A. – by attaching small speakers to individual keyboards and drum machines so they may be hung around the sculpture or handed out to the inhabitants to pass and move about. Thus, inhabitants of the sculpture – also known as members of the audience – can contribute to the composition during a performance with these floating pieces of hardware by engaging buttons or keys within their reach.

More from Pastel Fractal can be found at Vimeo, Soundcloud, and Facebook.

Vintage Hammond drawbars as MIDI controller for Nord Electro 3

Highly Liquid Forum user cjfox rehoused a set of Hammond drawbars and replaced the original resistor wires with slide pots. Then he used a MIDI CPU to convert the drawbars into a MIDI controller for use with his Nord Electro 3.  The MIDI CPU configuration is posted in the project’s forum thread.


Yamaha CS01 MIDI retrofit project: detailed description and pictures

Special thanks to HL Forum member ElSmurf of Belgium for providing a detailed description of his excellent UMR2 MIDI retrofit module installation inside a Yamaha CS01. His words and photos follow.  

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I just finished work on my CS-01, so I thought I’d share the process with you.

My plan was to get the UMR-2 inside of the Yamaha without altering its functioning, so I could still be able to play it as is, with batteries and through the crappy speaker. This is way too much fun to do away with! So when I opened up the synth for the first time, I decided rather quickly that this would be the only place inside the enclosure that had enough real estate :

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This presented two obvious problems though – one corner would have to be cut, and I would have to drill a hole to let the LED housing pass through. Cutting the corner was fairly straightforward but drilling the hole for the LED proved to be more challenging. On the larger version you can see how close the hole gets to one of the UMR’s LED leads.

CS01 Large-2I then attached 3 small bolts with nuts, and super-glued these to the case of the synth.

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They kept the UMR in its place but also provided some elevation so the board sat ontop of the modulation destination slot.

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Here you can see the LED hole alligned with the hole in the UMR. At this point I thought I didn’t actually need the contacts for the program switch, since I didn’t read the manual the whole way through. This obviously made things a little challening when it was time to do the setup! :D

Once the superglue was dry I could unscrew the nuts and remove the UMR to solder the cables.

I embedded the resistor and diode in the cable so it wouldn’t take up too much space.

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Then came the scary part : drilling the hole for the MIDI socket !

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First a 2mm metal drill, followed by a 10mm wood drill, and then a 10mm metal drill.

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Then the big guns…

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Getting that huge 16mm drill to tear up the plastic just didn’t feel right so I felt it was my duty to take some photos to compare the drill sizes…

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I think you need a steady hand to drill in 30-year old plastic, especially considering how close you’re drilling to the edges. But everything worked out just fine.

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Next up was soldering the other sides of the cables to the synth.

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I have little experience with soldering on PCB, I mostly make only cables, so I was happy I had no shorts or burned through anything! After bending the cables everything kind of fit the way it fit before I put in the UMR.

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A little interlude – my screw storage system :

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Then came the hard part of doing the setup procedure. I had to put the synth on 2 small boxes so I could access the keyboard from below and access the UMR to short out the program switch. Which like I said proved to be tricky since the big contacts where gone!

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Luckily everything worked on the first try, so after doing the setup and teaching it the matrix, all I had to do was cut the black cloth that keeps dust out to compensate for the UMR, and put everything back together. This is what it looks like now :

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It took about 10 hours from start to finish, half of that time went in to cleaning – I dismantled the keyboard and cleaned every key separately. Now all I have to do is find my 2 missing slider caps – check the EG!

Luminth: Plug it in. Make music.

The Luminth Generative Music System is available for purchase on from now until June 13, 2013.

Click, turn, push+turn. Use the Luminth to generate melodies, percussive grooves, and ambient soundscapes. Make dramatic changes to the music with a single click. Dive deeper to make refined, subtle adjustments. Or let the software work autonomously to create music that morphs over time.



The Luminth is the new product from NTHSynth, a collaboration between Kevin Holland ( and John Staskevich (

Luminth Kickstarter Launches Thursday, May 16, 2013


The Luminth is a minimalist USB control peripheral. To use the Luminth, simply click, turn, and push+turn. The Luminth changes color with the music.

Luminth Orbiter is a generative music software application. Make dramatic changes to the music with a single click. Dive deeper to make refined, subtle adjustments. Or, let Orbiter work autonomously to create music that morphs over time.

The Luminth is the best way to control Luminth Orbiter software, but Orbiter is fully functional with or without the Luminth.

The Luminth and Luminth Orbiter will be available for purchase at 12:01AM EST on Thursday, May 16. Check on Thursday for a link to the Kickstarter project page and purchasing information.