Microtonal Mathematics by Motorola

Isn’t this thing (pictured below) awesome looking? Part home organ, part accordion, part microtonal super-genius. In early 2018, we relocated our super-rare Motorola Scalatron from the keyboard exhibit hall into our workshop for a quick tweak in advance of our upcoming microtonal summit. 


Tim Warneck, our synth tech, tested the four internal power supplies to see if they were doing their jobs properly. Once confirmed, we connected the external speaker, fired her up and the fun began.

Enter George Secor, discoverer of the ‘miracle temperament’ and developer of the Scalatron.  George rolled into EMEAPP with a hoard of unique accordions and an eagerness to feast upon our Scalatron.  We came to discover that ours is unique version, in that it has a top-mounted jackfield in place of the standard synth-like face board. It is also one of the very few (3, actually) that has a multicolored accordion-like 240 button generalized keyboard instead of a home organ-style dual manual keyboard.

Over the next few days, George answered a myriad of questions as we delved deep into this unique machine. He explained to us how microtonal scales work and how mathematical ratios can apply.  He also treated the EMEAPP crew to a private concert on the ‘Moschino free-bass’ accordion, as well as on our vintage Rocky Mount Calliope and Hohner Electronium accordion monosynth. But, the highlight was seeing George perform a few numbers on our unique Scalatron, just as he did decades back when he first got involved in the instrument’s development.

We are so appreciative of people like George, the visionaries and innovators who make our musical worlds a more verdant and expressive place to create.

A few weeks after we wrapped up this summit, we happened upon an ultra-rare Motorola Scalatron Frequency Generator specifically designed to calibrate the keyboard on eBay. We figured that the Scalatron itself is so rare, we couldn’t pass up on this equally rare peripheral. Here is what the seller had to say:


“Here is a very interesting unit.  The Motorola Scalatron was an electronic keyboard instrument that could be calibrated to play microtonal music in live performance.  Apparently, only 20 of them were ever made. Some of them had a couple of normal looking keyboard manuals and some had “chiclet” keyboards with patterns of keys.  There was a separate company, Motorola Scalatron, Inc. That made them in the 1980s.

The keyboard could be calibrated to play virtually any scale system.  For instance, one sytem that was used had 31 tones to the octave. It came with what looked like a regular Motorola television monitor that was used to program the desired frequencies.  It displayed a split screen with what looked like Stroboconn type wheels which would be adjusted until they matched. One of the monitors was apparently on eBay sometime in the past according to some discussion forums I found and they mentioned that it must have had some kind of frequency generator to feed it.  I believe this unit is probably what would have done that.

This unit powers up and it does produce audible tones.  There is an on/off switch and indicator light on the lower left. There is a knob to select notes from the regular chromatic scale and another that changes the octave that is sounded.  The 3rd big knob on the left side says P/M Range below it and Pulse above. The pointer can be moved to 1, +2 or +4. There’s a small switch in the middle that can be thrown to either Variable or Chromatic.  There are 10 pushbuttons along the top and you can push any number of them at the same time and they will stay down until you push them again and they come back up. There’s a jack labeled Microphone in the lower left corner.

Probably the only one of these you will see this week!”

Couldn’t have said it better. Rare stuff indeed!!!

Written by Drew Raison, photography by EMEAPP