Articles / Gear

Randy George's MIDI Merlin

Always wanting to push his theremin performances further outside the box, Randy George has emerged from his laboratory with a new creation that is part teaching tool, part instrument, and very flexible. Say hello to MIDI Merlin!

MIDI Merlin is a MAX-based application that’s packed with real-time performance and audio-to-MIDI features and is versatile enough to function as an instrument or as an ear-training aid.


Here’s a quick look at the feature list:

  • audio to MIDI conversion for monophonic instrument sources (e.g. theremins)
  • translation of continuous MIDI data into momentary note-on/note-off messages
  • onscreen keyboard display reflecting note preview and currently sustaining notes
  • integrated tuner displaying the pitch of the audio input signal
  • toggle sustain function that automates the release of notes by suppressing note-off messages
  • preset memory slots for temporarily saving sequences of notes or sequences of toggle sustained notes
  • double-time function enabling note-on messages to be generated by the “up” motion of the note-on function
  • customizable keyboard shortcuts and MIDI input values with “MIDI learn” functionality
  • three selectable sources for continuous data: MIDI CC, Audio Input pitch/amplitude, and mouse cursor x/y position
  • aux MIDI input for displaying alternate note information in the onscreen keyboard feedback display
  • route MIDI data from one device and specific channel to another device with specific channel

MIDI-Merlin is built around the Nintendo Wii™ remote as its wireless interface. When used along with a MIDI controlled synth or sampler, it can function as an instrument on its own, thus converting the Wii™ remote into a new kind of wireless MIDI instrument. Think of it as a customizable virtual MIDI theremin.


For thereminists, MIDI Merlin can generate MIDI messages from the integrated pitch tracking and audio-to-MIDI feature.  This can be combined with other features to create new gesture controlled performances.  For example, by feeding the theremin's audio signal into the application and controlling the Wii™ remote with the 'volume hand', a theremin player can interact with MIDI by triggering MIDI messages specific to the pitch of the input signal.

MIDI Merlin can also function as an ear-training aid by providing visual feedback from an integrated tuner and onscreen keyboard combined with the instant reference tone generation of triggered MIDI information.

Other aspects of theremin playing can also be exercised and improved with MIDI Merlin. Areas of playing including vibrato depth and consistency, note transition time, and interval width tuning can all be extracted from the audio visual feedback system.

The app is hosted at Cyling74’s website and is free of charge. It’s currently only available for Mac, but he’s open to a Windows version if there’s enough interest. 

A big thanks to Randy for sharing this with us!  Be sure to check out his Facebook page and his YouTube channel for all sorts of theremin goodness.