JJ Wiesler, MA/MST 2005-2006 CCRMA, Stanford University
MU220c - Omnichord Emulation Program


The Original Omnichord, made by the Suzuki Corp, is an electronic toy version of the autoharp. It is played by choosing a chord type (maj, min, or dim) and tonic on a matrix of buttons with the left hand and "plucking" the note on a pad with the right hand. The instrument developed a cult following in recording studios and with the use of typical guitar effects and studio trickery found its way onto many a record. The plug-in will be developed in Max and playable using just a computer keyboard and trackpad. It will have a simple built in sound which is a model of the Ominichord's harp-like tone, in addition it will put out MIDI and OSC for use with other sound generators or samplers.


04.14.06 Obtained Omnichord via ebay for use in modelling

04.15.06 Started working on the MAX patch for the pluck bar (screen shot below). I only want it to "pluck" (send a bang) the string in one direction. The vertical slider has a range of 0 to 1. At this point, the system sends out a bang when it crosses any interval of a 1/10th.


04.17.06 Started created images in photoshop for use in the emulation. Decided on a name: The J-Chord. I used the .jpg shown at the top of the site as a basis and did some tracing.


04.19.06 Found an ambisonic object for max/msp and Pd here

05.01.06 The laptop keys are now mapped to an array of buttons. This is accomplished using "key" and "keyup" as well as some selecting. When each key is pressed it ultimately sends a number 1-27. This triggers a interval pattern using "coll" which has an edittable preloaded text file. In this way I can add different button patterns if I decide to do so down the line.


05.04.06 After tweaking on it for about 48 hours straight...it is basically working. I have it outputting midi on MIDIYOKE for windows and using Reason as a sampler. Now let's see if I can learn to play it!


05.16.06 Alpha versions for testing: mac windows

05.25.06 Beta versions for testing: mac windows

Operating Intructions: The Jchord is basically a midi controller. It does have an internal beat player to be true to Suzuki's original. Its main intention is as a means to trigger your favorite synth (Reason, Arturia Moog, etc). Simply set the midi path in the bottom right pulldown menu, make sure this path matches the input path of your midi software and you should be good to go. The default should be general midi within OSX or XP.


omnichord Max/Msp