The American Spirit

This is an experiment in arpeggiation and transposition through the MIDI capabilities of the Korg MS-20 Mini and Logic Pro X, and incorporates reverb to emphasize the harmonic relationship between the chords being arpeggiated. I also used stereo delay to soften the sounds. Both effects help create harmonic overtones because the resonance of previously triggered notes overlap with notes played after them.

I was interested in using soft sounds, and achieved this first by simply setting the synthesizer’s high-pass filter to a low value and the low-pass filter to 0. I then used Logic’s stereo and PlatinumVerb plugins to soften the sound further. This is the first time I’ve used stereo delay and I’m very pleased with its effects and plan on investigating it further. In addition to softening the synthesizer’s sounds, the reverb and stereo delay also contribute an atmospheric effect.

The process of arpeggiation and transposition is a matter of simple MIDI programming. The MS-20 Mini can send and receive MIDI signals via USB, and Logic is capable of taking these signals and applying MIDI effects in an external MIDI track. (Make sure to check the “Use External Instrument plug-in” box so you can apply MIDI effects and send signals back to the synthesizer.)

Here are two screenshots of the arpeggiator settings:

A few important details: In order to arpeggiate a sustained chord, make sure the latch setting is enabled and the mode is set to transposition. I set the keyboard to transpose the chords in the minor blues scale in the key of G. The first chord is Cm11, but only uses the notes C natural, F natural, and A#. The chords are then transposed by hitting a single key on the MS-20 Mini’s keyboard, which then becomes the tonic of the new chord. I don’t believe the arpeggiator creates inversions unless all keys of the inverted chord are pressed. Likewise, setting the first chord requires pressing all its notes. (I’m still note quite sure how this works given my understanding that the MS-20 only sends one MIDI note signal at a time.) I set the arpeggiation rate to 1/8 triplets played at 120 bpm.

One final note about the harmonic qualities:

The delay, reverb, and two-octave distance between the two oscillators combined with pitching down the second oscillator by a value of -2 (which I believe is a major second, though I’m uncertain the number values correspond directly with intervals) creates two layers of sounds which resonate over the notes being played, allowing the notes to harmonize.

The image in the video is a film photograph I took of a house in my hometown of Sacramento.


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