Introduce some creative weirdness with MIDI inversion.
This month we’ll have a look at MIDI inversion, a simple but sometimes bewildering technique for breathing new life into your MIDI clips and streams. Inversion changes the relationship between notes in a chord or melody so that up becomes down while distance is preserved. For example, a major triad will invert to a minor triad, and a melody will invert vertically to a mirror image of itself. But the root of the inverted triad or key of the inverted melody might be anything. For the complete answer we need to know the ‘axis’ around which the inversion is measured. In Live it is possible to invert MIDI in clips or in real time. We’ll start with clips, where the process is easier to understand, and then build a MIDI Effect Rack for inverting MIDI on the fly.
For MIDI clips, the Invert button in the Notes tab of Live’s MIDI clip editor does the job, but in an unusual way. Instead of rotating notes around an axis, it measures each note’s distance above the lowest note in the clip (the ‘base’) and then moves it to that distance below the highest note in the clip (the ‘target’). That in itself can produce useful results, but it doesn’t give you control over the axis. However, that’s easily fixed by adding the desired top and bottom notes when the existing ones don’t suit. (Deactivate the added notes so that they don’t play in the inverted clip.) For example, if you want to have C as the axis of rotation, ensure that both the top and bottom notes are Cs, invert the clip and then transpose up or down by octaves to move the top C to the axis you want. In the middle example at the top of Screen 1, you would transpose the F‑minor chord down one octave to get C3 as the axis of inversion.
Inversion changes the relationship between notes in a chord or melody so that up becomes down while distance is preserved.
You’ll notice that the key usually changes when you invert. If you invert an ascending C‑major scale, you’ll wind up with a descending C Phrygian scale (Ab‑major scale played from C to C). You can work around the scale change by transposing after the fact, or as just described, by adding a note (an E in this case) above the original scale before inverting. One way to think about the scale change is to consider the sequence of intervals that make up the...