Have you ever witnessed the magic of the pipe organ at a mass in a cathedral?
The individual frequencies of an instrument’s overtone spectrum have subtle interactions with the tuning of the instrument’s notes and the harmonies played. Synchronizing the harmonies, the tuning and the timbre often makes the sublime difference between good and magical.
This first iteration of the PitchGrid modules (v2.0.1) aim at making this interaction explicitly audible.
The Microtonal V/OCT Mapper allows you to subtly change the V/OCT signal from the default equal temperament (where a semitone corresponds to 1/12V) to some historically relevant regular temperaments for the Western scale. You can pick from “Pythagorean”, where the perfect 5ths are tuned to the just 3/2 interval, “1/4-comma Meantone” with a just 5/4 major third and “1/3-comma Meantone” with a 6/5 minor third, and more. Since the overtone spectrum of the standard modular VCO is always harmonic, these tunings allow you to make certain intervals feel more “at rest” in your modular setup.
(Be aware though, that in any tuning besides the 12-TET, an F# and a Gb have different pitches. So when playing the black keys, you need to be mindful about the key you are playing in. The “Microtonal V/OCT Mapper” allows you to assign the black keys differently, depending on your context.)
Since other instruments do not necessarily have perfectly harmonic spectra, as is the case for the Hammond organ, for instance, these tunings do not work equally in any context. The original Hammond organ is (to a pretty good approximation) tuned to the 12-TET, and so are the partials that are controlled by the drawbars. The Microtonal Hammond implements a Hammond organ where the partials can be re-tuned according to a chosen temperament. You can either verify for yourself what a different tuning (like Pythagorean) does to the original Hammond sound, or make a Pythagorean Hammond organ that matches your altered tuning, and experience the difference.
If you want to learn more about the world of regular temperaments and isomorphic layouts, visit the interactive PitchGrid Web App.
I hope you have fun!
Best Peter