The Platonic Music Engine allows the user to manipulate the generated music in all sorts of interesting way. We'll discuss two of them related to how your instrument is tuned.
Western European classical music is dominated by the use of a tuning system known as “12 Equal Divisions of the Octave”. Many of the examples used throughout this site use this tuning. But the PME allows for just about any tuning imaginable. Including Pythagorean, Wendy Carlos’s Alpha, Beta, and Gamma tunings, Harry Partch’s 43 Tone System, and any equal division of the octave/interval (by ratios or cents). Here are some audio examples playing one octave of the selected tuning:
The first audio example uses standard Western tuning. The Pythagorean tuning will sound very similar to the first example. A discerning ear might hear that the perfect fifth, for example, is more “pure” sounding in this one. The third example should sound very odd as it divides the octave into 43 tones instead of the 12 we normally expect to hear. The third example divides the octave equally into a π number of tones. Or it does it as best it can given that pi is an irrational number. A consequence of this is that the octaves will sound slightly off (compared to more conventional tunings). We are able to use any number in that position from 0 to infinity (or whatever the biggest number our computer can handle) and including fractional numbers. And we are not limited to just octaves but can use any interval as we see in the last example as we divide a Just Intonation perfect fifth into 9 equal divisions following Wendy Carlos's Alpha tuning.
In Western music we most commonly tune our instruments such that the A above Middle-C (A4) has a frequency of 440 Hz. But no one is compelled to use that as a reference pitch. In fact all sorts of other reference pitches have been used like the currently en vogue A4-432 Hz.
The PME allows you to use any reference pitch you want. It has quite a few built in but you can also specify your own. The following is an example I made that uses A4 set to 100.5 Hz. No one would actually use this reference pitch but I chose it so that you can hear the difference. The music is exactly the same as used in the first example on this page but just with this different reference pitch.
Copyright 2015 David Bellows