What is pitch bend and how is it applied?
Midi is set up to work with the twelve equal scale. Each note has a number between 0 and 127. The number is the number of semitones above the 0 note, with the 0 chosen to be five octaves below middle c. So 60 is middle c, 61 is c#, 62 is d etc. This spans the entire range of musically useful notes. However, when one wants to play notes “in the cracks between the keys” of a twelve equal keyboard, you need to bend the pitch up or down from its twelve equal position. Midi keyboards often have a pitch bend wheel – and when you move it, it bends the current note up / down in pitch – usually with a range of plus or minus a whole tone. So if you want the pure just intonation 5/4 for your e above middle c, at 386 cents for instance, you could make its Midi note 64 flat by 14 cents by moving the wheel by the appropriate amount. Unfortunately for this approach though, the wheel applies to the keyboard as a whole, so all the notes will get moved down, including the c as well. That’s not what we w
