Microposer is a Max For Live midi effect that spreads and squeezes incoming midi notes across the keyboard from a specified base note. It can be used to map microtonal synths onto a standard (12 tone) keyboard. It can also be useful for unconventional harmonic composition because of the method it uses to transpose incoming notes. Using the "Per Octave" setting, you can tell it how many notes you want to squeeze into one octave on the keyboard.
In order to microtune your music, you need a synth that is able to load tuning files so that you can use non-standard tunings. In the video, I use Serum to demonstrate the possibilities. Here is a comprehensive list of software synths that are capable of microtuning. https://en.xen.wiki/w/List_of_Microtonal_Software_Plugins
NEW IN VERSION 1.2: Visual Feedback showing which notes are currently active on the manual sliders.
Quick demo: https://youtu.be/nkPSLC7-Q1Y
Full description and tutorial: https://youtu.be/cTYUMiaCIXE
Here is a library of free tuning files to download: https://drive.google.com/file/d/1DunQOmXbof9xRS6Bipn9bgkFQQQQX1Vc/
Make your own tunings here (and check out the awesome music of Sevish):
Microposer plugin (amxd format)