Where do you get the impression that "microtonality is usually associated with an artificially constructed 24 tone chromatic scale"... I thought microtonality just meant dividing the traditional 12-tone chromatic scale into more than 12 tones.. Can't you divide an octave into 13 evenly spaced intervals, or into 999999999 ka-zillion equally spaced intervals and have that be considered microtonal? I've never heard of microtonality as strictly referring to dividing the the 12 semitones in half... Just curious.
whenever i hear people talk about microtonality they are usually talking about a 24 tone scale, or at the very least, an evenly divided scale other than 12. if you are using freedom of pitch like a trombone or voice or pitch bend wheel, i don't really consider that any kind of scale. i just consider that freedom of pitch, free pitch, or using any pitch you want, etc