Tolga has been around for some time now, with a guitar with movable fretlets in channels under the strings to produce 9th tones and more. He gave a mindbending lecture at the GFA and also played some Ba?lama music as well as examples by contemporary composers.
Some microtonal timeout while waiting for a flight after the latest GFA – that’s Berta Rojas and Helen Sanderson watching!
More detailed exposition!
More Tolga!
Link