microtonal modulations

Jay here,
All those John Starret/Neill Haverstick cuts are full of interesting
modulations, as John says. I'm surprised how easily my trombone-slide arm
can find those places.
Another wondrous source of such modulations is that amazing vocal music from
the Republic of Georgia. It's usually a 3-voice polyphonythat consistently
modulates for extended periods up or down by an interval I've not
determined, but anyway, they always find their way back to the original pitch.

Jay Williams wrote...

>Another wondrous source of such modulations is that amazing vocal music
>from the Republic of Georgia. It's usually a 3-voice polyphony that
>consistently modulates for extended periods up or down by an interval
>I've not determined, but anyway, they always find their way back to the
>original pitch.

Can you recommend any recordings?

-Carl