It wouldn't be James Dashow, would it? Not sure he is or was ever considered "minimalist". I remember hearing a performance of his -- most of them at the time (90's, not sure if early or mid or maybe even late 80's) were of the form, "Performance for ____ and computer generated tape", and one of which was voice. It was really good. Used FM synthesis to generate the tones, and sometimes it didn't sound like the human voice at all, and sometimes it sounded so close, you weren't sure when she (a soprano) stopped singing and the tape started.
Apparently, there's also one for tenor.
There's also the Yamaha FS1R -- which has some seriously vocal-like sounds, due to the formant-shaping -- but that wouldn't be due to repetition.
It's too bad scrypt isn't still around -- I bet he'd know.