Kepler Quartet has been played on NTS shows including Le Jardin w/ Sarah Davachi, with String Quartet No. 9 (1988) first played on 20 July 2018.

"The Kepler Quartet was formed in 2002 by violinists Sharan Leventhal and Eric Segnitz, violist Brek Renzelman and 'cellist Karl Lavine to record the complete microtonal string quartets of composer Ben Johnston."

http://www.keplerquartet.com/