Ben Johnston Hears The Notes Between The Notes : Deceptive Cadence : NPR

The composer’s string quartets are known for their use of microtones — and their extreme technical difficulty. Just in time for his 90th birthday, The Kepler Quartet has finally recorded them all.

http://www.npr.org/sections/deceptivecadence/2016/12/31/507542859/ben-johnston-hears-the-notes-between-the-notes