You are not alone, 10.9.1 has caused a lot of audio problems for a lot of folks.
https://discussions.apple.com/thread/5482053?tstart=0

I've heard from some developer friends who are on the 10.9.2 beta test group that the next update from Apple fixes a lot of audio woes, including a bunch of USB audio things that Mavericks (10.9 and 10.9.1) broke.

Just be patient 10.9.2 is due to hit any day now, and it should fix this problem along with a bunch of others.

Hopefully this helps.

- Jay


MacPro 5,1/12 core@3.46GHz -- OS X 10.15.7 -- ATI 7970 -- 32 Gig RAM -- Crucial 500GB OS SSD -- Samsung EVO 1TB Audio/Sample SSD -- BIAB 2023 -- Logic Pro X -- Cubase Elements 11 -- Too many plugins