It's both audio software yes, but Overtone is an layer on top of a (very impressive) C++ real time signal synthesis system.
SOUNDLAB on the other hand is a synthesis toolbox written from scratch, which probably consists of fewer code than the Overtone wrapper.
Edit: So, Overtone is not SOUNDLAB for Clojure. One would rather compare SOUNDLAB to Overtone's underlying SuperCollider.
It's both audio software yes, but Overtone is an layer on top of a (very impressive) C++ real time signal synthesis system.
SOUNDLAB on the other hand is a synthesis toolbox written from scratch, which probably consists of fewer code than the Overtone wrapper.
Edit: So, Overtone is not SOUNDLAB for Clojure. One would rather compare SOUNDLAB to Overtone's underlying SuperCollider.