Common Music switched from Common Lisp to Scheme in 2008 (and also supports SAL for people who don't like the Scheme syntax); it uses the S7 Scheme interpreter included with sndlib. Actually Common Lisp Music is neither Common Lisp anymore, but a C library and part of the mentioned sndlib (with some language bindings).
And I use the same one in Scheme for Max and Scheme for Pd.
s7 is by Bill Schottstaedt, one of the godfathers of computer music and the author of Common Lisp Music and the Snd editor. It has really nice design decisions for the composer-programmer.
