I'm learning Scheme so I can program Impromptu (http://impromptu.moso.com.au/ http://impromptu.moso.com.au/) to control my MIDI setup live. I'm having a hell of

I'm learning Scheme so I can program Impromptu (http://impromptu.moso.com.au/ http://impromptu.moso.com.au/) to control my MIDI setup live. I'm having a hell of a time with macros and define-syntax; I have not yet found docs that explain those so I can understand them. I have played around with SBCL and Clojure, and can write macros in those languages. Don't know why I'm having problem with Scheme.