Transcribe is a software package that is geared towards helping you analyse audio music tracks, usually for the purpose of working out the part of an instrument playing on that track, e.g. a guitar solo.
If you've ever been frustrated by trying to work out a blindingly fast guitar solo by constantly stopping and rewinding a small section of a CD, then Transcribe is well worth a look. With it, you can slow down a track to a fraction of its original speed without changing pitch, transpose it to any other key you like, and loop continuously over any small section of the track...
