Riff of the Day: Tom Sawyer synth "growl" (Rush)

I'd been wondering for a few days how Geddy Lee got what he calls the "growl" in Tom Sawyer--the first thing you hear after the drum hit:



Andy Skuse has a writeup of his attempts to figure out the growl, a set of .WAV files of his results, and a demo of the Digital Men playing "Tom Sawyer" with the resulting growl:



Not too shabby. Singer sounds more like Rik Emmett of Triumph than he does Geddy Lee--but Geddy Lee doesn't even sound like his 1981 self anymore.

As a bonus sound, Keyboard Magazine has the info for programming the "lead synth" sound for the song using a MiniMoog.