http://www.sourceaudio.net for more info.
Will Cady of Source Audio tours through each of the many effects settings on the Soundblox Bass Envelope Filter.
The Soundblox BEF is the bass envelope filter of choice for Mike Gordon of Phish, Kevin Walker of Justin Timberlake, Prince and Kanye West, Jai Dillon of Jason Mraz and many other premier talent bass guitar players.