In an age where live improvisation is a no-no because it might throw off the lighting technician's cues, Stereolab is a breath of fresh air. But be forewarned. There can be a downside to this kind of seat-of-the-pants random experimentation.

"It's really weird. When we're doing the improvised stuff onstage, things all go together and then coalesce. And then you realize you're playing some boogie riff or it sounds like prog rock or . . . ," Gane chortles in horror, ". . . Deep Purple!"

Stereolab is scheduled to perform on Saturday, May 20, at the Bash on Ash in Tempe, with the Chicago Underground Duo. Showtime is 8 p.m.