You might hear snatches of voice or string quartet or the occasional disfigured techno beat on Ryoji Ikeda’s 1998 album, 0ÞC (Touch), but the Tokyo minimalist generally prefers to work with sounds that aren’t so complex. He’s a musical molecular scientist, crafting irregular staccato rhythmic patterns, all-enveloping ambient hums, and jarring blasts of white noise from the most basic electronic tones; the universes he spins can be haunting and soothing or beautiful and frightening at once. With subtle precision he can twist a warm aural caress into a skull-piercing beam; he’ll maintain a high frequency for so long that it seems to linger even after the CD’s stopped spinning. Plus, and I don’t know exactly how he does it, his stuff has a physical presence you can interact with–moving yourself or your speakers around the room can significantly change the feel of a given piece….Second (Perdition Plastics), the second album from Chicagoan Kevin Drumm, opens with a high frequency that wouldn’t sound out of place on 0ÞC, but over the course of 24 minutes Drumm realigns, expands, and transforms that delicate sound into an undulating sepulchral drone that’s almost orchestral next to Ikeda’s structures. On his eponymously titled debut Drumm made a guitar sound like anything but, and on this new album he’s blurred the lines even more by blending guitar and synthesizer via computer; here he’ll use prerecorded material along with a laptop and a synthesizer. Like Ikeda, he gives his work a spatial dimension: as the sounds morph, they move through the speakers as if driven by the wind; for this performance he’ll employ a quadraphonic sound system for an even spookier effect. Drumm opens for Ikeda on Friday at 10:30 PM at 6Odum, 2116 W. Chicago; 312-666-4412 or 773-227-3617. The main reason Ikeda’s in town is to provide the musical component of OR, a spectacular multimedia piece by the Japanese group Dumb Type that uses dance, video, lighting, and sound to explore the theme of finite choices. Performances take place Friday and Saturday at 8 PM and Sunday at 4 PM at the Museum of Contemporary Art, 220 E. Chicago; 312-280-2660. Drumm also has another engagement this week, improvising with members of the Dutch avant-punk collective the Ex; see Bill Meyer’s Critic’s Choice for details. Peter Margasak