Salt and Local H have the same simplistic approach to recording: Lay low on the overdubs. The former is a trio of Stockholm art-schoolers who took their studies of Minimalism quite seriously; the latter, an Illinois duo who were forced to go it alone after the bassist and rhythm gutiarist quit. (H’s sound has a bottom, though—the guitar is also rigged though a bass amp.) The result: Neither band cranked out more than they could handle on their records. Live, the songs on Auscultate and As Good as Dead, respectively, won’t be hard to get right. Mystery Machine opens at 8:15 p.m. at the 9:30 Club, 815 V St. NW. $10. (202) 363-0930.CP