Headlining this month's SJ Bass Club, San Jose's premier monthly underground electronic event, is San Francisco DJ Carlos Alfonzo, who has a strong affinity for house music. His mixes are funky and well produced as well as experimental, trance-inducing and packed with crazy samples. He's been making house music for 13 years (and spinning it for 20), so he understands that making slight, subtle tweaks is all it takes to give that thumping bass a fresh, authentic flavor. The SJBC crew will be there too spinning some cutting-edge electronic music. Featured this Friday are Furan, Bendi, Justin Weisberg, Oons and Xtian.