The original drum 'n' bass Dub reggae started by accident. One night in 1967, Jamaican DJ "Ruddy" Redwood went to a party, intent on playing a hot-off-the-presses tape of the Paragons' "On the Beach." He soon discovered, however, that the engineer had forgotten to put the vocals on the track. It didn't matter in the end; the audience went crazy anyway. Redwood told sound-system impresario Duke Reid about the excitement the song caused, and Reid began adding the simple backing "instrumentals" to singles as B-sides. Over time, the sound evolved into "versions," vocal-cleansed tracks that other DJs sang over, and then into dub as we know it today, with heavily produced effects, echoing vocals, and thick drum and bass.

The Bay Area's primary source for live dub, the weekly club night "Dub Mission," started with equal serendipity. In the late '80s Sep Ghadishah began DJing at KUSF-FM, playing mostly indie rock and experimental sounds -- until she came across Tackhead, a group consisting of British producer Adrian Sherwood and three members of the house band for the hip hop label Sugar Hill.

"Tackhead combined an interest in dub and production with hip hop," Ghadishah says via phone during a break from a New York trip. "For me and a lot of other people, they were a portal back into dub."

Ghadishah immersed herself in the sounds of Sherwood's On-U label, which in turn led to the works of older artists like King Tubby and Bim Sherman. "It was like working back from a branch to the root of a tree," she says. When she began playing dub on her radio show, a funny thing happened: Listeners called up to ask where they could hear the tracks live. Realizing that there wasn't an outlet for the music, she started "Dub Mission" in September 1996 at the Elbo Room.

Five years later the event is still going strong. Ghadishah credits the club's owners, a supportive, open-minded community of fans, and her fellow DJs, J. Boogie, Maneesh the Twister, Vinnie, and Ludichris, with the night's success. "This wasn't a lucrative gig when we started," Ghadishah says. "They all just really loved dub and wanted a chance to spin it."

Now the riddim comes full circle, as Sherwood performs on Sunday, Sept. 2, at the club's fifth anniversary party. For his first local show in over four years Sherwood will spin a live mix of old, unreleased On-U tunes and upcoming new tracks, with vocal help from Ghetto Priest. Ghadishah and the other resident DJs will play as well. Tickets are $12 before 11 p.m.; call 552-7788 for info.