To many folks the tuba is inextricably linked with traditional German oompah-laden beer-guzzling songs performed by portly guys in lederhosen. Yet the instrument has a lengthy if near invisible jazz history, from serving a bass function in Dixieland to the big, polished bottom Bill Barber puffed into the modernistic big-band music of Gil Evans. The British tubaist Melvyn Poore has pushed the instrument in directions that would have made John Philip Sousa blush. His participation in avant-large ensembles (London Jazz Composers Orchestra and the King Ubu Orchestra to name two), to say nothing of the sublime European Tuba Quartet (whose Heavy Metal--Light Industry is terrific), has yielded thick, resonant textures, a surprisingly tensile lyricism, and mind-boggling harmonic possibilities. Yet it's on his 1994 solo album, Groundwork (Random Acoustics), that you can really get a sense of his metal. Poore uses a variety of sound-expanding electronic approaches, giving his thunderous drones and deep harmonies an even greater richness--whether opting for through-composed works or improvisation. German drummer Martin Blume has impressive improv credentials himself, and on recordings with people like Phil Minton and Georg Grawe he exhibits a remarkable light touch and a sure hand, accenting and interacting with the utmost sensitivity. This gig marks the duo's Chicago premiere. Wednesday, 9 PM, Empty Bottle, 1035 N. Western; 276-3600.