Brit bassist Percy Jones is another enterprising musician who defies convenient description. "I'll do anything to make the bass sound like it usually doesn't," he claims. Improv-heads recall his trademark loping lines and chime-like harmonics from Brand X, one of England's premier jazz-rock outfits. Jones' latest band, Tunnels, is looser-limbed--without a loss of sheer muscle-power. Propelled by Jones' cerebral throb and the kinetic drums of Frank Katz, Tunnels features the electronic vibes of Marc Wagnon front and center. Local 506 in Chapel Hill hosts Tunnels Thursday, Feb. 27, at 9 p.m. The opening act is Onomata, the rambunctious Triangle-based cooperative that explores the heady soundscapes of space, groove and jazz of a non-traditional nature. Rest assured, they'll give the headliners a run for their money.