Earthquake (1974) had a really deep-set sound; thwomps of bass shook plaster loose from the ceiling and rattled your seat. That was Sensurround, the biggest bottom in all of ballyhoo, and only two other films ever emitted those freaky low freqs: 1976's Midway and the ever-loopy Rollercoaster. Tonight, thanks to the audio genius of Berkeley's own Meyer Sound, Sensurround will hit bottom, again. That is, not exactly Sensurround, but something lower than low. Rollercoaster itself is a series of gravity-defying plot twists and turns devised by a director with the bassest of instincts. Here, Timothy Bottoms (how fitting) plays a brooding maniac who's blowing up 'coasters as a way to extort cash, a cool million, to be exact. George Segal plays the safety inspector who has a nose for foul play, especially with all that cordite in the air. You'll see enormous wooden rollercoasters roar like thunder, then collapse into splintering cascades. Now put your hands above your head, if you dare, and wait for the woofers.