Sluicer is a performance system for spatial audio improvisation, adaptable to various output channel configurations from stereo to high density loudspeaker arrays. In this work, two 20-voice, erratic synthesizers operate as a roving 'chorus' under the player's direction. Both synths have a series of multichannel effects designed to work specifically with high order ambisonic signals, allowing the player to create and alter spatial dimensions. As audio flows, the guiding action is like closing/opening gates in a lock on a waterway. The results are timbral and spatial churns, swells, floods and drains, motion in repetition, expansion, and contraction. Sluicer is programmed in Max with tactile interfaces being high resolution, multi-touch control surfaces and a DJ-style MIDI controller.