I'm about to embark on a sound design project for an interactive piece that will be a public installation. It will always be surrounded by people in a large space (think a trade show floor or lounge-type area), so human background "walla" and environmental noise will always be present. The speakers themselves are a pair of small, one-driver units built into the device.
While I have my own research and guesses as to how to approach this (and am prepared to do lots and lots of tests/testing), does anyone have any techniques or theories that could help guide sound design that would cut through such human mid-range background noise as to be audible? (The goal here is aural feedback of touch interactions, not the creation of super-detailed sound effects.)