We're doing a renovation at the museum I work at and my boss has assigned me to look up a sound system he thought may be called parabolic audio. He wants to have a different speaker system for each exhibit that would be so focussed it wouldn't be heard at the next one He'd also like it to go and off automatically as someone walked by. I've done a lot of web research and can't find anything that seems to fit the bill. The parabolic systems I'm finding are either wide area like you would use at a sport stadium or used as a surveillance tape. I'd be glad to take responses offline.
Annmarie Zan
Isle a la Cache Museum