Herb's Postscript from the Park Lane Hotel
The super cool Rudy Dupuy of Dupuy Acoustique (in Congers, NY) says he used to make loudspeakers, but then he realized that the time-delayed and out-of-phase reflections from the wall behind the speakers always sabotaged any hope of loudspeaker coherence. So he stopped making speakers and developed the tunable Phase Restoration Acoustical Panel (PRAP).