Abstract: An acoustic projection system in which a reproducer array disposed in a listening chamber and operating in conjunction with a signal processor coupled to right and left channels carrying stereophonic signals, acts to project sound into the chamber in a manner substantially recreating the three-dimensional ambience of an original sound source composed of a central zone flanked by left and right zones. The processor extracts from the two channels a first power output derived from the sum of the right and left channel signals, a second power output derived from the difference between the left and right channel signals, and a third power output derived from the difference between the right and left channel signals.

Abstract: The aimed launching of projectiles is simulated by means of an electroacoustic transducer which is energized to emit a beam of sound waves, preferably at ultrasonic frequency. A cooperating target also employs an electroacoustic transducer and apparatus for indicating reception of the sound beam by that transducer. The emitter transducer may be mounted in a simulated firearm, or other projectile launcher, while the receiver transducer may be mounted on a simulated target.