Abstract: The invention relates to a method to improve the acoustics of a room, preferably a hall, having a relatively minor space (10) from which sound waves, chiefly emanating from a musical instrument, and a relatively larger audience space (12), the outgoing sound waves being re-emitted via an amplifier device comprising a sounding board (20, 22) united with an electromagnet (26), an amplifier (21) and a microphone connected therewith, which device receives impulses from the sound source (14). The sound board (20, 22) and the electromagnet (26) form part of each of a plurality of wall elements (16) of such area and location in the audience space (12) that the sounding boards transmit to the listener a mixture of sound waves directly reflected from the sound source (14) and sound waves indirectly emanating from the amplifier device.

Abstract: A motion picture loudspeaker system is described in which the loudspeaker elements are integral with an acoustical boundary wall such that the characteristics of the vented box woofers are optimized. In order to overcome high reflection problems as sound from the tweeters is reflected by the motion picture screen and the acoustical boundary wall, frequency dependent acoustical absorptive material is attached to the wall to inhibit high frequency reflections with minimal effect on the bass optimization. The system includes the use of a steep slope crossover netowrk having a crossover frequency such that there is a first order match of the woofer and tweeter dispersion at the crossover.

Abstract: In various types of systems it is expedient to have a plurality of control consoles, each assigned a relative priority so that they may control the associated equipment in a predetermined hierarchy. The priority wiring requires only a pair of wires from one console to the next. A higher priority console, when activated, disables all lower priority consoles in the hierarchy and an indicator at each disabled console is activated to indicate the disablement. The indicator at the active console is not activated and the indicator at the highest priority console is, of course, never activated. Power to activate the disablement indicators is provided from the higher priority active console.