Abstract: A microprocessor-based ALC (automatic level control) system, for original manufacture or field maintenance and retrofit, providing the stability, reliability and longevity of digital solid state implementation along with ALC characteristics calibrated to one or more programed sets of ALC performance specifications. The ALC system can be embodied as a professional audio ALC amplifier with a purely analog main signal path including an ECA (Electronically Controlled Attenuator) controlled by a highly stable microprocessor-based signal level transducer, an ALC calibrator that can be incorporated into any system, ALC system or ALC-related module thereof, or deployed as stand-alone test equipment, to provide ALC performance and/or automatic recalibration of existing ALC circuitry, compensating components thereof to meet programed ALC performance specifications and thus remedy problems and shortcomings relating to stability, reliability, longevity and/or ALC performance.

Abstract: Acoustic wave "diffractor" labyrinth(s) are positioned obliquely in front of sound producing transducer(s) to cause very wide angle dispersion of the sound waves projected from said transducer(s) into said labyrinths. The labyrinths may consist of a complex of bent and folded chambers. This system causes depolarization of the sound waves projected from the transducer(s).

Abstract: A process and apparatus for killing organisms in situ within a host by means of successive short-duration high-current-density pulses of electricity of alternately opposite polarity. These pulses are passed through the host and concomitantly the organisms for a period of a few seconds. The cellular structure of the host is not destroyed, nor is the temperature thereof appreciably elevated. The current is conveyed to the host from electrodes immersed with the host in a weak electrolyte. The pulses are formed by phase-controlled thyristors.