Abstract: An analog signal which forms part of a digital audio recording system is split into at least two signal paths in one of which it is delayed slightly before being recombined with each signal of the other signal path or paths. The delay can be effected by using a multistage filter in the delay line, which causes the signal in the delay line to be delayed for a period of time equal to a fraction of one cycle of the sampling frequency of the associated digital recording system. The slight delay eliminates or minimizes undesirable phase shifting which is created in the analog signal by the sampling frequency.

Abstract: The efficiency of a loudspeaker housing is substantially increased by incorporating in the housing, in the form of a lining or stuffing, a quantity of goat's hair, preferably mohair.

Abstract: The upper peak impedance of a speaker or woofer that is mounted in a base reflex or ported enclosure is dampened by designing the enclosure so that the speaker is mounted in the upper end of a horn formed in the housing, for example, by inclining its front wall to the vertical, so that its upper edge is located closer to the rear wall of the housing than its lower edge. The interior of the housing between the speaker and the housing port thus has a cross sectional area which increases progressively from the upper to the lower end of the housing, and thereby functions as an acoustical transformer, which dampens the cone of the speaker particularly in the area of its upper resonant frequency.

Abstract: At least one active and one inactive speaker element or radiator are mounted in each of a plurality of differently sized speaker housings, each of which housings has a fundamental resonant frequency different from each of the other housings. An audio signal is applied simultaneously to each of the active radiators, which in turn create in each housing acoustical wave forms which drive the associated inactive speaker.