Abstract: A modular loudspeaker system of uniformly sized and shaped loudspeaker modules permits hanging of a plurality of the modules in a wide variety of desired configurations. Each module has a pair of side walls with recessed upper and lower marginal edge portions and an integrally formed reinforced connectable structure that spans between the recessed edge portions for reinforcement of the module across its side. When several modules are hung vertically, the vertically aligned reinforced connectable structures reinforce the system along its entire length. Three module types are disclosed, with one type adapted for removable mounting therein of a speaker horn via a quick release hub. Overall, the system provides optimum versatility in adapting to the acoustical requirements of a wide variety of performance venues.

Abstract: An anechoic chamber having a rotatable corner in the nature of a rotating door which permits the selection of a desired one of four right angle corners to be introduced into operative engagement with the room. In the use of the anechoic chamber, with a selected corner in position facing into the chamber, a sound seal is provided about the periphery of the frame of the rotating door. The walls of the anechoic chamber are covered by sound absorbent material, and one of the four corners which may be positioned in the chamber through rotation of the rotating door contains surfaces similarly covered by sound absorbent material. Another of the four corners is a trihedral corner including a base, or floor, for supporting a corner speaker.

Abstract: A small dimension low frequency loudspeaker has a folded exponential horn which provides a unitary curved sound path from an electroacoustic transducer at the throat of the horn to a volume into which sound is radiated at the mouth of the horn. The length of the horn is such that, at an exponential rate of expansion between the throat and the mouth, the mouth, when it is bounded by at least one planar surface, such as a floor, a ceiling, and/or walls of a room, has adequate area to enable reproduction of low audible frequencies. An illustrative embodiment of the low frequency loudspeaker has an effective low end cut-off frequency of 55 Hz. A loudspeaker system, including a low frequency loudspeaker as well as midrange and high frequency loudspeakers and an LC crossover network, is also disclosed.

Abstract: A low frequency loudspeaker apparatus includes a folded exponential horn which is divided to provide a bifurcated curved sound path from at least one electroacoustic transducer that is positioned at the throat of the horn to a volume into which sound waves are radiated that is located at the bifurcated mouth of the horn. The mean length of the folded exponential horn is such that, at an exponential rate of expansion between the throat and the bifurcated mouth, the area of the mouth is adequate for reproduction of low frequencies in the audible range. An illustrative embodiment of the low frequency loudspeaker apparatus has an effective low end cut-off frequency of 38 Hz. and affords 99 dB SPL output at three meters with one watt input which corresponds to about 20% efficiency measured in free space. Presence of a single boundary surface, such as a stage floor adjacent the mouth of the folded exponential horn, improves amplitude response by 3 to 6 dB.

Abstract: A small dimension low frequency loudspeaker has a folded exponential horn which provides a unitary curved sound path from an electroacoustic transducer at the throat of the horn to a volume into which sound is radiated at the mouth of the horn. The length of the horn is such that, at an exponential rate of expansion between the throat and the mouth, the mouth, when it is bounded by at least one planar surface, such as a floor, a ceiling, and/or walls of a room, has adequate area to enable reproduction of low audible frequencies. An illustrative embodiment of the low frequency loudspeaker has an effective low end cut-off frequency of 55 Hz. A loudspeaker system, including a low frequency loudspeaker as well as midrange and high frequency loudspeakers and an LC crossover network, is also disclosed.