System for controlling low frequency acoustical directivity patterns and minimizing directivity discontinuities during frequency transitions

• Main Author: ROCHA; JEFFREY A
• Format: Patent
• Language: English
• Published: 12.09.2000
• Edition: 7
• Subjects: DEAF-AID SETS; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKEACOUSTIC ELECTROMECHANICAL TRANSDUCERS; PUBLIC ADDRESS SYSTEMS

An improved loudspeaker system which increases low frequency directivity and minimizes directivity discontinuities during frequency transitions includes a first low frequency transducer, a second low frequency transducer, a middle frequency transducer assembly and a middle frequency horn assembly having a small input aperture and a large output aperture. The middle frequency transducer assembly is attached at the small aperture of the horn assembly and directs a middle frequency acoustical signal into the horn assembly. The low frequency transducers and are mounted to opposite interior surfaces, preferably the top and bottom surfaces, of the horn assembly, and direct a low frequency acoustical signal into the horn assembly. A composite acoustical signal directed out of the horn assembly from the large aperture. The distance D1, measured from the upper transducer voice coil to the lower transducer voice coil, is substantially equal to 0.9048 of the distance D2, measured from the bottom edge of the output aperture to the top edge of the output aperture. Such a relationship between D1 and D2 results in a smooth transition and a substantially continuous acoustical beamwidth in the composite acoustic signal within low frequency to middle frequency crossover band.