Abstract: The present invention is directed to an apparatus for reproducing the bass components of an audio signal with a high degree of accuracy and minimal distortion, utilizing an enclosure of relatively small size. The apparatus comprises a substantially sealed enclosure in combination with a radiating diaphragm driven by an electromagnetic transducer, the principal diaphragm restoring forces being the elastic forces exerted against the diaphragm surfaces by the gaseous medium engaging such surfaces.

Abstract: The present invention is directed to an improved electroacoustic transducer of the type in which electrical conductors are mounted over a substantial portion of the radiating area of a movable diaphragm, characterized in that the electromagnetic forces exerted on the diaphragm are linear throughout the entire excursion of the diaphragm. The apparatus includes an acoustically transparent solenoid member having spaced-apart turns, the diaphragm being disposed within the area bounded by the solenoid turns, and having a conductor mounted on or comprising the diaphragm. A D.C. current is passed through the coil while the output of an audio amplifier is impressed on the conductor. The above arrangement is unique in that the flux density within the area bounded by the solenoid being essentially equal at all points, the conductor is subjected to essentially constant magnetic forces, notwithstanding its position within the solenoid.