Abstract: A hybrid transducer having mass and compliance loading for permitting operation at a lower frequency. The mass loading may include the use of one or more pistons to couple the energy to the medium. A ring configuration of the transducer is also disclosed. The ring moves with maximum motion at one position and minimum motion at a position 180.degree. thereto.

Abstract: An acoustic transducer for providing large displacements particularly at low acoustic frequencies is formed from a minimum of three curved shells which are attached to each other at their ends. The shells are driven by a ring or corresponding number of attached piezoelectric or magnetostrictive type rod or bar drivers. The curved shells are attached to the ends of the driver and vibrate with a magnified motion as the rods execute extensional motion. As the polygon expands the curved shells deform and produce additional motion in the same radial direction resulting in a large total displacement and corresponding large acoustic output.

Abstract: An electro-mechanical spring which provides amplified motion as well as a compliant structure for attachment, at the locations of maximum motion, to other mechanical or acoustical loads or elements. The spring produces motion in a directional orthogonal to the direction of a piezoelectric or magnetostrictive drive member connected along the major axis of a complete shell. The electro-mechanical spring provides a means for obtaining a low frequency large displacement piston type transducer.

Abstract: A directional flextensional transducer including a transducer shell capable of operation in odd and even drive modes and a transduction drive bar or the like. The transduction drive bar is excited in an even mode to impart extensional motion thereto and is simultaneously excited in an odd mode to impart inextensional motion thereto. The combined excitation causes the flextensional transducer shell to move unidirectionally.

Abstract: An acoustic transducer for providing large displacements particularly at low acoustic frequencies is formed from a minimum of three curved shells which are attached to each other at their ends. The shells are driven by a ring or corresponding number of attached piezoelectric or magnetostrictive type rod or bar drivers which take the form of a regular polygon. The curved shells are attached to the ends of the driver and vibrate with magnified motion as the rods execute extensional motion. As the polygon expands the curved shells deform and produce additional motional in the same radial direction resulting in a large total displacement and corresponding large acoustic output.

Abstract: The transducer of this invention provides a one-to-one input-to-output frequency relationship by the use of different magnetostrictive materials within the same transducer, the materials each having positive and negative strain expansion coefficients. The materials are selectively driven so that the transducer motion is in one direction for one polarity of the sinusoidal drive signal and in the opposite direction for the other polarity of the drive signal. The resultant transducer is capable of greater peak-to-peak excursion of the radiating face for the same length of magnetostrictive material than in the prior art biased-material transducer.

Abstract: The transducer is one that combines magnetostrictive and electrostrictive/piezoelectric transducer effects to form a transducer with improved performance. A transducer is provided which the two aforementioned effects are mechanically coupled in series allowing cancellation of the motion at one end of the transducer and maximization of the motion at the other end thereof. In an alternate construction, respective transducer types are connected mechanically in parallel in which the pressure may be cancelled on one side and increased on the other side of the transducer array. Either the velocity of pressure cancellation leads to a transducer element or transducer array with unidirectional properties. This device described herein may also be used as an intensity measuring instrument or as an acoustic sound repeater.

Abstract: A rod of magnetostrictive material has its ends placed between steel bars which provide compression on the rod by tensioning wires connected between the bars. Preferably, the wires are equally spaced along the bars from the rod so that when the wires are equally tensioned the rod is under no bending stress. The tension of the wires (and from this value, the compression of the rod) is conveniently determined by the freqency of vibration of the wires using known physical relationships between these quantities.

Abstract: A passive radiator, which may be a cone-type radiator is employed in a speaker system enclosure facing downwardly in the direction of the floor upon which the enclosure rests. The bottom wall supporting the passive radiator is preferably spaced a relatively short height above the floor by means of a plurality of legs such as four legs defining four output ports through which sound passes below the basic enclosure. The low frequency sound communicated through the four ports may be used to tune the resonator of the speaker system. With the use of the passive radiator maximum loading is obtained and interference effects are minimized. Also, upper base and mid-range internal reflections are prevented from being re-radiated. Because of the maximizing of loading a smaller passive radiator may be employed. Moreover, the concept of the passive radiator of this invention may be employed both in a single channel speaker system and a dual channel speaker system.

Abstract: A directional transducer is disclosed which includes flexural disc transducer elements mounted by their periphery to an inertial mass and connected to the transducer housing by their centers.

Abstract: The system provides improved bass response and stereo effect with the use of a plurality of speakers that are preferably disposed in a unitary cabinet. If two woofer speakers are employed they are disposed at an angle to each other and are disposed relatively close to each other to provide mutual coupling and improved bass response. Also, the speakers are spaced from a rear wall of the listening room so as to permit the coupling and also to enhance the spacial response by sound refelection from not only the rear wall but also the side walls thereby also providing improved sound realism through increased reverberation. Quadraphonic operation is also readily provided with the use of two cabinets.