Abstract: The back to back mounted compound woofer that improves sound quality by minimizing mechanical vibrations is provided. The woofer speakers of the present invention are under compression allowing for more efficient cone motion control resulting in a lower cutoff and thus, resonant, frequency. Since the compound woofer of the present invention minimizes size, material, and electrical and custom components, it is inexpensive to manufacture. A housing provides an enclosure for the compound woofer. The housing includes opposed sidewalls or side plates, each having a coaxial opening. Each of two speakers is mounted on a respective coaxial opening of a respective sidewall. Additionally, the two speakers are mounted back to back, i.e., with their magnet structures in close proximity to one another. In one embodiment, the magnet structures are coupled to one another using a flexible sealing compound such as putty. In another embodiment, the two woofers share a common unitary magnet structure.

Abstract: An improved transducer which includes a rigid frame and a permanent ring magnet mounted to the frame. A small bobbin, preferably formed of aluminum foil, is sized and arranged to fit within the open end of the magnetic gap while permitting motion of the bobbin therein. A voice coil is wound on the bobbin and connectable to receive an audio signal, similar to a conventional voice coil driver system. A pair of flexible, curved diaphragms are disposed in the frame, generally free to move except for a distal end of each diaphragm which is fixed to the frame. The diaphragms can be of generally cylindrical or partial-cylindrical shape.

Abstract: An audio transducer is disclosed that has a piezoelectric driving element and a diaphragm having a sheet configured as a flat, curvilinear plane. A lightweight, rigid bridge element connects the piezoelectric device to the diaphragm. Several bridge configurations are shown that emphasize or reduce various characteristics such as frequency response and vertical dispersion. Also, several diaphragm configurations are disclosed in which the diaphragms have as few as a single diaphragm sheet or as many as four sheets. In each case the diaphragm sheets are configured as a flat, curvilinear plane.

Abstract: An audio transducer is disclosed that has a piezoelectric driving element and a diaphragm configured as a flat, curvilinear plane. A lightweight, rigid bridge element connects the piezoelectric device to the diaphragm. Several bridge configurations are shown that emphasize or reduce various characteristics such as frequency response and vertical dispersion. Also, several diaphragm configurations are disclosed in which the diaphragms have as few as a single diaphragm sheet or as many as four sheets or more. In each case the diaphragm sheets are configured as flat, curvilinear planes. A resonance damper is provided comprising a resilient membrane having a plurality of resilient flaps. The damper is resiliently coupled to the piezoelectric device by arranging adjacent flaps to press against opposite sides of the piezoelectric device.

Abstract: An audio transducer having a having a single magnet and an adjacent iron bar spaced apart to define a gap. The bar has two edges, each positioned near one pole of the magnet to define a respective field across the gap, with the fields being oppositely polarized. An electromagnetic coil is positioned to ocsillate within the gap in response to an audio signal. The transducer is assembled with an unmagnetized magnet. The magnet is magnetized after assembly by application of an external magnetic field.

Abstract: An audio transducer includes a rigid base plate and a flexible foam element attached to the plate. The foam element has a "B" shaped cross section, with a plastic film diaphragm conformally attached to the dual semi-cylindrical front surface of the foam element. The foam element defines a large circular bore for receiving a magnet assembly attached to the plate, with a electrical coil attached to the diaphragm and received within a gap defined within the magnet assembly. The plate and diaphragm are sealed to the foam element to provide an environmentally sealed chamber within the bore.

Abstract: An audio transducer having a cylindrical diaphragm molded with contoured ridges. The diaphragm includes at least two lobes, each extending from a central expanse to the transducer frame. The lobes may have different radii and different angular arc lengths. A driver attached at the central expanse may include a double-sided etched coil, or may be provided by an electrostatic driver having a charged filament attached to the diaphragm. The transducer diaphragm may include a central third lobe having different size and structural characteristics to provide added low frequency response. The transducer may be configured to provide omnipolar sound radiation with opposed spaced-apart semi-circular cylindrical diaphragms arranged to pulse symmetrically toward and away from each other.

Abstract: An audio transducer having a voice coil formed by an etched, flexible circuit having an elongated, oblong spiral loop and rolled into a cylindrical tube. The coil cooperates with a magnetic structure including a circular, central magnet having a front north pole plate and rear south pole plate sized to fit closely within the cylindrical coil, and an annular outer magnet having a south front pole plate and a north rear pole plate aligned with the pole plates of the central magnet. The aligned magnets define annular front and rear magnet gaps between the respective front and rear pole plates with front and rear radial magnetic fields of opposite polarity formed across the respective magnet gaps. The spiral pattern etched on the coil is configured so that current flowing in the front portion of the coil within front gap magnet flows in an opposite orbital direction from current flowing in the rear portion of the coil within the rear magnet gap.

Abstract: An audio transducer having a pair of magnets supported to provide a magnet gap within which a flexible diaphragm supporting an electrical coil is received. The diaphragm is formed of a pair of flexible cylindrical webs joined at their centers to support the coil within the magnet gap. The diaphragm is provided with a row of perforations on either side of the gap to provide flexibility and is aligned centrally within the gap by tab portions partially cut from the diaphragm and folded to be adhered to the magnets.

Abstract: An audio transducer having a pair of magnets supported to provide a magnet gap within which a flexible diaphragm supporting an electrical coil is received. The diaphragm is formed of a pair of flexible cylindrical webs joined at their centers to support the coil within the magnet gap. The diaphragm is provided with a row of perforations on either side of the gap to provide flexibility and is aligned centrally within the gap by flexible foam strips attaching the magnets to the diaphragm.

Abstract: An improved audio transducer includes a diaphragm having a pair of cylindrically-shaped webs that provide greater bandwidth, reduced distortion and greater horizontal dispersion of sound. The audio output of the transducer is further improved by forming the diaphragm of a polyvinyl fluoride film. Other improvements include the use of damping pads to damp internal sound waves and damping strips on the diaphragm to minimize distortion at the resonant frequency of the transducer. In one alternative embodiment a laminated diaphragm is used to damp resonance in the high-frequency end of the transducer operating range.

Abstract: An audio transducer includes a diaphragm having webs extending, along a central expanse between opposed magnets. Flexible centering tubes extend through the expanse and are secured to a clamp which is adjustably fixed to the transducer frame. Each of the flexible centering tubes provides passive lateral centering of expanse above a predetermined frequency and actively restrains movement of the expanse in the plane thereof when the transducer is operated at or below the predetermined frequency.

Abstract: An improved audio transducer includes a diaphragm having a pair of cylindrically-shaped webs that provide greater bandwidth, reduced distortion and greater horizontal dispersion of sound. The audio output of the transducer is further improved by forming the diaphragm of a polyvinyl fluoride film. Other improvements include the use of damping pads to damp internal sound waves and damping strips on the diaphragm to minimize distortion at the resonant frequency of the transducer.

Abstract: An audio transducer for reproducing sound. The transducer may be utilized as a loudspeaker or a microphone. The transducer comprises a frame on which is mounted a pair of opposing permanent magnets, which produce opposing magnetic fields and a flexible diaphragm which encloses an elongate looped coil and passes through the magnetic field. A signal of variable amplitude in the coil accompanies movement of the diaphragm in what is described herein as rolling, linear movement.