Abstract: An electroacoustic device comprises an array of electroacoustic transducer elements for producing a prescribed directional response pattern at a first frequency. Each element includes apparatus for restricting the frequency range of sound waves incident on said element so that the directional response pattern is invariant over a prescribed frequency band.

Abstract: An acoustic equalizer adapted for use with a microphone includes a resonator plate having front and back faces, a lip surrounding the plate and defining a first air cavity in the back face of the plate, and a plurality of apertures formed through the thickness of the plate, which apertures communicate with the first cavity. A boss is formed centrally on the front face of the plate. The boss is closed ended on one side and hollow interiorly to define a second air cavity. The first and second cavities communicate with each other through a central opening formed in the plate.

Abstract: An electroacoustic transducer has a front air chamber in front of the diaphragm that vibrates upon receiving sound waves or produces sound waves upon vibration and a back air chamber provided in the rear of the diaphragm. The electroacoustic transducer of the present invention further includes an auxiliary air chamber that is provided in the rear of the back air chamber that is coupled thereto by through holes. The auxiliary air chamber is divided into at least two smaller air chambers which are coupled to each other by a small orifice.

Abstract: A transmitter assembly for a telephone set uses a commercially available cartridge electric transmitter, by modifying the response curve. This is obtained by an adapter housing the transmitter with a first volume defined between the end of the transmitter and the end of the bore in which the transmitter fits. At the end of the bore there is an end wall with a hole therethrough, the hole covered with a layer of acoustic resistance material. A second volume is formed on the other side of the end wall, by a hollow formation on the wall of the transmitter housing of the handset. A slot is formed in the transmitter housing wall within the formation. The first volume provides damping, the hole and acoustic resistance material provides dB limitation at a particular frequency (1000 Hz) and the second volume and slot provide resonance at a second frequency (3000 Hz).

Abstract: A loudspeaker system has an enclosure of rectangular cross section with a baffle dividing the interior into first and second subchambers. Each subchamber has a port tube coupling the subchamber to the region outside the enclosure. The dividing baffle carries a woofer.

Abstract: A microphone, particularly for hearing aid application, said microphone providing a stepped response characteristic relative to frequency wherein low frequency sounds will couple to the associated hearing aid with a restricted amount of amplification, while providing an emphasis or higher amplification for the higher frequencies in the bandwidth of interest.

Abstract: An acoustic device which includes a sound generating element for generating sounds, a case member having an inner chamber for containing the sound generating element therein, and a sound conducting member extending from the case member for conducting the sounds generated in the inner chamber. In order to removably attach the acoustic device to a helmet, the acoustic device is provided with a holding member for holding the case member on the helmet. The sound conducting member is formed to extend from the case member to a location substantially corresponding to an ear of a wearer of the helmet.

Abstract: A miniature sounder having a diaphragm closing one end of a tuned chamber. The other end of the chamber communicates with the interior of a tuned housing. The chamber and housing are both tuned to the desired oscillating frequency of the diaphragm with the chamber resonant frequency comprising substantially three times the desired frequency and twice the housing resonant frequency.

Abstract: A miniature sounder having a diaphragm closing one end of a tuned chamber. The other end of the chamber communicates with the interior of a tuned housing through which an open-ended enclosure extends. The oscillating frequency of the diaphragm. The housing and enclosure are tuned to resonate at the desired frequency.

Abstract: An electrical acoustical transducer is provided having a piezoelectrical layer in a housing with a transducer plate. The transducer plate divides the housing into a front chamber and a rear chamber. In the rear chamber, there is provided a Helmholtz resonator for the attenuation of resonance increases. With the invention a Helmholtz resonator is designed such that its acoustical characteristics do not change through environmental influences. Instead of covering the resonator by means of a customary silk disk, several narrow slots are arranged in the carrier plate.

Abstract: A barrel-shaped diaphragm comprising a plurality of barrel stave-like strips with slits forming gaps between them is mounted on the vibration coil of a vibration generator that is based on a housing. A traverse bar which is based on the housing extends up through the center of the diaphragm. A sound conducting member that is cylindrical at the bottom and domed at the top is disposed on the vibration generator, within the diaphragm, and provides a gap of increasing cross-sectional area expanding toward the open upper end of the diaphragm. An inverted pot-shaped top is mounted on the upper end of the diaphragm. This top has an upper end wall with a depending sidewall that tapers in conically near the lower end. A plurality of struts extend obliquely from the tapered portion to the traverse rod to connect the lower end of the top, and thus the upper end of the diaphragm to the rod, and thus to the housing of the fibration generator.

Abstract: The invention concerns an electro-acoustical transducer with a transducer plate having a piezo electric layer and which subdivides the housing of the transducer into a front and back chamber. In the front chamber, means are provided for the attenuation of resonance increases comprising Helmholtz resonators and an attenuation disc. According to the invention, the Helmholtz resonators are designed in such a manner that their effective surface is not reduced in size by means of the attenuation disc or wafer. This is attained according to the invention in that slots are formed in a separating plate.

Abstract: An improved loudspeaker housing including a closed chamber in the shape of a triangular right prism closed at both ends. All of the three walls of the prism and rectangular in shape and two of the walls are at right angles to each other. A circular opening in a first of the two walls adjacent the right angle is provided for a loudspeaker which is attached to the outside of the first wall with the sound output of the speaker directed against the third, or hypotenuse, wall of the prism. An opening is provided in the third wall which is in the shape of an exponentially widening gap. A box is placed over the outside of the first wall enclosing the loudspeaker, and is lined inside with sound absorbing material.

Abstract: An electroacoustic transducer which includes a vibratile diaphragm operating at resonance has its narrow band width response characteristic increased by an order of magnitude by the use of a uniquely designed acoustic coupler in combination with the resonant diaphragm. The acoustic resistane presented to the resonant diaphragm by the acoustic coupler dominates the motional impedance characteristic of the transducer in the resonant frequency region of the vibratile diaphragm. The use of the inventive acoustic coupler reduces the Q of the vibrating system from a value in the order of 30 or more to the order of 8 or less.

Abstract: A cabinet for improving the sound output of an amplifier including an upright housing with a speaker mounted on the front, the front having one or more baffle openings, a device herein called a sound lens inserted in the baffle opening, the vibration of the speaker serving to induce vibration of the sound lens by condensation and rarefaction, by the speaker, of the sound waves to either side of the housing so that the sound lens functions as a supplemental and complementary sound source.

Abstract: An intrusion sensing device includes a sound frequency discriminating micophone having a diaphragm coupled to the atmosphere through a closed end resonating chamber having a length equal to one quarter the median wavelength of a relatively narrow band of sound frequencies peculiar to the act of intrusion into a building or the like. The diaphragm has a layer of piezoelectic material bonded thereto for generating an alarm signal only when sounds within such narrow band of frequencies are received within the resonating chamber. A linear amplifier connected to the microphone has an extremely low current drain, permitting continuous operation of the device while using small, low power batteries.

Abstract: An alarm wristwatch comprises a watchcase having a back with an inclined peripheral portion and a watchband attached to the watchcase at opposite sides. A transducer for generating an alarm signal faces a cavity provided in a rear portion of the watch case. A plurality of sound holes provided in the inclined peripheral portion of the watchcase back open into this cavity. The second holes are located within an angle of 45.degree. on either side of the longitudinal center line of the watchband so that they are not blocked or muffled by the arm of the wearer. The cavity and sound holes are so proportioned as to constitute a Helmholz resonator by which the sound produced by the transducer is intensified and efficiently transmitted to the exterior of the watchcase.

Abstract: A bass sound projection system comprises a cabinet containing at least one bass loudspeaker operating into a sound channel. The sound channel converges forwardly, relative to the direction of propagation of sound waves, of the loudspeaker to a throat and then diverges forwardly, relative to the direction of propagation of sound waves, of the throat to an acoustically open front end of the cabinet. The system may include a further bass loudspeaker and sound channel arranged as a mirror image of the first bass loudspeaker and sound channel, and the or each sound channel may be folded.

Abstract: An electroacoustic transducer assembly adapted to filter sound waves in a digital communication system incorporates a plurality of tandemly arranged tubular members and a transducer. Each tubular member includes an apertured plate end, a tubular cavity and an open end. The open end of each tubular member is secured to the plate end of the adjacent tubular member to form a housing with a divided longitudinal passageway. The open end of the housing is secured to the transducer. Every tubular cavity is partitioned into longitudinal sections by structural elements to inhibit cross mode resonance. The apertures, cavity lengths and structural elements are dimensioned relative to the cavity cross sections to suppress passage of sound waves outside a predetermined frequency band.

Abstract: A cabinet for improving the sound output of an amplifier, the cabinet being in the form of an upright rectangular housing with a horizontal partition dividing the interior into an upper and lower portion, the partition having a speaker opening and a baffle opening, a speaker being mounted in the speaker opening for upward projection of the sound into the housing upper portion, the speaker being connected to the amplifier, a sounding board within the housing upper portion inclined at an angle from the housing rear upwardly towards the housing front, a sheet of metal affixed to the horizontal partition and covering the baffle opening, the vibration of the speaker serving to drive the metal baffle by condensations and rarefaction of the sound waves to either side of the horizontal partition so that the metal baffle functions as a supplemental and complementary sound source.

Abstract: A speaker system comprised of an enclosure with a partition inside. The partition, set apart from a wall of the enclosure, has an aperture in it. A loudspeaker, mounted at the wall, has a speaker cone projecting into the aperture in the partition.

Abstract: A loud speaker having air communicating holes within the rear portion of the frame and facing the diaphragm is provided with regularly woven wire gauze formed of warp and weft wire threads of different diameter, which gauze covers the communicating holes to obtain a stable vibration damping effect.

Abstract: A speaker component mounted into a frame and related structure which is designed to reproduce sound in its most real and true form from an amplifier or other sound source and including a speaker mounting panel for the speaker component, a back wall, a front sound diffusion panel, surrounding a frame with a base resonance chamber and a tenor resonance chamber and including dowels to separate the partition components forming the chambers and further including a sound diffusion receptacle area with sound ports communicating the receptacle area with the atmosphere and where the resonance chambers are airtight with all the components combining to reproduce sound without interference especially in a quadraphonic system.

Abstract: A speaker enclosure for a stereophonic sound system is disclosed. The speaker is mounted in a chamber, the enclosure of which is connected to a tube of relatively long length and of circular cross-section. The construction is such that phase-inversion occurs so that the sound emanating from the rear of the speaker reinforces sound from the front of the speaker. The construction also substantially suppresses standing waves.

Abstract: A cabinet for improving the sound output of an amplifier including an upright housing having a horizontal partition dividing the interior of the housing into an upper portion and a lower portion, a speaker mounted in the horizontal partition and oriented for directing sound into the upper portion of the housing, a reflective sounding board positioned within the upper portion of the housing inclined at an angle relative to the horizontal partition, the sounding board being inclined from the lower back to the upper front of the housing dividing the upper portion into a forward and rearward resonance chamber, the sounding board reflecting sound outwardly from the cabinet, the sounding board having an opening therein of an area of one-half to seven-eighths of the vibrational area of the speaker, the opening being covered by a metal plate permitting fast sound transmission between the forward and rearward resonance chambers and a front panel covering the housing upper and lower portion, the upper portion of the fr

Abstract: A damping element comprising fiberous fuseable material shaped to form a cup-like member which may be inserted in the sound openings of an acoustic transducer to provide a selected acoustic resistance.