Abstract: An active muffler for use in motor vehicles comprises a sensor, an electronic control responsive to the signal generated by the sensor for producing a drive signal delivered to a transducer which emits cancellation pulses phased 180.degree. from the sound pressure pulses passing through a conduit, where both front and rear sides of the transducer are acoustically coupled to the conduit to improve the efficiency of the transducer operation. Preferably, the acoustic coupling comprises an enclosed chamber including a port for communicating with the conduit which can be tuned to resonate at predetermined frequencies. When both sides of the transducer are so coupled to the conduit, the transducer has increased efficiency over a broad band of frequencies, and the frequency band can be broadened at the low end as required to accommodate the frequencies generated by a source of noise.

Abstract: A stereophonic loudspeaker system which includes at least two channel loudspeakers and a centrally located feedback control loudspeaker. Each channel loudspeaker incorporates an electrically driven low frequency electrosonic transducer and a sonically driven electrosonic transducer sonically coupled together to form a sonic oscillator. The sonically driven transducer responds to sound and sonic vibrations produced by the electrically driven transducer to produce sounds and an electrical output signal. The feedback control amplifier includes a plurality of electrosonic transducers interconnected sonically and electrically. The transducers of the feedback control loudspeaker respond to the electrical signals from the sonically driven transducers of the channel loudspeakers to interactively enhance the production of aurally pleasing low frequency sound from the loudspeaker system.

Abstract: An electronic siren apparatus has a primary horn with a throat which splits into matched secondary horns each having sides, an output end, a longitudinal axis, and a circumference. The secondary horns are folded back toward and around the primary horn and throat and the portions of the circumference of each end are joined. The folded secondary horns and the joined portions form a cavity which houses the primary horn and throat. A driver is operatively joined with the throat and is contained within the cavity for generating sound which is transmitted through the throat and primary horn, and then into each secondary horn and out the output ends in phase and amplitude matched relation. The area of the primary horn and the combined areas of the secondary horn, satisfy the equation ##EQU1## where x is the distance measured along the axis from the throat, cosh is the hyperbolic cosine function, d is the diameter of the primary horn and the combined diameters of the secondary horns, d.sub.

Abstract: A system for the multichannel reproduction of sound in which a plurality of loudspeakers connectable to a surround sound processor is disclosed. Circuits for adapting the processor to provide left and right side output signals are also disclosed. Left and right side dual loudspeakers are disclosed wherein each dual loudspeaker contains two independent drivers, one facing the front and the other the rear of the listening area, the front-facing drivers being connectable to the left and right side output signals and the rear-facing drivers being connectable to the corresponding left and right rear output signals of the processor.

Abstract: A compound driver loudspeaker system combines a single exterior radiating loudspeaker with a plurality of internal auxiliary loudspeakers in a cabinet. The cabinet has an external baffleboard and an internal baffleboard, the external baffleboard having a single baffle cutout for receiving the radiating loudspeaker and a plurality of internal baffleboard cutouts for receiving each of the auxiliary loudspeakers. The baffleboards and loudspeakers define a desirable air chamber between them. The auxiliary loudspeakers are selected to be smaller than the radiating loudspeaker and the number of auxiliary loudspeakers is such that, taken together, they form an equivalent single driver which is matched to the radiating loudspeaker to provide the desired frequency performance of the loudspeaker system. Since the auxiliary loudspeakers are smaller than the radiating loudspeaker, the baffle cutout in the external baffleboard is larger than the cutouts in the internal baffleboard.

Abstract: A nondirectional acoustic generator includes two acoustic generator units which are disposed facing each other as near as possible to the extent that diaphragms thereof do not become in contact with each other, drive units of the acoustic generator units being connected in series or in parallel to drive the acoustic generator units in phase and generate air compression sound waves which are radiated in the circumferential direction of the diaphragms.A speaker system includes a plurality of nondirectional acoustic generators coaxially disposed so as to align the centers of respective diaphragms and make the phases at sound generating areas coincident with each other.

Abstract: In a multi-channel audio circuit, a plurality of input signals are supplied to corresponding amplifiers each respectively connected to speakers, at least one of the input signals being inverted. The speaker connected to the amplifier receiving the inverted signal is connected at a polarity opposite that of the other speakers.

Abstract: A speaker system including a common input terminal for receiving an audio signal to be acoustically radiated; several speaker units; several digital filters connected between the common input terminal and the speaker units, and a filter coefficient for each of the digital filters. The speaker units are arranged linearly, in a matrix form or in a honeycomb form.

Abstract: There is disclosed herein a loudspeaker system of the dipole type, particularly for use in surround sound, reverberation and similar applications. An exemplary embodiment of the speaker system comprises a pair of woofers having dual voice coil drivers mounted on oppositely facing baffles (e.g., front and rear facing). Preferably, each baffle also includes a high frequency speaker mounted thereon. On a first baffle (e.g., front), both voice coils of the dual voice coil driver and the voice coil of the high frequency speaker are driven in-phase, and on the other baffle (e.g., rear), the second voice coil of the dual voice coil driver and the voice coil of the high frequency speaker are driven out-of-phase from those from the first baffle but in-phase with one another. The coils of the speakers are driven from suitable filter circuits.

Abstract: An acoustic imaging device includes a support structure and first and second drivers mounted on first and second faces respectively of the support structure. The first driver projects sound output in a first direction, and the second driver projects sound output in a second direction. The sound output of the second driver is out of phase with sound output of the first driver, and is at a level calculated to reduce substantially sound output from the first driver in a direction other than the first direction.

Abstract: A low sound loudspeaker system is constructed of an acoustic pipe extending from the back side of a loudspeaker unit, an air chamber provided at the front side of the loudspeaker unit, and a bass reflex port provided within the air chamber. The acoustic pipe communicates with the air chamber via the aperture of the acoustic pipe.

Abstract: A speaker system includes a left channel input and a right channel input for receiving left channel and right channel signals respectively, a left channel driver, a right channel driver, an (L-R) driver unit, and a (R-L) driver unit. The left channel driver is coupled to the left channel input, and the right channel driver is coupled to the right channel input. During a video mode of operation, the (L-R) driver unit and the (R-L) driver unit are each coupled to both the left channel input and the right channel input. The (L-R) driver unit and the (R-L) driver unit have structure arranged to passively differentially combine the signals on the inputs to provide (L-R) and (R-L) acoustic output signals respectively.

Abstract: An audio system includes a speaker unit having an opening in its front surface supporting a speaker and a diffuser with a reflecting surface detachably attached to the speaker unit and positioned opposite to the speaker and in front of the opening such that sound waves from the speaker are diffused by the reflecting surface of the diffuser to propagate radially. A multi-channel amplifier for driving the speaker includes a compensating circuit for correcting the output level and frequency characteristic of the system when the diffuser is attached.

Abstract: An improved efficiency loudspeaker that increases the accoustical output of the speaker by increasing its amplitude without increasing the power input to the speaker. This is accomplished by doubling the amplitude of displacement of a speaker diaphragm. The sound power of the speaker is thus increased by a factor of four. This is accomplished by utilizing a pair of voice coils which are reverse wired to each other so that both voice coils drive the diaphragm speaker. Thus, one voice coil pushes the diaphragm while the other pulls the diaphragm. This essentially doubles the acceleration of the diaphragm, therefore, doubling the velocity per unit time and thereby doubling the amplitude displacement per unit time. An even more efficient configuration is obtained by using two sets of these wired in parallel where sound power is increased 8 (eight) to 10 (ten) times.

Abstract: An improved dipole type characteristic loudspeaker system has a pair of loudspeakers (1 and 2) which are mounted on the front baffle board (4) and the back baffle board (5) of a console (3) and are connected to be driven in each-other opposite phase relation and have substantially the same acoustic characteristics in the medium and high frequency range but different acoustic characteristic in low frequency range; such loudspeaker system produces good surround-sound effect when used as back loudspeakers only with small number.

Abstract: An arrangement of divergently mounted acoustic transducers in a hemispherical air tight enclosure, the enclosure being sized with regard to the loading requirements of the acoustic transducers to produce a small size speaker system having an omnidirectional sound radiation pattern and a flat frequency response without the need of a crossover network. The hemispherical enclosure being comprised of six flat equal sided pentagonal plates, five triangular shaped flat gussets and a flat base plate all of which when assembled forms a half dodecahedron polyhedron shaped enclosure with a closed base, with the base serving as the enclosure mounting surface.

Abstract: According to the invention, a high-powered community alerting and warning device comprising a number of electromagnetic drivers is energized for tone generation by means of a rotary alternator that produces, when driven at a predetermined rotational speed, a sine-wave a.c. in the 400-800 Hz range. The alternator output is applied directly to the drivers, eliminating costly amplifier modules and energizing the drivers for better efficiency and reliability than an amplifier system. The alternator can be the output of a rotary frequency converter, or it can be driven by an engine or a separate electric motor.

Abstract: New loudspeaker driver configurations comprise positioning the high frequency driver between symmetrically located lower frequency drivers and providing in combination electrical or acoustical delay to the high frequency driver relative to the lower frequency drivers. The lower frequency drivers are located above and below at equal distances from the high frequency driver or, with more than two lower frequency drivers, symmetrically about the high frequency driver. The sound pressure level and phase response is substantially equivalent to co-axial drivers including suitable high frequency electric delay circuitry operating at similar power levels. The delay for the high frequency driver is electrical or electrical in combination with a geometrical delay. With a stereo pair of loudspeakers the high frequency driver may be offset from the vertical between the above and below low frequency drivers in an outboard direction of the stereo pair.

Abstract: A system for reproducing sound, particularly musical sound, giving enhanced pleasure to the listener. The system utilizes a pair of low frequency range speakers, a plurality of high frequency range speakers and may employ one or more mid frequency range speakers, all of which speakers are of conventional construction. These speakers are, however, disposed in a novel mechanical arrangement and electrically interconnected in a manner to emanate sound in essentially a non-directional manner. The listener thus perceives the sound to be emanating from the diemensional space surrounding the system, rather than from a single point or plane, and experiences the sound much as if he or she were in the same enclosure with live performers, rather than listening to a recording.

Abstract: The present invention includes a loudspeaker system in which sound radiation axes of two speakers in a single loudspeaker unit form an angle with respect to each other in a horizontal plane to increase the size of a listening area. The horizontal angle can be formed by orienting the sound axes of speakers in the loudspeaker unit at an angle in the range of 15 to 45 degrees from each other. The system also includes a phase adjustment system which adjusts the phase of the speakers in each loudspeaker unit so that the phase of the sound from each speaker in each loudspeaker unit is properly adjusted throughout the increased listening area to provide increased sound presence or spread.

Abstract: Sound reproduction apparatus comprising a pair of loudspeaker systems each including a plurality of loudspeakers for producing audio signals in response to respective electrical right (R) and left (L) stereophonic signals. Each system is mounted in an enclosure with sides and a gabled or V-shaped front portion characterized in having a pair of flat, vertical panels each joined to respective ones of the sides, the panels being joined at an intersecting angle to one another of about 90 to about 120 degrees at a forwardly projecting vertical ridge. Each system has a tweeter, woofer and mid-range speaker all connected for monophonically reproducing only a respective one of the stereophonic signals, and positioned in first ones of its panels. Each system also includes at least a second mid-range speaker connected for reproducing only a difference output between the stereophonic signals by using a dual voice coil driver, the second mid-range speaker being positioned in the other of its panels.

Abstract: A stereophonic baffle comprises a first transducer group (7 to 10) located along a first line and fed by a right signal of a Hi-Fi chain and a second group of transducers (11 and 15) located according to a second line, forming an angle with the first line, and fed by a left signal. The left and right signals feeding the groups of transducers (7 and 10 and 11 to 15) are in phase and the path (a to e) separating the active zones of the two associated transducers (6,11; 7,12; 8,13; 9,14; 10,15) is equal to an odd multiple of the half wave length of a frequency comprised between 300 and 1000 Hz thus creating an acoustic coupling for the frequency, between the two transducers. The coupling frequencies of the different transducer couples are different.

Abstract: For a good and efficient sound reproduction from a loudspeaker unit it is prescribed that two woofers are arranged back to back, one on a front plate of the unit and the other on an internal partion plate, whereby a front compartment of the unit operates as an effective bass reflection system, while a closed rear compartment contributes, via the rear loudspeaker, to improve the quality of the reproduced sound. The back to back arrangement of the two loudspeakers results in a non-vibrating unit.

Abstract: The single acoustic box with spatial effect for stereophonic musical reproduction systems, according to the invention, consists of an outer shell having at the top a loudspeaker for low-frequency sounds and on the lateral walls at least two loudspeakers for medium- and high-frequency sounds, positioned opposite to each other, and is equipped with a separating circuit having two inputs connectable to an amplifier of a stereophonic musical reproduction system and several outputs for low-frequency signals, unified and connected to the loudspeaker for low-frequency sounds and for high-frequency signals, divided between the two stereophonic reproduction channels, connected to two or more loudspeakers for medium - and high frequencies.The spatial effect is perceived by the listener due to the multiple reflections of the acoustic waves against the walls of the installation site.

Abstract: A loudspeaker system for use with a stereo system having right R and left L signal outputs, has a right main speaker and right sub-speaker, and a left main speaker and left sub-speaker. Inter-speaker cabling means, which connect to the R and L signal outputs, apply an R signal to the right main speaker and an R-L signal to the right sub-speaker, as well as an L signal to the left main speaker and an L-R signal to the left sub-speaker. The inter-speaker cabling means includes impedances for substantially attenuating the -R portion of the L-R signal and the -L portion of the R-L signal for signal frequencies below approximately 200 Hz.

Abstract: This speaker enclosure is of such design and structure, as to increase the input handling of speakers, enabling speakers rated at forty watts maximum handling, for example, to handle approximately eighty watts, which will facilitate the use of more of the sophisticated quality engineered into an excellent amplifier. Primarily, the enclosure employs a woofer, two mid-range speakers helped out by a ten inch horn, and two tweeters, and the speakers of the same frequency handling capacity, are wired in series. This arrangement covers the full audio frequency spectrum, and all of the speakers are crossed over by an adjustable cross-over.

Abstract: A sound reproduction system wherein two full range driver sets are employed to produce out-of-phase sound pressure lobes directed to either side of a listening area whereby the listening area is situated in the region of sound minimum pressure between drivers. The system decreases localization of speaker produced sound and enhances stereophonic and polyphonic effects.

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.

Abstract: A control system is provided with an alternating variable delay control arrangement for the control of a push-pull transducer system from an audio input signal source to achieve improved reproduction of high fidelity sound. The push-pull transducer system in one arrangement is of the type including two transducers coaxially disposed relative to each other with each transducer including a cone and an electrically actuated drive arrangement for each cone. The bases of the cones are in facing relationship and arranged to define a chamber therebetween. The control system supplies drive signals to the electrical drive arrangements of each transducer so as to drive the respective cones 180.degree. out of phase relative to each other. Further the control system selectively delays the supplied audio input signal to the electrically actuated drive arrangement corresponding to the cone that is being driven in the direction toward the apex of the cone.

Abstract: The disclosure relates to an audio signal reproduction system having one or more of the following features: (1) a loudspeaker having (a) a flat frequency response and (b) a predetermined power response; (2) two loudspeakers adapted to be positioned relative to one another so that they reproduce a stereophonic image substantially independent of the listener's position along a listening line spaced from the loudspeakers and nonintersecting a line extending between the two speakers; (3) an improved cross-over network having a substantially constant input impedance as a function of frequency; (4) a power sensor for sensing the power applied to a transducer so that audio signals are transmitted over a first signal path through the system when the sensed power is above a predetermined minimum level, and over a second path when the sensed power falls below the minimum level; (5) a power monitoring circuit to prevent a loudspeaker driver from being overdriven; and (6) a circuit for substantially balancing the signal

Abstract: An electrodynamic loudspeaker radiates sound in all directions and with a high output for a low and medium sound frequencies. It comprises two hemispherical movable diaphragms which are arranged on either side of a disc-shaped carrier part. The diaphragms are connected with the carrier part by flanges and constitute a pulsating sphere. In this sphere and connected in each case with one of the diaphragms are actuating units with permanent magnets and in each case, an oscillatory coil. Each oscillatory coil is connected to its respective diaphragm through stiff transition parts, preferably in the form of spherical shells. Openings are provided for an atmospheric pressure equalization between the interior and exterior of the breathing sphere.

Abstract: A loudspeaker system includes at least one electromagnetic loudspeaker assembly having a single vibratory coil form to which a vibratory diaphragm is attached. Two or more voice coils are wound on the vibratory coil form, each operating within a magnetic field. Electronic circuitry includes a signal conditioning network and a pair of amplifiers, one amplifier for each of the voice coils. The signal conditioning network, possibly preceded by a filter, is arranged to feed the respective amplifiers, the latter being coupled to their respective ones of the voice coils. D.C. currents provide forces in each of the voice coils, such that these forces are caused to oppose one another. The signal currents in the voice coils are such that the difference in the forces developed by the voice coils produce a vibratory motion of the voice coil form and the diaphragm attached thereto. A power supply is provided. A variable impedance circuit is connected between the power supply and the voice coils for adjusting the D.C.

Abstract: A multiple driver loudspeaker system comprises two angularly spaced rear rectangular baffles each nearly filled with four closely spaced full-range small loudspeakers with a port tube passing through the center of each rear baffle and the junction therebetween. A front baffle carries a small centrally located loudspeaker. The front loudspeaker is backed by a cavity that is vented through the port tube at the intersection between the rear baffles. Each of the remaining loudspeakers is backed by a cavity with the four cavities associated with each rear baffle being vented through the associated port tube through channels located at the front of each cavity. Two bullets are cantilevered from the front baffle rearward and essentially concentric within the respective centrally located ports. The volume of each of the nine cavities is substantially the same.