Abstract: A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of the enclosure to allow a back-wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.

Abstract: A loudspeaker system has a high frequency channel for driving a horn loaded high frequency transducer, and a low frequency channel for driving a low frequency transducer. A signal processing circuit is provided which has at least one first order and at least one second order cross-over circuit portion in the high channel and at least one first order and at least one second order cross-over circuit portion in the low frequency channel. These cross-over portions produce a cross-over frequency range for the loudspeaker system that is below the cut-off frequency of the horn. The signal processing circuit, including its cross-over circuit portions and in conjunction with the design of the expansion walls of the horn, extends vertical beamwidth control of the acoustic output of the loudspeaker system at the loudspeaker system's lower frequency range.

Abstract: An acoustically absorptive panel comprises a porous acoustical absorber having a planar configuration mounted on a support frame, an acoustically transparent front fabric stretch-mounted on the support frame and spaced from and in parallel alignment with the front face of the porous acoustical absorber and forming an airspace, the porous absorber, front fabric and forward air space acting as acoustical absorbing chamber capable of absorbing a greater range of sound frequencies than the porous acoustical absorber alone, the range of frequencies absorbed depending on the depth of the air space.

Abstract: A loudspeaker system has a plurality of relatively small transducer elements configured in a closely spaced transducer array such that their acoustic outputs combine to produce a focused beam of sound in front of the array that is substantially uniform about the beams radiation axis. The transducer array lies in a plane and has a perimeter that approximates a circle, and will have fill-factor with respect to a circle circumscribing the array of at least approximately 70%. In one variation of the loudspeaker system, the transducer array is constructed in smaller transducer array modules that are operatively fitted together to produce a larger array.

Abstract: A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of the enclosure to allow a back-wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.

Abstract: A loudspeaker system has a plurality of relatively small transducer elements configured in a closely spaced transducer array such that their acoustic outputs combine to produce a focused beam of sound in front of the array that is substantially uniform about the beams radiation axis. The transducer array lies in a plane and has a perimeter that approximates a circle, and will have fill-factor with respect to a circle circumscribing the array of at least approximately 70%. In one variation of the loudspeaker system, the transducer array is constructed in smaller transducer array modules that are operatively fitted together to produce a larger array.

Abstract: A loudspeaker horn (11) having a throat end (13) for receiving acoustic power from aligned acoustic power sources (41, 43, 45), an elongated throat (33), and a flared section (17) is provided with grating lobe mitigation fins (27, 29) that extend substantially parallel to the propagation axis of the horn from the throat end toward the mouth end of the horn's flared section. The length of the grating lobe mitigation fins is established in accordance with the degree of suppression of the grating lobes produced by the aligned acoustic power sources that is desired.

Abstract: A web hosted system and user interface in a client-server architecture permits audio designers to perform acoustic prediction calculations from a thin client computer. A client computer or other Internet connect device having a display screen is used by an audio professional to access via the Internet a host computer which performs acoustic prediction calculations and returns results of the calculations to the client. The results of the calculations are returned in the form of data visualizations, such as an area view showing visualizations of sound pressure levels within a defined space, an impulse view showing the time domain response at a defined location, and/or a frequency domain view showing the frequency response at a defined location. Calculations are performed based on user-defined inputs, such as speaker type and location, sent to the host computer from the client computer and based on retrieval of loudspeaker data from one or more databases accessible by the host computer.

Abstract: A web hosted system and method involving a client-server architecture permits audio designers to perform acoustic prediction calculations from a thin client computer. A client computer or other Internet connect device having a display screen is used by an audio professional to access via the Internet a host computer which performs acoustic prediction calculations and returns results of the calculations to the client. The results of the calculations are returned in the form of data visualizations, such as an area view showing visualizations of sound pressure levels within a defined space, an impulse view showing the time domain response at a defined location, and/or a frequency domain view showing the frequency response at a defined location. Calculations are performed based on user-defined inputs, such as speaker type and location, sent to the host computer from the client computer and based on retrieval of loudspeaker data from one or more databases accessible by the host computer.

Abstract: A loudspeaker horn (11) having a throat end (13) for receiving acoustic power from aligned acoustic power sources (41, 43, 45), an elongated throat (33), and a flared section (17) is provided with grating lobe mitigation fins (27, 29) that extend substantially parallel to the propagation axis of the horn from the throat end toward the mouth end of the horn's flared section. The length of the grating lobe mitigation fins is established in accordance with the degree of suppression of the grating lobes produced by the aligned acoustic power sources that is desired.

Abstract: A manifold for a horn loudspeaker has an input end having at least one input port for receiving acoustic power from at least one acoustic driver, and an output end for delivering acoustic power to the throat end of the horn. The output end of the manifold has at least two and suitably multiple output ports. An acoustic power waveguide is provided for each output port and connects each of the output ports to the input port of the manifold. Acoustic power received by the input port is divided between the acoustic waveguides such that it is delivered to the aligned output ports to simulate a line array of acoustic power sources.

Abstract: A manifold for a horn loudspeaker has an input end having at least one input port for receiving acoustic power from at least one acoustic driver, and an output end for delivering acoustic power to the throat end of the horn. The output end of the manifold has at least two and suitably multiple output ports. An acoustic power waveguide is provided for each output port and connects each of the output ports to the input port of the manifold. Acoustic power received by the input port is divided between the acoustic waveguides such that it is delivered to the aligned output ports to simulate a line array of acoustic power sources.

Abstract: An arrayable loudspeaker system having a horn-loaded high frequency compression driver and a low frequency cone driver radiates acoustic energy from a focal point in a polar radiation pattern having amplitude and phase and includes a signal conditioning circuit for amplitude equalization and phase correction. The horn of the system's horn-loaded compression driver is designed in cooperation with the signal conditioning circuit such that the focal point of the loudspeaker system is substantially frequency independent over the operating frequency range of the loudspeaker system and such that over this operating frequency range the loudspeaker's focal point remains substantially fixed in space. Any two or more of such loudspeaker systems can be arrayed by aligning them in respect to their frequency independent focal points and by rotating the loudspeakers about an axis passing through the aligned focal points to obtain a desired coverage.

Abstract: A system for processing outbound calls includes a system controller that controls the placement of an outbound call to a called number. The called number placed by the system controller has an associated country. The system includes a storage mechanism that stores multiple sets of call classification parameters. Each set of call classification parameters is associated with a particular country. A call classifier is coupled to the system controller and the storage mechanism. The call classifier can classify the result of the outbound call based on call classification parameters associated with the target country. The call classification parameters can include call progress tones associated with the country to which the outbound call was placed. The call classifier can also classify the answer status of the outbound call.

Abstract: A thermal inkjet printer is operated in a spray-mode by deliberately firing ink droplets from a printhead while the meniscus of the remaining ink in the printhead is settling down. Generally, the drops will not travel in a direction perpendicular to the printing surface. By calibrating the printhead, one can determine how many drops are needed to be fired within the boundaries of a pixel to achieve any given optical density. Drops may be fired at rates above 50 kHz, and, depending on the ink, above 70 kHz. Ink with a viscosity of 10 centi-Poise or less, and even 2 centi-Poise or less, may be used. When one is printing both text and non-text images on the same surface, a digital representation of an image to be printed is analyzed and divided into non-text image fields and text fields. Each non-text image field is printed on the printing surface by projecting the corresponding ink droplets in the spray-mode.

Abstract: A loudspeaker horn for use with an acoustical driver has a rectangular throat opening with a long dimension relative to the wavelength of the sound pressure waves generated within the high frequency range of the horn. A relatively short pre-load chamber corrects the phase of the sound pressure waves over the long dimension of the throat opening. The pre-load chamber provides control over the directivity of the horn and provides a uniform frequency response with minimal distortion.