JP5592566B2 - Active and passive directional acoustic radiation - Google Patents

Description

  This specification describes an audio system for a television receiver that uses a directional audio device.

  The following documents are known as prior art.

U.S. Pat.No. 5,870,484 U.S. Pat.No. 5,809,153 US Patent Application Publication No. 2009-0214066 A1 U.S. Patent Application No. 12 / 716,309 US Patent Application Publication No. 2009-0274329 A1

Boone et al., Design of a Highly Directional Endfire Loudspeaker Array, J. Audio Eng. Soc., Vol 57 van der Wal et al., Design of Logarithmically Spaced Constant Directivity-Directivity Transducer Arrays, J. Audio Eng. Soc., Vol. 44, No. 6, June 1996 Ward et al., Theory and design of broadband sensor arrays with frequency invariant far-field beam patterns, J. Acoust. Soc. Am. 97 (2), February 1995.

  In one aspect, the audio system includes at least a left channel, a right channel, and a center channel. The audio system includes a crossover network for dividing the left, right and center channels into low frequency content, mid frequency content and high frequency content, and mixed left, right and center channels. The omnidirectional acoustic device that radiates acoustic energy corresponding to the low frequency content of the channel and the acoustic energy corresponding to the middle frequency content of one of the left channel signal and right channel signal from the other direction Signal processing circuit and two or more acoustic drivers for radiating acoustic energy corresponding to the mid-frequency content of one of the left channel signal and the right channel signal A first directional array with a left channel signal and a right channel signal. The high frequency of one of the left channel signal and the right channel signal so that the acoustic energy corresponding to the high frequency content of one of the signals is emitted more in the lateral direction than in the other direction. A first passive directional device for emitting acoustic energy corresponding to the frequency content. The audio system is a second directional array for radiating acoustic energy, and the acoustic energy corresponding to the mid-range content of the other signal of the left channel signal and the right channel signal is from other directions. Signal processing circuit and two or more acoustic drivers for radiating acoustic energy corresponding to the mid-range content of the other of the left channel signal and the right channel signal A second directional array comprising: and the acoustic energy corresponding to the high frequency content of the other of the left channel signal and the right channel signal radiated more laterally than the other direction. A second receiver for radiating acoustic energy corresponding to the high frequency content of the other of the left channel signal and the right channel signal. Dynamic directional devices. The first directional array, the second directional array, the first passive directional device, and the second passive directional device can be mounted in a common housing. The common housing can be a television receiver cabinet. The first directional array and the second directional array may share at least one acoustic driver. The audio system may further include a third directional array that radiates acoustic energy, the third directional array having more acoustic energy corresponding to the central channel signal than the first directional array. For radiating acoustic energy corresponding to the mid-band content of the signal in the central channel so that more is emitted in a direction substantially orthogonal to the direction of radiation and the direction of more radiation of the second directional array A signal processing circuit and two or more acoustic drivers. The audio system may further include an omnidirectional high frequency acoustic device that emits high frequency content of the central channel. The omnidirectional high frequency device and the third directional array can be arranged on both sides of the television receiver screen in the vertical direction in the television receiver. At least two of the first directional array, the second directional array, and the third directional array may share at least one acoustic driver. The direction substantially orthogonal to the greater direction of radiation of the first directional array and the greater direction of radiation of the second directional array is substantially upward. The direction substantially perpendicular to the greater direction of radiation of the first directional array and the greater direction of radiation of the second directional array is the direction substantially toward the intended listening location. An omnidirectional device may comprise a waveguide. The waveguide can be mounted in a television receiver cabinet. At least two of the first directional array, the second directional array, and the third directional array share two or more acoustic drivers. The first directional array, the second directional array, and the third directional array may share two or more acoustic drivers. The audio system can be installed in the cabinet of the television receiver. The omnidirectional acoustic device, the first directional array, the second directional array, the third directional array, the first passive directional device, and the second passive directional device are each acoustic energy. Are radiated toward the surroundings, none of which can be in front of the television receiver. The first passive directional device may comprise a grooved tube passive directional acoustic device that includes an acoustic driver that is acoustically coupled to the tube and emits acoustic energy into the tube. The tube may include an elongated opening along at least a portion of the entire length of the tube and an acoustic resistance material in the opening that radiates pressure waves toward the periphery. Pressure waves are characterized by volume velocity. The tube, aperture, and acoustic resistance material are configured such that the volume velocity is substantially constant along the entire length of the tube.

  In another aspect, a method of operating an audio system comprising at least a left channel, a right channel, and a center channel includes omnidirectional acoustic energy corresponding to the mixed left channel, right channel, and center channel low frequency content. Radiating and from a first directional array comprising a signal processing circuit and two or more acoustic drivers, acoustic energy corresponding to the left channel mid-range content and acoustic energy corresponding to the left channel signal in the other direction From the second directional array with signal processing circuitry and two or more acoustic drivers, and acoustic energy corresponding to the mid-range content of the right channel The acoustic energy corresponding to the right channel signal is emitted more in the right direction than in other directions. From a third directional array comprising a signal processing circuit and two or more acoustic drivers, the acoustic energy corresponding to the mid-range content of the central channel, and the acoustic energy corresponding to the central channel signal. Radiating in a directional manner such that more is emitted in a direction substantially orthogonal to a greater direction of radiation of the first directional array and a greater direction of radiation of the second directional array; Radiating acoustic energy corresponding to the high frequency content of the left channel from the first passive directional device in a directional manner so that more acoustic energy is emitted in the left direction than in other directions; From the two passive directional devices, the acoustic energy corresponding to the high-frequency content of the right channel is higher in the right direction than in other directions. And a step of emitting a directional property as radiation. The method may further include irradiating the high frequency content of the center channel omnidirectionally. The step of radiating the high frequency content of the central channel in an omnidirectional manner is the step of radiating from the opposite side of the television receiver screen in the direction perpendicular to that of the central channel. May be included. Radiating acoustic energy omnidirectionally corresponding to the mixed left channel, right channel, and center channel low frequency content may include radiating from the waveguide. Radiating in an omnidirectional manner may include radiating from a waveguide mounted in a television receiver cabinet. Radiating directionally in a direction substantially orthogonal to a greater direction of radiation of the first directional array and a greater direction of radiation of the second directional array is radiating substantially upwards Can be included. Radiating directionally in a direction substantially orthogonal to the greater direction of radiation of the first directional array and the greater direction of radiation of the second directional array is substantially at the intended listening location. Radiating toward. Radiating directionally from the first directional array, radiating directionally from the second directional array, radiating directionally from the third directional array, and first passive Radiating directionally from the directional device and radiating directionally from the second passive directional device may include radiating from the television receiver cabinet. Radiating directionally from the first directional array, radiating directionally from the second directional array, radiating directionally from the third directional array, and first passive The step of radiating directionally from the directional device and the step of radiating directionally from the second passive directional device are steps of radiating from one of the side, bottom or top surfaces of the television receiver cabinet. Can be included.

  In another aspect, an audio system for a television receiver may include a television receiver cabinet and a grooved tube passive directional acoustic device that is acoustically coupled to the tube. And an acoustic driver that radiates acoustic energy into the tube. The tube may include an elongated opening along at least a portion of the entire length of the tube and an acoustic resistance material in the opening that radiates pressure waves toward the periphery. Pressure waves can be characterized by volume velocity. The tube, opening, and acoustic resistance material can be configured such that the volume velocity is substantially constant along the entire length of the tube. A passive directional acoustic device can be mounted in a television receiver cabinet to radiate sound waves laterally and directionally from the television receiver cabinet, and the tube is at least one of bent or curved. Can be one. The opening may be at least one bent or curved along its entire length. The opening can be on a curved surface or a curved surface. The television receiver cabinet can be narrowed back and forth, and the passive directional acoustic device has a curved wall or curved wall of the grooved tube passive directional acoustic device and the back of the television receiver cabinet and It can be mounted so as to be substantially parallel to the side wall. The opening may comprise two areas, a first area on the top surface of the tube and a second area on the side of the tube. The audio system for a television receiver according to claim 10.0, wherein the audio device may be for radiating left-channel or right-channel high-frequency content laterally from the television receiver. The passive directional acoustic device may be for emitting left channel content or right channel content above 2 kHz. The audio system may further include a directional array that radiates left channel or right channel mid-frequency content laterally from the television receiver. The audio system may further include a waveguide structure that radiates bus frequency content of the left channel or right channel, the other of the left channel or right channel, and the center channel. The cross-sectional area of the tube can decrease along the entire length of the tube.

  Other features, objects, and advantages will become apparent from the following detailed description when read in conjunction with the following drawings.

It is a top view of the audio | voice module attached in the television receiver. It is a front view of the audio | voice module attached in the television receiver. It is a top view of the audio | voice module attached in the television receiver. It is a front view of the audio | voice module attached in the television receiver. It is a top view of the audio | voice module attached in the television receiver. FIG. 6 is a front view of the audio module showing the position of the center channel speaker. 1 is a block diagram of an audio system. FIG. 3B is a block diagram illustrating an alternative configuration of some of the elements of the audio system of FIG. 3A. 1 is a diagram of a low frequency device of an audio system. 1 is an isometric view of an actual implementation of an audio system. It is a figure of an audio | voice module. FIG. 2 is a diagram of elements of a voice module used as a directional array. FIG. 2 is a diagram of elements of a voice module used as a directional array. FIG. 2 is a diagram of elements of a voice module used as a directional array. FIG. 2 is a diagram of elements of a voice module used as a directional array. 1 is a diagram of a passive directional acoustic device. FIG. 1 is a diagram of a passive directional acoustic device. FIG. FIG. 8 is an isometric view of an actual implementation of the passive directional device of FIGS. 7A and 7B. 1 is a diagram of a passive directional audio device installed in a television receiver. FIG.

  Elements of several figures of the drawings may be illustrated and described as individual elements in the block diagrams, and may also be referred to as “circuits”, unless otherwise indicated, these elements are analog circuits. , Digital circuitry, or one or a combination of one or more microprocessors that execute software instructions. The software instructions can include digital signal processing (DSP) instructions. The operations can be performed by analog circuitry or a microprocessor, which executes software that performs the mathematical or logical equivalent of the analog operation. Unless otherwise indicated, signal lines are implemented as individual analog or digital signal lines, single individual digital signal lines with appropriate signal processing to process separate streams of audio signals, or as elements of a wireless communication system. Good. Some of the processing may be illustrated in a block diagram. The functions performed in each block can be performed by one element or a plurality of elements, and can be separated in time. Elements that perform the functions of a block may be physically separated. An element may perform the function of more than one block. Unless otherwise indicated, audio and / or video signals may be encoded and transmitted in digital or analog form, and conventional digital-to-analog or analog-to-digital converters may not be shown in the figure . In order to simplify the expression, “radiating acoustic energy corresponding to the audio signal of channel x” may be referred to as “radiating channel x”. As used herein, a “directional array” refers to the combination of signal processing and the shape, arrangement, and configuration of two or more acoustic drivers so that radiation is greater in some directions than others. Refers to an array using Directional arrays include interference arrays such as those described in US Pat. No. 5,870,484 and US Pat. No. 5,809,153. As used herein, a “passive directional device” does not use any signal processing, but radiation with a wavelength that is large (e.g., × 2) compared to the diameter of the radiating element in some directions than in other directions. Refers to a device that uses only mechanical or physical components or devices to be large. Passive directional devices may include acoustic lenses, horns, dipole radiators or slot tube type directional devices shown below and in FIGS. 7A-7C and described in corresponding portions herein. .

  FIG. 1A shows a diagram of the audio module 10. The audio module 10 can be attached to or built in the television receiver 12. The audio module emits acoustic signals in several frequency ranges corresponding to an audio system including at least a left channel, a right channel, and a center channel.

  As shown, the left channel mid-range (LM) frequency sound is radiated by the directional array so that more acoustic energy is radiated in the left lateral direction than in the other direction relative to the listening location. Sound in the right channel mid-range (RM) frequency is radiated by the directional array so that more acoustic energy is radiated in the lateral right direction than in other directions, as shown.

  The left channel high frequency (LH) frequency sound is radiated by the passive directional device so that more acoustic energy is emitted in the lateral left direction than in the other direction, as shown. The sound at the right channel high frequency (RH) frequency is radiated by the passive directional device so that more acoustic energy is radiated in the lateral right direction than in the other direction, as shown.

  By radiating the left and right channels directionally and laterally, the radiation received by the listener is more indirect than the direct radiation or the left and right channels towards the listening location. Making more radiation become indirect radiation results in a more spacious sound image and allows the left and right channels to be radiated from a laterally intermediate device at the listening location.

  1B-1E illustrate different embodiments of the central channel radiation pattern.

  In FIGS. 1B and 1C, the sound of the central channel midrange (CM) frequency is radiated in the other direction with the energy radiated in a direction substantially orthogonal to the direction of maximum emission of the midband frequency sound of the left and right channels. It is emitted by the directional array so that it is more than what is done. The sound of the center channel high frequency (CH) frequency is such that the energy radiated in the direction substantially orthogonal to the direction of maximum emission of the sound of the middle frequency of the left and right channels is greater than that radiated in the other direction. Directional radiation by passive directional devices. In FIG. 1B, the direction of maximum emission of the mid-channel mid-range sound and the high-frequency sound is upward with respect to the listening location. In FIG. 1C, the direction of maximum emission of the mid-channel mid-frequency sound and the high-frequency sound is the direction toward the listening location. In other implementations, the direction of maximum emission of the central channel mid-frequency and high-frequency can be substantially downward. The direction of maximum emission of the sound of the central channel mid-frequency and the direction of maximum emission of the sound of the central channel high-frequency need not be the same direction. For example, mid-channel mid-frequency sounds may be emitted substantially upward, and mid-channel high-frequency sounds may be emitted substantially toward the listening location. The low frequency devices described below can be mounted in the television receiver cabinet 46.

  In FIGS. 1D and 1E, the sound of the mid-frequency in the center channel is radiated in the other direction with energy radiated in a direction substantially orthogonal to the direction of maximum emission of the sound of the mid-frequency of the left and right channels. Radiated by the directional array to be more. The sound of the center channel high frequency is radiated substantially omnidirectionally. In FIG. 1D, the direction of maximum emission of the center channel mid-range frequency is upward with respect to the listening location. In FIG. 1E, the direction of the maximum emission of the mid-channel mid-frequency sound is the direction toward the listening location.

  When implemented in a television receiver, the central channel high frequency acoustic device is in the vertical direction of the television receiver screen so that the sound image will be centered in the vertical direction on the television receiver screen. It can be placed on the opposite side of the central channel directional array. For example, as shown in FIG. 2, if the central channel directional array 44 is above the television receiver screen 52, the central channel high frequency acoustic device 45 may be placed below the television receiver screen. it can.

  FIG. 3A is a block diagram illustrating some signal processing elements of the audio module 10 of FIGS. The signal processing element of FIG. 3A is part of a three-way crossover system, which has input channels in three frequency bands (hereinafter referred to as the bus frequency band, mid-frequency band, and high-frequency band). None of these contain substantially any other frequency band. The signal processing element of FIG. 3A processes and radiates the three frequency bands separately.

  The left channel signal L, the right channel signal R, and the center channel signal C are mixed by the signal adder 29 and low-pass filtered by the low-pass filter 24 to obtain a composite low-frequency signal. The composite low frequency signal is radiated by a low frequency radiating device 26, such as a woofer or another acoustic device (including a low frequency enhancement element such as a port, waveguide, or passive radiator). Alternatively, as shown in FIG. 3B, the left channel signal, the right channel signal, and the center channel signal can be low pass filtered and then mixed before being emitted by the low frequency radiating device.

  In FIG. 3A, the left channel signal is bandpass filtered with a bandpass filter 28 and radiated directionally by the left channel array 30. The left channel signal is high pass filtered with a high pass filter 32 and radiated directionally (as indicated by the arrows extending from element 34) by a passive directional device 34.

  The right channel signal is bandpass filtered with a bandpass filter 28 and radiated directionally by the right channel array 38, as shown in FIGS. The right channel signal is high pass filtered by a high pass filter 32 and radiated directionally by a passive directional device 42.

  The center channel signal is bandpass filtered with a bandpass filter 28 and radiated directionally by the center channel array 44, as shown in FIGS. The center channel signal is high pass filtered with a high pass filter 32 and radiated directionally by a high frequency acoustic device 45 (as described above, this radiation is indicated by a dotted arrow extending from element 45. Can be directional or omnidirectional).

  In one embodiment, the low pass filter 24 has a corner frequency of 250 Hz, the band pass filter 28 has a pass band of 250 Hz to 2.5 kHz, and the high pass filter 32 has a corner frequency of 2 kHz.

  In one embodiment, the low frequency device 26 of FIG. 3A includes a waveguide structure as described in US Patent Application Publication No. 2009-0214066 A1, which is hereby incorporated by reference in its entirety. This waveguide structure is illustrated in FIG. 4A. An actual implementation of the low frequency device of FIG. 4A is shown in FIG. 4B. The reference numbers in FIG. 4B correspond to similarly numbered elements in FIG. 4A. The low frequency device may include a waveguide 412 that is driven by six 2.25 inch acoustic drivers 410A-410F mounted near the closed end 411 of the waveguide. Along the waveguide are acoustic volumes 422A and 422B acoustically coupled to the waveguide at locations 434A and 434B. The cross-sectional area of the waveguide increases at the open end 418. The embodiment of FIG. 4B is smaller in one dimension than the other two dimensions and can be conveniently sealed within a flat panel wide screen television receiver cabinet such as the cabinet 46 of the television receiver 12. .

  Directional arrays 30, 38 and 44 are shown in FIG. 3A with two acoustic drivers. In actual implementations, these arrays may have more than two acoustic drivers and may share a common acoustic driver. In one embodiment, left directional array 30, right directional array 38, and central directional array 44 are disclosed in Berardi et al., Filed Mar. 3, 2010, which is incorporated herein by reference in its entirety. It is implemented as a multi-element directional array such as that described in US patent application Ser. No. 12 / 716,309.

  FIG. 5 shows an acoustic module suitable for the left channel array 30, the right channel array 38 of FIG. 3A, and the central channel array 44 (all shown in FIG. 3A). The audio module 212 includes a plurality, seven in this embodiment, acoustic drivers 218-1 through 218-7. One of the acoustic drivers 218-4 is located near the top of the audio module, near the lateral center of the module. The three acoustic drivers 218-1 to 218-3 are located near the left end 220 of the audio module and are closely spaced apart so that the distances l1 ≠ l2, l2 ≠ l3, l1 ≠ l3 It is done. In addition, this interval is arranged so that l1 <l2 <l3. Similarly, the distances l6 ≠ l5, l5 ≠ l4, and l6 ≠ l4. In addition, the spacing may be arranged such that l6 <l5 <l4. In one embodiment, l1 = l6 = 55 mm, l2 = l5 = 110 mm, and l3 = l4 = 255 mm. Each of left channel array 30, right channel array 38, and center channel array 44 of FIG. 3A includes a subset of seven acoustic drivers 218-1 through 218-7.

  The directional radiation pattern in the mid-frequency band of FIGS. 1A-1E can be realized by an interferometric directional array consisting of a subset of acoustic drivers 218-1 through 218-7. Interferometric directional arrays are discussed in US Pat. No. 5,870,484 and US Pat. No. 5,809,153. At frequencies that an individual acoustic driver emits in a substantially omnidirectional direction (for example, a frequency that is more than twice the diameter of the acoustic driver's emitting surface), the radiation from each acoustic driver is Interfere with the radiation from the acoustic driver in a way that weakens or strengthens it. The effect of combining destructive and constructive interference is that the radiation in some directions is significantly smaller, for example -14 dB, compared to the maximum radiation in either direction. The direction in which the radiation is significantly smaller than the maximum radiation in either direction is sometimes referred to as the “null direction”. Making more of the radiation received by the listener indirect radiation is achieved by ensuring that the direction between the audio module and the listener is in the null direction, so that more radiation is delivered to the listener. Will be directed sideways.

  FIG. 6A is a diagram of the audio module 212, showing the configuration of the directional array of the audio module. The audio module is used to radiate the channels of the multi-channel audio signal source 222. Usually, a multi-channel audio signal source for use in a television receiver has at least left (L), right (R) and center (C) channels. In FIG. 6A, the left channel array 30 includes acoustic drivers 218-1, 218-2, 218-3, 218-4 and 218-5. The acoustic drivers 218-1 to 218-5 are coupled to the left channel signal source 238 by signal processing circuits 224-1 to 224-5, respectively, which are respectively transfer functions H1L (z) to H5L (z). The signal processing represented by The effects of the transfer functions H1L (z) -H5L (z) on the left channel audio signal may include one or more of transport shift, time delay, polarization, and others. The transfer functions H1L (z) to H5L (z) are typically implemented as digital filters, but may be implemented with equivalent analog devices.

  In operation, the left channel signal L modified by the transfer functions H1L (z) to H5L (z) is converted into acoustic energy by the acoustic drivers 218-1 to 218-5. The radiation from each acoustic driver interferes both destructively and reinforces to obtain the desired directional radiation pattern. To achieve a spacious stereo sound image, the left array 232 directs the radiation laterally toward the left boundary of the room, as indicated by arrow 213, to offset the radiation toward the listener. The use of a digital filter that applies a transfer function to create a directional interference array is described, for example, in Boone et al., Design of a Highly Directional Endfire Loudspeaker Array, J. Audio Eng. Soc., Vol 57. This concept is also discussed in terms of microphones in van der Wal et al., Design of Logarithmically Spaced Constant Directivity-Directivity Transducer Arrays, J. Audio Eng. Soc., Vol. 44, No. 6, June 1996 ( Also discussed in Ward et al., Theory and design of broadband sensor arrays with frequency invariant far-field beam patterns, J. Acoust. Soc. Am. 97 (2), February 1995. ing. Mathematically, the concept of a directional microphone array can generally be applied to speakers.

  Similarly, in FIG. 6B, the right channel array 38 includes acoustic drivers 218-3, 218-4, 218-5, 218-6 and 218-7. The acoustic drivers 218-3 to 218-7 are respectively coupled to the right channel signal source 240 and the signal processing circuits 224-3 to 224-7, which are respectively transfer functions H3R (z) to H7R (z). The signal processing represented by The effects of the transfer functions H3R (z) -H7R (z) may include one or more of transfer shift, time delay, inversion, and others. The transfer functions H3R (z) to H7R (z) are typically implemented as digital filters, but may be implemented with equivalent analog devices.

  In operation, the right channel signal R modified by the transfer functions H3R (z) to H7R (z) is converted into acoustic energy by the acoustic drivers 218-3 to 218-7. The radiation from each acoustic driver interferes both destructively and strengthens to produce the desired directional radiation pattern. In order to achieve a spacious stereo sound image, the right array 234 directs the radiation laterally toward the right boundary of the room, as indicated by arrow 215, to cancel the radiation toward the listener.

  In FIG. 6C, the central channel array 44 includes acoustic drivers 218-2, 218-3, 218-4, 218-5 and 218-6. The acoustic drivers 212-2 to 218-6 are coupled to the central channel signal source 242 by signal processing circuits 224-2 to 224-6, respectively, which are respectively transfer functions H2C (z) to H6C (z). The signal processing represented by The effects of the transfer functions H2C (z) -H6C (z) may include one or more of transfer shift, time delay, inversion, and others. The transfer functions H2C (z) to H6C (z) are typically implemented as digital filters, but may be implemented with equivalent analog devices.

  In operation, the center channel signal C modified by the transfer functions H2C (z) to H6C (z) is converted to acoustic energy by acoustic drivers 218-1 to 218-6. The radiation from each acoustic driver interferes both destructively and strengthens to produce the desired directional radiation pattern.

  An alternative configuration of the central channel array 44 is shown in FIG. 6D, which includes acoustic drivers 218-1, 218-3, 218-4, 218-5 and 218-7. The acoustic drivers 218-1, 218-3 to 218-5, and 218-7 are coupled to the central channel signal source 242 by signal processing circuits 224-1, 224-3 to 224-5, and 224-7, respectively. Each of these signal processing circuits performs signal processing represented by transfer functions H1C (z), H3C (z) to H5C (z), and H7C (z). The effects of transfer functions H1C (z), H3C (z) -H5C (z), and H7C (z) may include one or more of transfer shift, time delay, inversion, and others. The transfer functions H1C (z), H3C (z) -H5C (z), and H7C (z) are typically implemented as digital filters, but may be implemented with equivalent analog devices.

  In operation, the center channel signal C modified by the transfer functions H1C (z), H3C (z) -H5C (z), and H7C (z) is the acoustic driver 218-1, 218-3-218-5, and Converted to acoustic energy by 218-7. The radiation from each acoustic driver interferes both destructively and strengthens to produce the desired directional radiation pattern.

  The central channel array 44 of FIGS. 6C and 6D can direct the radiation upward, as indicated by arrow 217, and in some embodiments, the radiation is directed slightly back to the listener. Can be offset, or in other embodiments, the radiation can be directed toward the listening location.

  There may be other types of directional arrays suitable for use as directional arrays 30, 38, and 44. For example, each array may have only two acoustic drivers, provided that no acoustic driver is shared by multiple arrays.

  In one implementation, the left passive directional device 34 and right passive directional device 42 of FIG. 3A are implemented as illustrated in FIGS. 7A and 7B along with the actual example of FIG. 7C (no acoustic driver). Is done. The passive directional devices of FIGS. 7A and 7B operate according to the principles described in US Patent Application Publication No. 2009-0274329 A1, which is hereby incorporated by reference in its entirety.

  The passive directional device 310 of FIGS. 7A-7C includes a rectangular tube 316 with an acoustic driver 314 attached to one end. The tube is tapered from the end where the acoustic driver 314 is attached to the other end so that the cross-sectional area of the other end is substantially zero. A longitudinal groove 318 extending substantially the entire length of the tube is covered with an acoustic resistance material 320 such as a 165 × 800 plain twill woven unsintered stainless steel wire cloth. The dimensions and properties of the tube, groove and acoustic resistance material are set such that the volume velocity is substantially constant along the entire length of the tube.

  In the actual embodiment of FIG. 7C, one longitudinal section 354 of the rectangular tube is bent at a 45 degree angle with respect to the second section 352. The groove 318 in FIG. 7A is divided into two areas, one area 318A on the side 356 of the first area 354 of the tube and the second area of the groove 318B on the upper surface 358 of the second area 352 of the tube. It is divided into.

  The grooved tube directional speaker embodiment of FIG. 7B is particularly advantageous in some situations. FIG. 8 shows a curved or bent grooved directional radiator 110 in a television receiver cabinet 112. The dotted lines represent the side and back surfaces of the television receiver cabinet 112 viewed from above. For apparent or other reasons, the rear of the cabinet is narrowed inwardly, so that the rear of the cabinet is narrower than the front. Grooved tube directional radiators follow a portion of the cabinet where the bend or bend is generally narrower, i.e., the curved or inclined wall of the grooved tube directional radiator is substantially Are disposed in the cabinet so as to be parallel to the rear and side surfaces of the television receiver. The directional radiator can radiate through an opening on the side of the cabinet, which can be, for example, a louvered opening. The direction of the strongest radiation of this directional speaker is generally sideways and slightly forward as indicated by arrow 62, and this speaker is suitable for use as a passive directional device such as devices 32 and 42 of FIG. 3A. desirable.

  There may be other types of passive directional devices suitable as passive directional devices 32 and 42, such as horns, lenses, and the like.

  The use of passive directional devices for high frequency is advantageous because the desired directivity can be obtained without the need for a directional array. It is difficult to design a directional array that operates effectively at short wavelengths corresponding to high frequencies. At frequencies corresponding to wavelengths approaching the diameter of the radiating element, the radiating element itself can be directional.

  Numerous uses and deployments of the specific devices and techniques disclosed herein can be made without departing from the inventive concepts. As a result, the invention is to be construed as including all novel features and combinations of features disclosed herein, and is limited only by the spirit and scope of the appended claims. Should.

10 Voice module
12 Television receiver
24 Low pass filter
26 Low-frequency radiation device
28 Bandpass filter
29 Signal adder
30 Left channel array
32 high-pass filter
34 Left passive directional device
38 Right channel array
42 Passive directional device on the right
44 Central channel array
45 elements
52 Television receiver screen
62 Arrow
110 Curved or curved grooved directional radiator
112 Television receiver cabinet
212 audio module
213 arrow
215 arrow
217 arrow
218-1 to 218-7 Acoustic driver
220 Left end of audio module
222 Multi-channel audio source
224-1 to 224-7 Signal processing circuit
232 Left array
238 Left channel signal source
310 Passive Directional Device
314 Acoustic Driver
316 tubes
318 groove
318A 1 area of groove
318B Groove second area
320 Acoustic resistance material
352 2nd area
354 Longitudinal zone, first zone
356 side
358 Top view
410A ~ 410F 2.25 inch acoustic driver
412 Waveguide
418 Open end
422A, 422B acoustic volume
434A, 434B location
LM Left channel midrange
LH Left channel high range
RM Mid right channel
RH Right channel high range
CM Central channel midrange
CH Central channel high range
L Left channel
R right channel
C center channel
H1L (z) to H5L (z) transfer function
H3R (z) to H7R (z) transfer function
H2C (z) to H6C (z) transfer function
H1C (z), H3C (z) to H5C (z), H7C (z) transfer function

Claims (15)

A crossover network that divides the left, right, and center channels into low frequency content, mid frequency content, and high frequency content;
An omnidirectional acoustic device that emits acoustic energy corresponding to the mixed left channel, right channel and center channel low frequency content;
The left channel signal and the right channel signal are radiated in a lateral direction more than the other direction in the middle content of one of the left channel signal and the right channel signal. A first directional array comprising a signal processing circuit and two or more acoustic drivers for emitting acoustic energy corresponding to the mid-range content of the one of the signals of the channel;
The left channel signal and the left channel signal and the left channel signal and the right channel signal so that the acoustic energy corresponding to the high frequency content of the one signal is radiated more in the lateral direction than in the other direction. A first passive directional device for emitting acoustic energy corresponding to the high frequency content of the one of the right channel signals;
An audio system comprising: A second directional array for emitting acoustic energy, wherein the acoustic energy corresponding to the middle content of the other signal of the left channel signal and the right channel signal is transverse to the other direction; A signal processing circuit and two or more acoustic drivers for radiating acoustic energy corresponding to a mid-range content of the other of the left channel signal and the right channel signal so as to be radiated in a direction A second directional array comprising:
The left channel signal and the left channel signal and the left channel signal and the right channel signal such that the acoustic energy corresponding to the high frequency content of the other signal is radiated more in the lateral direction than in the other direction. A second passive directional device that emits acoustic energy corresponding to the high frequency content of the other signal of the right channel signal;
The audio system according to claim 1, further comprising:   The first directional array, the second directional array, the first passive directional device and the second passive directional device are mounted in a common housing. Voice system.   3. The audio system of claim 2, wherein the first directional array and the second directional array share at least one acoustic driver.   A third directional array that radiates acoustic energy, wherein the acoustic energy corresponding to the signal of the central channel is greater than the direction of radiation of the first directional array and of the second directional array; A signal processing circuit and two or more acoustic drivers for radiating acoustic energy corresponding to the mid-band content of the signal of the central channel so that more radiation is emitted in a direction substantially orthogonal to the direction of more radiation; The audio system of claim 1, further comprising a third directional array including.   6. The audio system of claim 5, further comprising an omnidirectional high frequency acoustic device that radiates high frequency content of the central channel.   6. The audio system according to claim 5, wherein at least two of the first directional array, the second directional array, and the third directional array share at least one acoustic driver. The audio system of claim 1, wherein the omnidirectional acoustic device comprises a waveguide.   9. The audio system of claim 8, wherein the waveguide is mounted in a television receiver cabinet.   9. The audio system of claim 8, wherein at least two of the first directional array, the second directional array, and the third directional array share two or more acoustic drivers. .   11. The audio system of claim 10, wherein the first directional array, the second directional array, and the third directional array share two or more acoustic drivers.   The audio system according to claim 1, wherein the audio system is installed in a cabinet of a television receiver.   The omnidirectional acoustic device, the first directional array, the second directional array, the third directional array, the first passive directional device, and the second passive directional 13. The audio system of claim 12, wherein each device has an outlet that radiates acoustic energy towards the surroundings, none of the outlets being in front of the television receiver. The first passive directional device is
A grooved tube passive directional acoustic device including an acoustic driver acoustically coupled to the tube and emitting acoustic energy into the tube;
The tube
An elongated opening along at least a portion of the total length of the tube, and an acoustic resistance material in the opening that radiates pressure waves toward the periphery;
The pressure wave is characterized by a volume velocity, and the tube, the opening, and the acoustic resistance material are configured such that the volume velocity is substantially constant along the entire length of the tube. The audio system according to 1. A television receiver cabinet,
The voice system according to any one of claims 1 to 14 ,
Provided with, audio system for a television receiver.

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