SOUND RADIATION PATTERN CONTROL

Abstract

Dual-array loudspeaker (100) comprising: a primary transducer (104) generating a primary radiation pattern (114) having a primary radiation center axis (112) in a primary plane (110) and a primary operating angle; and a secondary transducer (106) positioned on the primary plane (110) at a distance (d) from the primary transducer (104) and producing a secondary radiation pattern (116) having a secondary operating angle (124) that differs from a secondary radiation center axis (113), wherein the secondary radiation pattern (116) differs from the primary radiation pattern (114) on the primary plane (110), and wherein the radiation center axes (112, 113) of the primary and secondary transducers (104, 106) are generally parallel and spaced apart at a distance on the primary plane (110);wherein the secondary radiation pattern (116) modifies the primary radiation pattern (114) to produce a derived primary radiation pattern (118) which is different from the primary and secondary patterns (114, 116) on the primary plane (110) and has a derived radiation mean axis oriented at a derived operating angle which is different from both the primary and secondary radiation mean axes (112, 113) and from the primary operating angle.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 278,940, filed January 14, 2016, the disclosure of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates to acoustic radiation pattern control using various acoustic radiation devices. STATE OF THE ART

[0003] Loudspeakers that cover a room with sound must interface with listeners positioned throughout the room to provide uniform sound coverage. However, the room is typically asymmetrical from a speaker directivity perspective and not uniform in size. Loudspeakers at different locations in the room require different envelope shapes. For example, cinema surround speakers require a very different speaker geometry than monitor speakers. Furthermore, a side-wall surround speaker requires a very different room geometry than a rear-wall surround speaker. SUMMARY

[0004] According to one embodiment, a dual-array loudspeaker is provided. A primary transducer produces a primary radiation pattern on a primary plane. A secondary transducer is positioned on the primary plane at a distance from the primary transducer and produces a secondary radiation pattern that differs from the primary radiation pattern on the primary plane, the secondary radiation pattern modifying the primary radiation pattern to produce a derivative primary radiation pattern that differs from the primary and secondary patterns on the primary plane.

[0005] In a further embodiment, the radiation center axes of the primary and secondary transducers lie on the primary plane.

[0006] In another embodiment, the radiation center axes of the primary and secondary transducers are generally parallel and spaced apart at a distance on the primary plane.

[0007] In another embodiment, the primary plane is a vertical plane.

[0008] In another embodiment, the secondary transducer manipulates the primary radiation pattern at a primary level to achieve the derived primary radiation pattern.

[0009] In another embodiment, the primary and secondary transducers have a center frequency that is generally the same. The primary and secondary transducers are spaced apart by a distance 1.5 times greater than the center frequency of the primary and secondary transducers, the distance being measured between a radiation center axis of each of the primary and secondary transducers.

[0010] In another embodiment, the secondary transducer is operated at a sound output level that is lower than a primary sound output level.

[0011] In another embodiment, at least one of the primary and secondary transducers includes a first electronic filter mode and a second electronic filter mode. The derived primary radiation pattern comprises a first derived radiation pattern based on the first electronic filter mode and a second derived radiation pattern based on the second electronic filter mode.

[0012] In a further embodiment, the first electronic filter mode is a side mode and the second electronic filter mode is a back mode.

[0013] According to another embodiment, a dual-array loudspeaker is provided with a first transducer having a first radiation center axis and producing a first radiation pattern oriented at a first angle from the first radiation center axis. A second transducer having a second radiation center axis generally parallel to the first radiation center axis and producing a second radiation pattern oriented at a second angle from the second radiation center axis. A derivative radiation pattern is oriented at a derivative radiation angle that differs from the first and second angles when the first and second radiation patterns are combined.

[0014] In a further embodiment, the derived radiation angle is not parallel to the first and second radiation center axes.

[0015] In a further embodiment, the first converter has a first filter function and the second converter has a second filter function that is different from the first filter function.

[0016] According to another embodiment, a method is provided and includes generating a primary radiation pattern with a primary transducer. A secondary radiation pattern, different from the primary transducer, is generated with a second transducer. The primary radiation pattern is manipulated by the secondary radiation pattern to produce a derived primary radiation pattern that differs from the first and second radiation patterns.

[0017] In another embodiment, the method includes positioning the secondary transducer on the primary plane at a distance from the primary transducer, wherein the radiation center axes of the primary and secondary transducers lie on the primary plane.

[0018] In another embodiment, the method includes changing a filter function of at least one of the primary and secondary transducers. The derived radiation pattern is changed from a first mode to a second mode in response to changing the filter function.

[0019] In another embodiment, the derived primary radiation pattern is oriented at a derived angle that is different from a radiation angle of the primary and secondary transducers.

[0020] In another embodiment, the method includes operating the primary transducer at a primary sound output level that is higher than a secondary sound output level of the secondary transducer. List of characters Fig. 1 is a simplified, exemplary schematic side view of a loudspeaker according to one or more embodiments of the present disclosure. Fig. 2 is an exemplary cross-sectional side view of the loudspeaker according to one or more alternative embodiments of the present disclosure. Fig. 3 is a series of polar drawings illustrating exemplary individual acoustic radiation patterns of a first transducer on a vertical or primary plane at three different frequencies, according to one or more alternative embodiments of the present disclosure. Fig. 4 is a series of polar drawings illustrating exemplary individual acoustic radiation patterns of a second transducer on a vertical or primary plane at three different frequencies, according to one or more alternative embodiments of the present disclosure. Fig. 5 is a series of polar drawings illustrating exemplary individual acoustic radiation patterns derived from the individual patterns of the first and second transducers on the primary plane at three different frequencies in a side surround mode, according to one or more alternative embodiments of the present disclosure. Fig. 6 is a series of polar drawings illustrating exemplary acoustic radiation patterns derived from the individual patterns of the first and second transducers on the primary plane at three different frequencies in a rear surround mode, according to one or more alternative embodiments of the present disclosure. Fig. 7 is a simplified, exemplary block diagram of the loudspeaker from Fig. 1 according to one or more embodiments of the present disclosure. Fig. 8 is another simplified, exemplary block diagram of the loudspeaker from Fig. 1 according to one or more alternative embodiments of the present disclosure. DETAILED DESCRIPTION

[0021] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely examples of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0022] Professional loudspeakers must exhibit engineered sound radiation patterns. This is achieved in many ways, including the use of sonotrodes and numerous line array techniques. Therefore, pattern generation is a key engineering task in a loudspeaker's design. Actual room shapes require radiation patterns that are often impossible to achieve with individual devices. Individual devices exhibit patterns that are naturally smooth and rounded in shape, whereas room geometries require much sharper transitions, often in areas off the radiation axis, and achieving this with a single device is almost impossible.

[0023] Patterns with sharp transitions and unique shapes can be achieved when multiple sound devices with the same pattern are directed in the same direction. This is the basis of line-array behavior, where sound interference, which can be both constructive and destructive, is primarily determined by the sound time-of-flight differential of each device; that is, it is wavelength (frequency) dependent. State-of-the-art methods use arrays of the same devices (usually more than two) in the same space (i.e., "line arrays") or devices (similar and dissimilar) directed in different directions (i.e., "clusters") to create unique radiation patterns. In general, devices directed in the same direction intensify energy lobes, and those directed in different directions spread the energy lobe.

[0024] One or more embodiments of the present disclosure utilize two distinctly different radiating devices directed in the same direction to create a derived acoustic radiation pattern. The radiating devices may be distinctly different with respect to the acoustic radiation pattern each radiating device individually produces. The derived acoustic radiation pattern is unique to the individual acoustic sound radiation patterns of one of the two radiating devices. Manipulation of various key design variables allows for the derivation of a multitude of unique patterns in this manner using only the two radiating devices. This, in turn, allows for the creation of a sound radiation pattern that matches the unique geometry of a room.

[0025] Fig. 1 is a simplified, exemplary schematic side view of a loudspeaker 100 according to one or more embodiments of the present disclosure. The loudspeaker 100 may be a surround speaker, such as a side surround speaker or a rear surround speaker. According to one or more embodiments, the speaker may 100a professional cinema surround speaker. Professional cinema surround represents a unique case where the same sound characteristics are required from different locations within a cinema. Each speaker "sees" a distinctly different room geometry. Ideally, cinema surrounds require each surround speaker to cover the room identically. This requires a distinctly different radiation pattern from each speaker location, but with the same sound characteristic. Furthermore, each surround speaker must provide the same sound characteristic for the entire cinema. Although certain aspects of the present disclosure may be described with respect to professional cinema surrounds, the speaker described herein may be any type of speaker.

[0026] The loudspeaker 100 includes a housing 102 and a pair of radiation devices 104, such as a first transducer 104and a second converter 106 . According to one or more embodiments, the first converter 104 and the second converter 106High-frequency acoustic radiating devices. For example, a high-frequency device will operate in the audible range above 1,000 Hz. A device may also be considered a high-frequency device within the range between typically 2,000 Hz to 20,000 Hz, and has a corresponding wavelength in the range between approximately 6 inches to 0.6 inches. Wavelengths for medium-frequency and low-frequency transducers may be too large for meaningful pattern control due to package size limitations. For example, a medium-frequency device will operate in the range between 200 Hz to 2,000 Hz and has a corresponding wavelength of approximately 60 inches to 6 inches. However, aspects of the present disclosure may be used using medium-frequency and low-frequency transducers if not limited by package size. The pair of radiating devices 104 , 106may be the same or similar devices. Each radiation device 104 , 106 can be connected to a corresponding waveguide 108 be coupled.

[0027] While the speaker 100 with first and second radiation device 104 , 106 manipulates the sound radiation pattern to some extent in all directions, it is important to note that there is a primary operating level 110 As in Fig. 1, the first and second radiation devices 104 , 106 on one level 110 aligned so that the radiation center axes 112, 113 are on the plane 110 The radiation center axes 112 , 113 both the first and the second radiation device 104 , 106 are aligned in the same direction, so that the radiation axis 112 the first radiation device 104generally parallel to the radiation axis 113 the second radiation device 106 The pair of radiating devices 104 may be offset from each other on the primary plane. As shown in Fig. 1 and Fig. 2, the primary level 110 a vertical plane. Since the two radiation devices are distinctly different, this can apply in all directions. Therefore, the derived radiation pattern can include manipulations at all levels. However, it is understood that the primary plane 110 can offer the greatest degree of freedom.

[0028] In one embodiment, one of the radiation devices serves as the primary device and the other as the secondary device. For example, the first transducer 104 serve as a primary transducer that produces a primary radiation pattern 114 ( Fig. 3) and the second converter 106then serves as a secondary transducer to generate a secondary “manipulator” radiation pattern 116 ( Fig. 4). For example, the primary transducer may have an energy level of at least 3 dB, while the secondary transducer may have an energy level below the primary energy level. While the primary transducer produces a primary or dominant pattern at a higher energy level, the secondary transducer acts to manipulate the primary pattern to achieve a derivative radiation pattern.

[0029] As described above, the converter can 104 from the second converter 106by the sound radiation pattern it emits. Accordingly, the loudspeaker 100 can derive a unique sound radiation pattern by applying a technique that directs two dramatically different radiation patterns in the same direction. The secondary radiation pattern 114 can differ from the primary radiation pattern 116 although it may be directed in the same direction. In this way, the secondary radiation pattern 116 can be used to complement the primary radiation pattern 114 to modify the resulting unique sound radiation pattern 118 to generate ( Fig. 7- Fig. 8). Modifying the amount and timing of the secondary radiation pattern 116 with respect to the primary radiation pattern 114 can produce completely different results. The primary and secondary roles can be changed between the first transducer 104 and the second converter 106be swapped, which again leads to completely different results. Given the multitude of resulting sound radiation patterns 118 They typically involve shapes that cannot be achieved by individual radiation devices alone or by combinations of similar radiation patterns alone, and they can be quite useful in mapping asymmetric spatial geometries.

[0030] Fig. 2 is an example cross-sectional side view of the loudspeaker 120 according to another embodiment of the present disclosure. In addition to a pair of radiating devices 104, 106, the loudspeaker 120 include additional radiating devices that are not involved in the specific engineering of the acoustic radiation pattern produced by the pair of radiating devices 104 For example, the loudspeaker 120 a low-frequency converter 122include, for example, a woofer, to handle low-frequency audio in the audible sound spectrum. The low-frequency transducer 122 produced low frequency audio may have minimal, if any, influence on the sound radiation pattern shaping of the audio produced by the pair of radiating devices, the first transducer 104 and the second converter 106 , is emitted.

[0031] The speakers 100 , 120 of the present disclosure with two radiation devices 104, 106 can have several advantages. First, a radiation pattern from a secondary transducer 106 perform useful manipulations on a primary transducer 104, while sound output levels up to 20dB below the primary transducer 104 This applies particularly to the edge areas of the derived radiation pattern 118 where the primary radiation pattern 114can be naturally attenuated and the secondary radiation pattern 116 can be used to either enhance the area or the primary radiation pattern 114 to be weakened as required.

[0032] In one embodiment, the angular width of the radiation patterns 114 , 116 be different at the primary level with different forms. In this case, three very different form combinations can exist: ( 1 ) the narrow pattern can be dominant and the wide pattern can be used to modify the peripheral areas, either constructively or destructively; ( 2 ) the wide pattern can be dominant and the narrow pattern can be used to sharpen the pattern in a particular area; or ( 3Both radiation patterns can be used in tandem, resulting in a strong shape change, including beam shaping, anti-beam creation, and beam steering—all manipulated by electronic filtering. At some frequencies, such as low frequencies, neither pattern can be the primary pattern, and the first and second patterns can be used in tandem to achieve the derivative radiation pattern.

[0033] Any sound device is frequency dependent due to the fact that audible wavelengths vary by a factor of 1000. Loudspeaker designs require careful attention to frequency-dependent behavior. In this way, the loudspeaker 100 , 120 four operational frequency design regions, each approximately one octave wide. Fig. 3- Fig. 6 illustrates the frequency regions in which the signals from the dual-array transducers 104 , 106derived radiation patterns have the greatest effect.

[0034] The most critical of these areas can be the mid-frequency region 130 The center frequency region 130 may be the region with the most radiation pattern control and may be selected for the application. The wavelength of the center frequency (λ c ) can be an important dimension in loudspeaker design. For example, an approximate distance d ( Fig. 1) between the pair of radiation devices 104 be selected to be approximately 1.5 Ac, or one and a half times the center frequency wavelength. This can also establish an average dimension of each radiating device on the primary plane, also approximately 1.5 λ cThis could provide good pattern control from any device in the mid-frequency range, as well as a wide, solid operating angle for pattern control. In one example, the center frequency might be approximately 4,000 Hz, and the corresponding AC might be approximately 5 inches.

[0035] One octave below the center frequency lies a lower frequency region 132 where sound wavelengths become large enough that any radiating device begins to lose pattern control capacity. The loudspeaker 100 , 120 The present disclosure combats this phenomenon by changes in the filtering to each of the pair of radiating devices 104 , 106 . In the lower frequency region 132 it is possible that no radiation device 104 , 106as the primary, but both are used in tandem. In this way, the overall control frequency can be extended a full octave, while allowing a much more gradual and controlled transition away from the engineered radiation pattern. Frequency control can be further extended below the lower frequency region in the low-frequency device using appropriate system crossover design. 122 in the loudspeaker 120 be expanded.

[0036] One octave above the center frequency lies the first upper frequency region 134 , where frequencies show erratic behavior. In the upper frequency region 134the distance between the radiating devices is less complementary compared to the wavelength, and the interference between the devices is most destructive. However, in the first upper frequency region 134, each individual radiating device can exhibit its most precise pattern control. In this upper frequency region 134 As before, the electronic filtering can be modified to allow this change. The first upper frequency region 134 can typically define the fundamental radiation pattern for each device, since the primary transducer 104 can dominate in this region.

[0037] Two octaves above the center frequency is the second upper operating frequency region In the second upper frequency region, the interference patterns created are so dense (i.e. the wavelengths are very small) that the radiation pattern shape of the primary transducer 104 only marginally from the secondary converter106 Furthermore, the second upper frequency region is the location where each individual device may have its least effective output capacity. The combination of the pair of radiating devices 104 , 106 doubles the output capacity of the entire system in the second upper frequency region, which can reduce distortion and maintain good linearity in a region that normally suffers in this regard.

[0038] In contrast to line array loudspeakers, which include a plurality of radiation devices all having the same radiation patterns, the loudspeakers 100, 120 of the present disclosure use one radiation pattern to form another radiation pattern, i.e., the secondary pattern 116shape or manipulate the primary pattern 114 to achieve a resulting sound pattern that is distinct from both the primary and secondary patterns. This requires that each radiation pattern be distinctly different. Fig. 3- Fig. Figure 6 illustrates polar drawings of the dissimilar patterns of each of the transducers 104 , 106 which can be combined to achieve a derived sound pattern that differs from the first and second radiation patterns 114 , 116 differs.

[0039] Fig. 3 is a series of polar drawings illustrating exemplary individual sound radiation patterns 114 of the first or primary transducer 104on the vertical or primary plane 110 at three different frequencies, representing three usable main octaves. The series of polar drawings shows the frequency-dependent behavior of the first transducer 104. For example, the middle radiation shape shown is the radiation pattern 140 in the octave band of the design mid-frequency region 130 The left radiation form shows the radiation pattern 142 in the octave band of the upper frequency region 134 The right radiation form is the radiation pattern 144 in the octave band in the upper frequency region 134 As shown, the mean frequency radiation pattern 140 similar to the upper frequency radiation pattern 144 , where the upper frequency radiation pattern 144has more shape precision. The low frequency radiation pattern 144 shows a loss of pattern control. Therefore, it is necessary to show clearly different filtering for each octave band. It is noted that the first (primary) transducer 104 in the example in Fig. 3 is not a typical single device and is a dual-path radiator.

[0040] Fig. 4 is a series of polar drawings illustrating exemplary individual sound radiation patterns 116 of the second or secondary transducer 106 on the vertical or primary level 110 at three different frequencies representing usable main octaves. These drawings show a similar response for the second transducer 106 in the middle, lower and upper frequency region 130 , 132 , 134 as in Fig. 5, although the patterns are different. The second converter 106is an example of single-device patterns that typically have smooth and rounded shapes.

[0041] Also in Fig. 3 and Fig. 4 shows the radiation patterns 116 for the second transducer 106 different from the radiation patterns 114 for the first converter 104 For example, the radiation patterns 116 for the secondary converter 106 an operating pattern axis 148 which are generally at an operating angle 124 from the central radiation axis 112 of the secondary transducer 106. As shown in Fig. 4 illustrates the operating angle 124 about negative 15 degrees. As in Fig. 3, the radiation patterns 114 for the primary converter 104 an operating pattern axis 146 which are generally located along the central radiation axis 112 is aligned so that the operating angle 124is zero degrees.

[0042] Fig. 5 is a series of polar drawings showing exemplary sound radiation patterns 160 illustrate the individual patterns 114 , 116 of the first and second converter 104 , 106 at the primary level 110 at three different frequencies, which represent the three main usable octaves. In particular, Fig. 5 unique, derived sound radiation patterns 160 in middle, lower and upper frequencies 130 , 132 , 134 when the loudspeaker is in the side surround configuration mode. The derived sound radiation patterns 160 are formed in such a way that they are in an actual usage scenario in which the loudspeaker 100positioned along the upper side wall of a cinema and directed downwards towards the audience, while preventing a "hot spot" from occurring at locations close to the speaker 100 A hot spot can be an area that receives sound at too high a sound output level, or in other words, that is too loud at a particular frequency. In this case, the lower half of the pattern may be the most critical. The overall shape consistency is important with regard to the power response, while the shape of the lower half is most important for the uniformity of the direct field response. The consistency in this respect of the combination is greatly improved compared to the same criteria for single-device patterns. Furthermore, the derived operating radiation axis 172 of the derived sound radiation pattern 160 at a lateral operating angle 174which is aligned with at least one of the operating axes 146 , 148 of the pair of converters 104 , 106 differs.

[0043] Fig. Figure 6 is another series of polar drawings illustrating further sound radiation patterns 170 generated by the individual patterns 114 , 116 of the first and second converter 104 , 106 are derived at the primary level at three different frequencies, which represent the main usable octaves. In particular, Fig. 6 unique, derived sound radiation patterns 170 in middle, lower and upper frequencies 130 , 132 , 134 when the loudspeaker is in rear surround configuration mode. The derived sound radiation patterns 170 show even greater shape stability in all middle, lower and upper frequency regions 130 , 132, 134 . The derived acoustic radiation patterns 170 also show a strong downward bias, where the operating radiation axis 178 at a reverse operating angle 176 which was required to adequately map the audience seating plane, which leans downward and away from the loudspeaker positioned at a rear wall of the cinema. The derived operating radiation axis 178 of the derived sound radiation pattern 170 is aligned at a reverse operating angle of 176, which is located on both operating axes 146 , 148 of the pair of transducers 104, 106.

[0044] It should be noted that anti-bulge creation can be a very useful design feature and can be used in one or more embodiments to eliminate coverage "hot spots" that often occur in actual applications with individual devices. The loudspeaker 100, 120 of the present disclosure has the ability to create and manipulate anti-cules in strategic areas. For example, as in Fig. 7, reduces the derived radiation pattern 160 Sound from an area that could be a hot spot from only one transducer by creating an anti-bulb 190 .

[0045] In general, sound radiation devices directed in the same direction intensify the energy beam, and those directed in different directions spread the energy beam. The loudspeaker 100 , 120 according to the present disclosure has the ability to do both, depending on the basic design variables. As previously discussed, the design variables may include: ( 1 ) spacing and size of the pair of radiating devices 104, 106 relative to each other; ( 2) the individual sound radiation patterns 114, 116 of the devices 104 , 106 ; and ( 3 ) a position of each radiation device 104, 106 on the primary plane 110 These parameters can set the operating range of the resulting radiation pattern and its primary operating radiation axis. Based on this, electronic filtering can then be used to manipulate the resulting radiation pattern within this range. Changes to the above variables can directly affect the derived radiation pattern.

[0046] If the wavefronts in the primary and secondary radiation pattern 114 , 116If they are in phase, they add; if they are out of phase, they subtract. The addition and subtraction can be controlled by electronic filtering or even polarity inversion. This allows the edges of a pattern to be controlled where they would normally be impossible to control.

[0047] Electronic filtering can be the primary tool used to manipulate the mix between the primary radiation pattern and the secondary radiation pattern. The response can be so dramatic that even the simplest form of filtering (e.g., analog-passive) can produce good results, such as the derived radiation patterns. 160 , 170 With better filter precision, such as finite impulse response (FIR) filters, the derived radiation pattern shapes can become even more precise and consistent. With reference to Fig. Figure 7 illustrates a block diagram of the loudspeaker design. As shown, the loudspeaker 100 an audio signal input 202 to receive a single audio channel, such as a side surround audio signal or a rear surround audio signal.

[0048] The loudspeaker 100 be set for a typical room configuration. For example, in a professional cinema surround application, cinema shapes and sizes are relatively uniform. Accordingly, the loudspeaker 100 be designed for such applications. Since a side surround speaker can “see” the cinema differently than a rear surround speaker, the speaker can have a switch 204to selectively switch between a side surround configuration and a rear surround configuration or other configurations based on the sound requirements. Selecting the side surround configuration using the switch 204 can filter settings of a passive network 205 to create a unique radiation pattern sized and shaped for the auditorium from the perspective that a side surround speaker typically "sees" in a cinema or other common environment depending on the application. For example, as in Fig. 3, selecting the side surround configuration using the switch 204 the audio signal through a primary filter (side mode) 206 , which corresponds to the primary (first) converter 104 and a secondary filter (page mode) 208 , which is connected to the secondary (second) converter 106 corresponds to.

[0049] Likewise, selecting the rear surround configuration using the switch 204 Adjust filter settings to create a unique radiation pattern sized and shaped for the hall from the perspective typically "seen" by a rear surround speaker. In particular, selecting the rear surround configuration using the switch 204 the audio signal through a primary filter (reverse mode) 210 , which corresponds to the primary (first) converter 104, and a secondary filter (reverse mode) 212 , which is connected to the secondary (second) converter 106 The filter settings for the primary filters 206 , 210 may differ between the side mode and the back mode. Likewise, the filter settings for the secondary filters may 208 , 212 distinguish between side mode and back mode.

[0050] According to one or more embodiments, adjustment of the filter parameters may be possible in certain other loudspeaker applications for more specific room customization. This may be achieved by bi-amping the pair of radiating devices 104 and incorporating a digital signal processor (DSP). 214 , as in Fig. 4. The DSP 214 can be used to create a primary filter 216 and a secondary filter 218 specifically in the field.

[0051] While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terms used in this specification are descriptive rather than limiting, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Furthermore, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims

[1] Dual array loudspeaker, comprising: a primary transducer producing a primary radiation pattern at a primary level; and a secondary transducer positioned on the primary plane at a distance from the primary transducer and producing a secondary radiation pattern different from the primary radiation pattern on the primary plane; wherein the secondary radiation pattern modifies the primary radiation pattern to produce a derivative primary radiation pattern that is different from the primary and secondary patterns at the primary level. [2] The dual array loudspeaker of claim 1, wherein the first and second transducers include radiation center axes, the radiation center axes of the primary and secondary transducers being on the primary plane. [3] A dual array loudspeaker according to claim 2, wherein the radiation center axes of the primary and secondary transducers are generally parallel and spaced a distance apart on the primary plane. [4] The dual array loudspeaker of claim 2, wherein the secondary transducer manipulates the primary radiation pattern on a primary plane to achieve the derived primary radiation pattern oriented at an angle different from the radiation center axes of the primary and secondary transducers. [5] The dual array loudspeaker of claim 1, wherein the primary plane is a vertical plane. [6] The dual array loudspeaker of claim 1, wherein the primary and secondary transducers have a center frequency that is generally the same, and the distance at which the primary and secondary transducers are spaced is generally 1.5 times greater than the center frequency of the primary and secondary transducers, the distance being measured between a radiation center axis of the primary transducer and a radiation center axis of the secondary transducer. [7] The dual array loudspeaker of claim 1, wherein the secondary transducer is operated at a sound output level that is lower than a primary sound output level of the primary transducer. [8] The dual array loudspeaker of claim 1, wherein at least one of the primary and secondary transducers includes a first electronic filter mode and a second electronic filter mode, the derived primary radiation pattern comprising a first derived radiation pattern based on the first electronic filter mode and a second derived radiation pattern based on the second electronic filter mode. [9] The dual array loudspeaker of claim 8, wherein the first electronic filter mode is a side mode and the second electronic filter mode is a rear mode. [10] Dual array loudspeaker, comprising: a first transducer having a first radiation center axis and producing a first radiation pattern oriented at a first angle from the first radiation center axis; a second transducer having a second radiation center axis generally parallel to the first radiation center axis and producing a second radiation pattern oriented at a second angle from the second radiation center axis; and wherein a derived radiation pattern is oriented at a derived radiation angle that is different from the first and second angles when the first and second radiation patterns are combined. [11] The dual array loudspeaker of claim 10, wherein the derived radiation angle is not parallel to the first and second radiation center axes. [12] The dual array loudspeaker of claim 10, wherein the first transducer has a first filter function and the second transducer has a second filter function different from the first filter function. [13] A dual array loudspeaker according to claim 10, wherein the first and second radiation center axes lie on a primary plane. [14] The dual array loudspeaker of claim 13, wherein the first and second radiation center axes are generally parallel and spaced apart on the primary plane by a distance. [15] The dual array loudspeaker of claim 13, wherein the primary plane is a vertical plane. [16] Method comprising: Generating a primary radiation pattern with a primary transducer; Generating a secondary radiation pattern different from the primary transducer with a secondary transducer; and Manipulating the primary radiation pattern with the secondary radiation pattern to produce a derived primary radiation pattern that is different from the first and second radiation patterns. [17] The method of claim 16, further comprising positioning the secondary transducer at a distance from the primary transducer on a primary plane, wherein the radiation center axes of the primary and secondary transducers lie on the primary plane. [18] The method of claim 16, further comprising: changing a filter function of at least one of the primary and secondary converters; and Changing the derived primary radiation pattern from a first mode to a second mode. [19] The method of claim 16, wherein the derived primary radiation pattern is oriented at a derived angle that is different from a radiation angle of the primary and secondary transducers. [20] The method of claim 16, further comprising operating the primary transducer at a primary sound output level that is higher than a secondary sound output level of the secondary transducer.