Loudspeaker device or system with controlled sound fields

• US 10,448,190 B2
• Filed: 11/24/2016
• Issued: 10/15/2019
• Est. Priority Date: 11/25/2015
• Status: Active Grant

• Current Assignee: Bang & Olufsen a/s
• Original Assignee: Bang & Olufsen a/s
• Inventors: Goller, Lars
• Primary Examiner(s): Kurr, Jason R
• Application Number:
  US15/778,824
• Publication Number:
  US 20180359593A1
• Time in Patent Office: 1,055 Days
• CPC Class Codes: H04R 1/24 Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges
• CPC Class Codes: H04R 1/2826 for loudspeaker transducers
• CPC Class Codes: H04R 1/2865 for loudspeaker transducers
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 3/008 in which the audio signals are in digital form, i.e. employing more than two discrete digital channels data reduction aspects thereof based on psychoacoustics G10L19/02
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence
• CPC Class Codes: H04S 7/303 Tracking of listener position or orientation

Abstract

The invention relates to a loudspeaker system or device configured such that the sound field generated by the system or device is controllable. The system or device comprises Left (16, 18; 41, 43) and Right (15, 17; 42, 46) loudspeaker arrangements configured for radiating at least mid and high frequency sounds to the surroundings (R) and for controlling the sound radiation pattern (21, 22, 23, 24, 25, 26) of the left and right loudspeaker arrangements, respectively, such that the beam width and/or direction of the main lobe of the directivity pattern for the respective Left and Right loudspeaker arrangements can be varied; and at least one signal processor configured to process the signals to be provided to the loudspeakers of the respective loudspeaker arrangements such that the directional characteristics of the loudspeakers in each respective arrangement can be varied. The system or device may further comprise a low frequency arrangement comprising an arrangement of one or more loudspeakers (11, 12, 13, 14, 37) mounted in an enclosure (1) and configured such that the loudspeakers radiates sound energy to the surroundings (R). The low frequency arrangement may be configured as a bass-reflex enclosure with a wide port region. By means of the system or device according to the invention, the resulting directional characteristic of the system or device can be adapted to numerous specific use situations, for instance to obtain a stereo-stabilizing effect on a perceived sound image.

Claims

1. A loudspeaker system configured such that a sound field generated by the loudspeaker system is controllable, comprising:

Left and Right loudspeaker arrangements configured for radiating at least mid and high frequency sounds to surroundings and for controlling a sound radiation pattern of the left and right loudspeaker arrangements, respectively, such that the beam width and/or direction of a main lobe of a directivity pattern for the respective Left and Right loudspeaker arrangements is variable;

at least one signal processor configured to process the signals to be provided to loudspeakers of the respective loudspeaker arrangements such that directional characteristics of the loudspeakers in each respective arrangement is variable;

wherein the resulting directional characteristic of the system can be adapted to specific use situations;

wherein the system further comprises a low frequency arrangement comprising an arrangement of one or more loudspeakers mounted in an enclosure and configured such that the loudspeakers radiate sound energy to the surroundings; and

wherein said enclosure comprises an inner house portion and an outer house portion, where the outer house portion partially surrounds the inner house portion, thereby forming a channel or gap between the inner and outer house portions, and where the inner house portion defines an inner space or cavity that is in acoustic communication via a portion with said channel or gap, the portion defining an inlet area to the channel or gap, and where said channel or gap is in acoustic communication with the surroundings via an outlet opening or port defining a port area and wherein said one or more loudspeakers are configured to radiate sound energy into said space or cavity, and wherein said port area is substantially larger than said inlet area, thereby reducing the volume velocity of the sound in the port area substantially relative to the volume velocity of the sound in the inlet area, wherein port noise is reduced and consequently the sound quality of the sound produced by the system at low frequencies is improved.

2. The loudspeaker system according to claim 1, wherein said Left loudspeaker arrangement comprises at least two loudspeakers provided in a front face of the Left loudspeaker arrangements, and wherein said Right loudspeaker arrangement comprises at least two loudspeakers provided in a front face of the Right loudspeaker arrangements, with at least one first loudspeaker in the respective arrangement having an axis substantially perpendicular to the front face of the respective arrangement and at least one second loudspeaker having an axis that is inclined an angle substantially different from the axis of the first loudspeaker.

3. A loudspeaker system according to claim 1, wherein said at least two loudspeakers in the Left loudspeaker arrangement are provided side by side in a lateral direction of the system, and wherein said at least two loudspeakers in the Right loudspeaker arrangement are provided side by side in the lateral direction of the system.

4. The loudspeaker system according to claim 1, wherein said enclosure is configured as a bass-reflex enclosure, which is provided with a bass-reflex sound channel having an inlet area configured to receive a sound energy from the loudspeakers in the low frequency arrangement and an exit area or a port area configured to provide the sound energy to the surroundings, wherein the port area is substantially larger than the inlet area, such that a volume velocity of sound generated by said loudspeakers in the channel is reduced in the port area relative to the inlet area leading to reduced port noise, wherein sound quality at low frequencies is improved, when high intensity low frequency sounds are reproduced by the low frequency arrangement.

5. The loudspeaker system according to claim 1, wherein the system is configured substantially symmetrically about a symmetry plane such that said Left and Right loudspeaker arrangements, respectively are positioned substantially symmetrically about the symmetry plane in the lateral direction of the system.

6. The loudspeaker system according to claim 5, wherein the system comprises at least one high frequency loudspeaker, at least one of which is located substantially at the symmetry plane of the system.

7. The loudspeaker system according to claim 1, wherein the loudspeaker system is provided with a control system configured to control the directional characteristics of the individual loudspeakers of the loudspeaker system, the control system comprising:

a plurality of digital signal processors, each of the digital signal processors having an input and an output, each of the digital signal processors configured to provide a processed version of an input signal at the output of the respective processor 9f the digital signal processors;

an input terminal for receiving the input signal;

output terminals for providing processed versions of the input signal to the respective loudspeakers;

an output selector configured to select processed outputs from one or more of the digital signal processors and to provide the selected outputs to predefined loudspeakers in the system.

8. The loudspeaker system according to claim 7, wherein said digital signal processors are configured to provide an output that is any combination of frequency weighted, time-delayed, phase-modified or gain-modified versions of the input to the respective one of the digital signal processors.

9. The loudspeaker system according to claim 1, wherein the respective directional characteristics (87, 89) of the Left (86) and Right (88) loudspeaker arrangements are optimized to provide a stabilizing effect on a stereo-image perceived by a listener at different positions (95, 97) in front of the loudspeaker system.

10. The loudspeaker system according to claim 9, wherein the direction of the main lobe of the directional characteristic of the Left loudspeaker arrangement (86) is inclined at a first angle relative to a line between the Left and Right loudspeaker arrangement and wherein the direction of the main lobe of the directional characteristic of the Right loudspeaker arrangement is inclined at a second angle relative to the line between the Left and Right loudspeaker arrangement, wherein the first and second angles are less than 90 degrees.

11. The loudspeaker system according to claim 10, wherein for listening points located in the lateral direction on a line in front of and substantially parallel to said line between the Left and Right loudspeaker arrangements the ratio between the magnitudes of the directional characteristic of the Right loudspeaker arrangement and the magnitude of the directional characteristic of the Left loudspeaker arrangement is substantially equal to a particular quantity multiplied by the ratio between the distance between the Right loudspeaker arrangement and the listening point and the distance between the Left loudspeaker arrangement and the listening point.

12. The loudspeaker system according to claim 11, wherein the particular quantity G is substantially constant within a predetermined frequency range.

13. A method for stabilizing a stereophonic sound image provided by a system according to claim 1, where the sound image is created by a Left loudspeaker arrangement and a Right loudspeaker arrangement placed a given distance apart along a line, where the respective directional characteristics of the Left and Right loudspeaker arrangements are chosen such that at a listening point in front of the loudspeaker arrangements at a given distance from the line, the ratio between the magnitude of the directional characteristics is substantially equal to a particular quantity multiplied by the ratio between the distance from the Left loudspeaker arrangement to the listening point L and the distance from the right loudspeaker arrangement to the listening point.

14. The method according to claim 13, wherein the particular quantity is substantially constant.

15. The method according to claim 13, wherein the particular quantity is substantially equal to unity.

16. A loudspeaker device configured such that a sound field generated by the loudspeaker device is controllable, comprising:

a housing provided with a front face extending substantially in a lateral direction;

a Left loudspeaker arrangement comprising at least two loudspeakers provided in the front face and configured to radiate sound energy into surroundings; and

a Right loudspeaker arrangement comprising at least two loudspeakers provided in the front face to the right of said left loudspeaker arrangement and configured to radiate sound energy into the surroundings;

wherein a first of said loudspeakers in the Left loudspeaker arrangement has a loudspeaker axis oriented substantially perpendicular the front face and a second of said loudspeakers in the Left loudspeaker arrangement has a loudspeaker axis extending at a first angle in the plane relative to the loudspeaker axis of the first loudspeaker that differs from zero; and

wherein a first of said loudspeakers in the Right loudspeaker arrangement has a loudspeaker axis oriented substantially perpendicular the front face and a second of said loudspeakers in the Right loudspeaker arrangement has a loudspeaker axis extending at a second angle in the plane relative to the loudspeaker axis of the first loudspeaker that differs from zero;

wherein the device further comprising one or more low frequency loudspeakers configured to radiate sound energy into the surroundings; and

wherein said housing comprises an inner house portion and an outer house portion, where the outer house portion partially surrounds the inner house portion thereby forming a channel or a gap between the inner and outer house portions, and where the inner house portion defines an inner space or a cavity that is in acoustic communication via a portion with said channel or gap, the portion defining an inlet area to the channel or the gap, and where said channel or the gap is in acoustic communication with the surroundings via an outlet opening or a port defining a port area, and wherein said one or more loudspeakers, are configured to radiate sound energy into said space or the cavity, and where said port area is substantially larger than said inlet area, thereby reducing the volume velocity of the sound in the port area substantially relative to the volume velocity of the sound in the inlet area, wherein port noise is reduced and consequently the sound quality of the sound produced by the system at low frequencies is improved when high intensity low frequency sounds are reproduced by the low frequency arrangement.

17. The loudspeaker device according to claim 16, wherein said low frequency loudspeakers are provided in said front face.

18. The loudspeaker device according to claim 16, wherein said housing has a generally elongated shape extending in a lateral direction on either side of a symmetry plane.

19. The loudspeaker device according to claim 18, wherein one of the loudspeakers in said Left loudspeaker arrangement has a loudspeaker axes that points in a direction towards said symmetry plane, and wherein one of the loudspeakers in said Right loudspeaker arrangement has a loudspeaker axes that points in a direction towards said symmetry plane.

20. The loudspeaker device according to claim 18, wherein the device is substantially symmetrical about said symmetry plane.

21. The loudspeaker device according to claim 16, wherein the device further comprises a high frequency loudspeaker provided in the front face.

22. The loudspeaker device according to claim 21, wherein said high frequency loudspeaker is provided substantially in said reference plane.

23. The loudspeaker device according to claim 16, wherein the loudspeaker device is provided with a control system configured to control the directional characteristics of the individual loudspeakers of the loudspeaker device, the control system comprising:

a plurality of digital signal processors each of the digital signal processors having an input and an output, each of the digital signal processors configured to provide a processed version of an input signal at the output of the respective one of the digital signal processors;

an input terminal for receiving the input signal;

output terminals for providing processed versions of the input signal to the respective loudspeakers;

an output selector configured to select processed outputs from one or more of the digital signal processors and to provide the selected outputs to predefined loudspeakers in the loudspeaker device.

24. The loudspeaker device according to claim 23, wherein said digital signal processors are configured to provide an output that is any combination of frequency weighted, time-delayed, phase-modified or gain-modified versions of the input to the respective one of the digital signal processors.

25. The loudspeaker device according to claim 16, wherein the respective directional characteristics of the Left and Right loudspeaker arrangements are optimized to provide a stabilizing effect on a stereo-image perceived by a listener at different positions in front of the loudspeaker device.

26. The loudspeaker device according to claim 25, wherein the direction of a main lobe of the directional characteristic of the Left loudspeaker arrangement is inclined at a first angle relative to a line between the Left and Right loudspeaker arrangement and wherein the direction of the main lobe of the directional characteristic of the Right loudspeaker arrangement is inclined at a second angle relative to the line between the Left and Right loudspeaker arrangement, wherein the first and second angles are less than 90 degrees.

27. The loudspeaker device according to claim 26, wherein for listening points located in the lateral direction on a line in front of and substantially parallel to said line between the Left and Right loudspeaker arrangements the ratio between the magnitudes of the directional characteristic of the Right loudspeaker arrangement and the magnitude of the directional characteristic of the Left loudspeaker arrangement is substantially equal to a particular quantity multiplied by the ratio between the distance between the Right loudspeaker arrangement and the listening point and the distance between the Left loudspeaker arrangement and the listening point.

28. The loudspeaker system according to claim 27, wherein the particular quantity is substantially constant within a predetermined frequency range.