System and method for directionally radiating sound

• US 9,560,448 B2
• Filed: 07/19/2007
• Issued: 01/31/2017
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Hartung, Klaus
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): SUTHERS, DOUGLAS JOHN
• Application Number:
  US11/780,468
• Publication Number:
  US 20080273714A1
• Time in Patent Office: 3,484 Days
• Field of Search: 381/86, 381/89, 381/392, 381/304, 381/307, 381/95, 381/96
• US Class Current: 1/1
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: H04R 1/025 Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture
• CPC Class Codes: H04R 1/323 for loudspeakers H04R1/34 and H04R1/40 take precedence
• CPC Class Codes: H04R 2203/12 Beamforming aspects for stereophonic sound reproduction with loudspeaker arrays
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H04R 5/023 in a chair, pillow
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 2420/03 Application of parametric coding in stereophonic audio systems
• CPC Class Codes: H04S 3/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence

Abstract

An audio system for a vehicle has at least one source of audio signals. A respective directional loudspeaker array is mounted at each seat position and coupled to the at least one source. The at least one source includes a microphone that detects speech from an occupant of the first seat position. Processing circuitry receives signals from the microphone that correspond to the detect speech and drives each second respective loudspeaker array at the other seat positions to radiate acoustic energy corresponding to the detected speech. The processing circuitry processes magnitude and phase of the signals from the microphone to each second directional loudspeaker array so that each second directional loudspeaker array directionally radiates first acoustic energy to the seat position at which the second directional loudspeaker array is located and so that second acoustic energy radiated from the second directional array to the first seat position is less than the first acoustic energy according to a predetermined criteria.

Claims

1. An audio system for a vehicle having seat positions, said audio system comprising:

a respective loudspeaker array mounted at each of a plurality of seat positions in the vehicle;

a microphone mounted in the vehicle with respect to a first seat position of the plurality of seat positions so that the microphone detects speech from an occupant of the first seat position and outputs signals corresponding to the detected speech; and

processing circuitry between the microphone and each said respective loudspeaker array, wherein, for the first seat position, the processing circuitry receives the signals corresponding to the detected speech from the occupant of the first seat position and drives a respective loudspeaker array at each of one or more seat positions of the plurality of seat positions other than the first seat position to directionally radiate first acoustic energy corresponding to the detected speech to said one or more other seat position and to directionally radiate second acoustic energy to the first seat position so that the second acoustic energy is less than the first acoustic energy according to a predetermined criteria,

wherein each seat position of the plurality of seat positions is a said first seat position with respect to one or more seat positions other than that first seat position and the system has a plurality of said respective loudspeaker arrays mounted at each seat position of the plurality of seat positions, and wherein, at each said other seat position of the plurality of seat positions with respect to a respective said first seat position, the processing circuitry drives any said respective loudspeaker array with signals that correspond to the detected speech from the occupant of the respective first seat position only if the respective loudspeaker array is aligned between said other seat position and the respective first seat position.

2. A method of providing an audio system in a vehicle having a plurality of seat positions at which are disposed respective loudspeaker arrays configured to radiate acoustic energy to the seat positions at which the respective loudspeaker arrays are disposed and to isolate the other said seat positions of the plurality of seat positions from the acoustic energy, comprising the step of:

providing at least one microphone within the vehicle constructed and arranged to detect speech from an occupant of a first said seat position and output signals corresponding to the detected speech to the respective loudspeaker arrays at each of one or more said seat positions other than the first seat position, and excluding the first seat position, so that acoustic energy radiated by the respective loudspeaker array at said each other seat position corresponds to the detected speech;

providing a respective filter between the microphone and said respective loudspeaker array at said each other seat position, wherein the respective filter processes audio signals from the microphone to its respective loudspeaker array;

defining a respective cost function that compares acoustic energy in the vehicle radiated from said respective loudspeaker array at said each other seat position to the first seat position to acoustic energy in the vehicle radiated from the respective loudspeaker array at the other seat position to the other seat position;

calculating each said respective cost function; and

iteratively modifying each respective filter in response to its calculated cost function toward a predetermined criteria so that the acoustic energy radiated to the first seat position from the loudspeaker array at the other seat position corresponding to the respective filter is below a level that causes audio feedback at the first seat position.

3. The method as in claim 2, wherein each seat position of the plurality of seat positions is a said first seat position with respect to one or more seat positions other than that first seat position and wherein the audio system comprises a plurality of the at least one microphones constructed and arranged to respectively detect speech from an occupant of each seat position.

4. The method as in claim 2, wherein each respective filter provides unity gain at the second providing step.

5. A method of operating an audio system in a vehicle having a plurality of seat positions at which are disposed respective loudspeaker arrays configured to radiate acoustic energy to the seat positions at which the respective loudspeaker arrays are disposed and to isolate the other said seat positions of the plurality of seat positions from the acoustic energy, comprising the step of:

providing at least one microphone within the vehicle constructed and arranged to detect speech from an occupant of a first said seat position and output signals corresponding to the detected speech to the respective loudspeaker arrays at each of one or more said seat positions other than the first seat position, and excluding the first seat position, so that acoustic energy radiated by the respective loudspeaker array at said each other seat position corresponds to the detected speech; and

driving said respective loudspeaker array at said each of one or more other seat positions to directionally radiate first acoustic energy corresponding to the detected speech to said one or more other seat positions and to directionally radiate second acoustic energy to the first seat position that is optimized based on descent of a gradient of a cost function that compares the first acoustic energy to the second acoustic energy so that the second acoustic energy is below a level that causes audio feedback,

wherein the audio system comprises a filter between the at least one microphone and at least one speaker element in a said respective loudspeaker array at a said other seat position, wherein the filter processes the signals from the at least one microphone to the at least one speaker element of the respective loudspeaker array so that the filter contributes to a transfer function that relates the signals to the acoustic energy radiated to one or more of the plurality of seat positions from the at least one speaker element, and

implementing a set of coefficients to process the signals to the at least one speaker element so that a ratio of said transfer function between the signals and the acoustic energy radiated from the at least one speaker element to the first seat position and said transfer function between the signals and the acoustic energy radiated from the at least one speaker element to the other seat position meets a predetermined criteria for acoustic isolation.

6. An audio system for a vehicle having seat positions, said audio system comprising:

at least one source of audio signals;

a respective loudspeaker array mounted at each seat position of a plurality of the seat positions and coupled to the at least one source so that the audio signals drive the respective loudspeaker arrays to radiate acoustic energy;

wherein the at least one source comprises at least one microphone mounted in the vehicle with respect to a first seat position of the plurality of seat positions so that the at least one microphone detects speech from an occupant of the first seat position and outputs signals corresponding to the detected speech;

a filter between the at least one source and the respective loudspeaker array mounted at the first seat position that processes the audio signals that drive the respective loudspeaker array at the first seat position and is optimized based on descent of a gradient of a cost function that compares a magnitude of first acoustic energy radiated from the respective loudspeaker array at the first seat position to each other seat position of the plurality of seat positions to a magnitude of second acoustic energy radiated from the respective loudspeaker array at the first seat position to the first seat position so that the filter reduces the magnitude of the first acoustic energy compared to the magnitude of the second acoustic energy; and

processing circuitry between the at least one source and the respective loudspeaker arrays, wherein the processing circuitry receives the signals corresponding to the detected speech and outputs signals corresponding to the detected speech from the occupant of the first seat position to drive the respective loudspeaker array for each said other seat position and attenuates signals corresponding to the detected speech from the occupant of the first seat position that drive the respective loudspeaker array at the first seat position,

wherein each seat position of the plurality of seat positions is a said first seat position with respect to each seat position other than that first seat position and the system comprises a plurality of said respective loudspeaker arrays mounted at each first seat position, and wherein, at each second seat position of the plurality of seat positions, the processing circuitry drives any said respective loudspeaker array with signals that correspond to the detected speech from the occupant of a first seat position only if the respective loudspeaker array is aligned between the second seat position and the first seat position.

7. A method of operating an audio system in a vehicle having seat positions, comprising the steps of:

driving respective loudspeaker arrays mounted at a plurality of the seat positions so that the respective loudspeaker arrays radiate acoustic energy;

providing a plurality of microphones respectively mounted in the vehicle at the plurality of seat positions so that each microphone detects speech from an occupant of the seat position at which it is mounted and outputs signals corresponding to the detected speech; and

in response to a said microphone detecting speech at its seat position, driving a respective loudspeaker array at each other seat position of the plurality of seat positions to radiate acoustic energy corresponding to the detected speech, comprising processing signals that drive the respective loudspeaker arrays at the other seat positions and that correspond to the detected speech so that each respective loudspeaker array at each said other seat position directionally radiates first acoustic energy to its seat position and directionally radiates second acoustic energy to the microphone'"'"'s seat position and so that the second acoustic energy is less than the first acoustic energy according to a predetermined criteria,

wherein, where a plurality of said respective loudspeaker arrays are mounted at each said seat position, the second driving step comprises driving, at each said other seat position, a said respective loudspeaker array with signals that correspond to the detected speech from the occupant of the microphone'"'"'s seat position only if the respective loudspeaker array is aligned between the other seat position and the microphone'"'"'s seat position.

8. A method of operating an audio system in a vehicle having seat positions, comprising the steps of:

driving respective loudspeaker arrays mounted at a plurality of the seat positions so that the respective loudspeaker arrays radiate acoustic energy;

wherein at least one microphone is mounted in the vehicle with respect to a first seat position of the plurality of seat positions so that the at least one microphone detects speech from an occupant of the first said seat position and outputs signals corresponding to the detected speech;

driving the respective loudspeaker array at the first seat position to reduce a magnitude of acoustic energy radiated from the respective loudspeaker array at the first seat position to each seat position of the plurality of seat positions other than the first seat position, compared to a magnitude of acoustic energy radiated from the respective loudspeaker array at the first seat position to the first seat position; and

driving the respective loudspeaker array for each said other seat position with signals corresponding to the detected speech from the occupant of the first seat position and attenuating signals corresponding to the detected speech from the occupant of the first seat position that drive the respective loudspeaker array at the first seat position,

wherein each seat position of the plurality of seat positions is a said first seat position with respect to one or more seat positions other than that first seat position and wherein, where a plurality of said respective loudspeaker arrays are mounted at each seat position of the plurality of seat positions, the step of driving the respective loudspeaker array for each said other seat position comprises driving, at each said other seat position of the plurality of seat positions with respect to a respective said first seat position, any said respective loudspeaker array with signals that correspond to the detected speech from the occupant of the respective first seat position only if the respective loudspeaker array is aligned between said other seat position and the respective first seat position.

9. An audio system for a vehicle having seat positions, where the audio system is capable of outputting different audio content supplied by a plurality of audio sources to occupants of said seat positions simultaneously, the audio system constructed and arranged to provide acoustic isolation between different seat positions, said audio system comprising:

a respective at least one loudspeaker mounted at each seat position of a plurality of the seat positions;

respective microphones located at the plurality of seat positions so that each microphone detects speech from an occupant of its said seat position and outputs signals corresponding to the detected speech;

processing circuitry between the microphones and the respective loudspeakers that, in response to signals received from any said microphone corresponding to speech detected by the microphone at a first said seat position, either

drives the at least one loudspeaker at one or more said seat positions other than the first seat position, but not the at least one loudspeaker at the first seat position, with signals corresponding to the detected speech, or

drives the at least one loudspeaker at the one or more other said seat positions with signals corresponding to the detected speech and drives the at least one loudspeaker at the first seat position with signals corresponding to the detected speech that are attenuated with respect to the signals that drive the at least one loudspeaker at the one or more other seat positions;

wherein the respective loudspeaker mounted at each seat position of the plurality of seat positions is coupled to at least one of the audio sources so that audio signals from the at least one audio source drives the respective at least one loudspeaker to radiate acoustic energy; and

a filter between the at least one source and the respective at least one loudspeaker at the first seat position, wherein the filter processes the audio signals from the at least one source to at least one speaker element of the respective at least one loudspeaker at the first seat position so that the filter contributes to a transfer function that relates the audio signals from the at least one source to the acoustic energy radiated to one or more of the plurality of seat positions,

wherein the filter implements a set of coefficients to process the audio signals from the at least one source to the at least one speaker element so that a ratio of said transfer function between the audio signals from the at least one source to the at least one speaker element and the acoustic energy radiated by the at least one speaker element to at least one seat position of the plurality of seat positions other than the first seat position and said transfer function between the audio signals from the at least one source to the at least one speaker element and the acoustic energy radiated by the at least one speaker element to the first seat position meets a predetermined criteria for acoustic isolation so that the acoustic energy radiated by the at least one loudspeaker at the at least one other seat position to the first seat position is below a level that causes audio feedback, and

wherein the ratio is a ratio of said transfer function between the audio signals from the at least one source to the at least one speaker element and the acoustic energy radiated by the at least one speaker element to each said seat position of the plurality of seat positions other than the first seat position and said transfer function between the audio signals from the at least one source to the at least one speaker element and the output acoustic energy radiated by the at least one speaker element to the first seat position.