System and method for directionally radiating sound

1. An audio system for a vehicle having a plurality of seat positions, wherein a forward direction is toward a forward end of the vehicle, a rearward direction is toward a rearward end of the vehicle, and side directions are transverse to the forward and rearward directions, and wherein for each of a plurality of first said seat positions there is a second said seat position that is proximate to the first seat position in a said side direction, said audio system comprising:

at each said first seat position,

a first directional loudspeaker array disposed at a seat at the first seat position at a position that is offset in a first said side direction from a first line extending in the forward and rearward directions and passing through an expected position of the head of a listener in the seat at the first seat position, wherein the second seat position is proximate to the first seat position in the first side direction; and

a second directional loudspeaker array disposed at the seat at a position that is offset in a second said side direction from the first line so that the first line is between the second array and the second seat position,

wherein each of the first directional loudspeaker array and the second directional loudspeaker array is driven by audio signals through audio signal processing circuitry to thereby radiate greater acoustic energy corresponding to the audio signals to the expected position of the head of a listener in the seat at the first seat position than to an expected position of the head of a listener at the second seat position,

wherein the first directional loudspeaker array comprises at least two acoustic drivers,

wherein the second directional loudspeaker array comprises at least three acoustic drivers,

wherein the first directional loudspeaker array and the second directional loudspeaker array each comprises a number of acoustic drivers that is different from the other,

wherein the second directional loudspeaker array is disposed adjacent a vehicle surface that is a near reflective surface with respect to the second directional loudspeaker array and the listener in the seat at the first seat position, and

wherein the second directional loudspeaker array includes an acoustic driver directed toward the near reflective surface.

2. The audio system as in claim 1 , wherein the first directional loudspeaker array has only two acoustic drivers.

3. The audio system as in claim 2 , wherein the second directional loudspeaker array has only three acoustic drivers.

4. The audio system as in claim 1 , wherein the first directional loudspeaker array and the second directional loudspeaker array are rearward of a second line that is perpendicular to the first line and that extends through the expected head position of the listener at the first seat position.

5. A method of arranging an audio system in a vehicle having a plurality of seat positions, wherein for each of a plurality of first said seat positions there is a second said seat position that is proximate to the first seat position, the method comprising the steps of:

providing at least one source of audio signals;

providing, at each seat position, a directional loudspeaker array so that the audio signals drive the directional loudspeaker array to radiate acoustic energy, wherein the directional loudspeaker array comprises a plurality of acoustic drivers;

processing the audio signals so that the directional loudspeaker array radiates greater acoustic energy corresponding to the audio signals to an expected position of the head of a listener at the first seat position than to an expected position of the head of a listener at the second seat position;

selecting a number of the acoustic drivers to include in the directional loudspeaker array, and an orientation of each said acoustic driver, based on at least an angle between a line from the directional loudspeaker array and a position to which it is desired to radiate acoustic energy and a line from the directional loudspeaker array and a position to which it is desired to reduce radiation of acoustic energy, and distance between the directional loudspeaker array and the position to which it is desired to radiate acoustic energy.

6. A method of arranging an audio system for a vehicle having a plurality of seat positions, wherein a forward direction is toward a forward end of the vehicle, a rearward direction is toward a rearward end of the vehicle, and side directions are transverse to the forward and rearward directions, and wherein for each of a plurality of first said seat positions there is a second said seat position that is proximate to the first seat position in a said side direction, said method comprising the steps of:

at each said first seat position,

disposing a first directional loudspeaker array at a seat at the first seat position at a position that is offset in a first said side direction from a first line extending in the forward and rearward directions and passing through an expected position of the head of a listener in the seat at the first seat position, wherein the second seat position is proximate to the first seat position in the first side direction, and

disposing a second directional loudspeaker array at the seat at a position that is offset in a second said side direction from the first line so that the first line is between the second array and the second seat position; and

identifying at least one vehicle surface that is a near reflective surface with respect to the second directional loudspeaker array and the listener at the first seat position,

wherein each of the first directional loudspeaker array and the second directional loudspeaker array is driven by audio signals through audio signal processing circuitry to thereby radiate greater acoustic energy corresponding to the audio signals to the expected position of the head of a listener in the seat at the first seat position than to an expected position of the head of a listener at the second seat position,

wherein the first directional loudspeaker array comprises at least two acoustic drivers,

wherein the second directional loudspeaker array comprises at least three acoustic drivers,

wherein the first directional loudspeaker array and the second directional loudspeaker array each comprises a number of acoustic drivers that is different from the other, and

wherein the second directional loudspeaker array includes an acoustic driver directed toward the near reflective surface.

7. The method as in claim 6 , wherein the first directional loudspeaker array has only two acoustic drivers.

8. The method as in claim 7 , wherein the second directional loudspeaker array has only three acoustic drivers.

9. The method as in claim 6 , wherein the first directional loudspeaker array and the second directional loudspeaker array are rearward of a second line that is perpendicular to the first line and that extends through the expected head position of the listener at the first seat position.