Array speaker system

• US 7,519,187 B2
• Filed: 06/02/2004
• Issued: 04/14/2009
• Est. Priority Date: 06/02/2003
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Konagai, Yusuke
• Primary Examiner(s): Chin; Vivian
• Assistant Examiner(s): Monikang; George C
• Application Number:
  US10/558,947
• Publication Number:
  US 20070030977A1
• Time in Patent Office: 1,777 Days
• Field of Search: 381/96, 381/97, 381/95, 381/89, 381/77, 381/80, 381/82, 381/102, 381/92, 381/98
• US Class Current: 381/98
• CPC Class Codes: H04R 2205/022 Plurality of transducers corresponding to a plurality of sound channels in each earpiece of headphones or in a single enclosure
• CPC Class Codes: H04R 2430/20 Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic H04R2203/12 takes precedence
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04S 3/00 Systems employing more than two channels, e.g. quadraphonic H04S5/00, H04S7/00 take precedence

Abstract

Input audio signals are divided into low-frequency components and high-frequency components, both of which are subjected to delay processing in correspondence with desired positions of focal points with respect to speaker units respectively. Delayed low-frequency components are further subjected to weighting using a first window function. Delayed high-frequency components are subjected to weighting using a second window function (e.g., a Hamming window function). Weighted high-frequency components and weighted low-frequency components are added together with respect to the speaker units, which are thus driven respectively. The first window function applied to low-frequency components is made moderate in weighting in comparison with the second window function applied to high-frequency components; thus, it is possible to reduce differences of sound directivities between low-frequency components and high-frequency components of audio signals.

Claims

1. An array speaker system comprising:

an array speaker having a plurality of speaker units arranged in an array, including at least one center speaker unit and a plurality of peripheral speaker units, for emitting audio signal beams with predetermined time differences therebetween so as to control sound directivity; and

a control circuit that imparts a first weight to the center speaker unit with respect to high-frequency signal components of input audio signals, and second weights to the peripheral speaker units in the array speaker with respect to the high-frequency signal components of the input audio signals,

wherein the first weight is relatively higher than the second weights,

wherein the control circuit imparts a third weight to the center speaker unit with respect to low-frequency signal components of the input audio signals, and imparts fourth weights to the peripheral speaker units with respect to the low-frequency signal components of the input audio signals, and

wherein differences between the third and fourth weights, which are imparted to the center speaker unit and the peripheral speaker units with respect to the low-frequency signal components, are relatively smaller than the differences between the first and second weights, which are imparted to the center speaker unit and the peripheral speaker units with respect to the high-frequency signal components.

4. The array speaker system according to claim 1, wherein the third and fourth weights are the same.

2. An array speaker system comprising:

an array speaker having a plurality of speaker units arranged in an array, including a plurality of center speaker units and a plurality of peripheral speaker units, for emitting audio signal beams with predetermined time differences therebetween so as to control sound directivity,

a control circuit that imparts first weights to the center speaker unit with respect to high-frequency signal components of input audio signals, and second weights to the peripheral speaker units with respect to the high-frequency signal components of the input audio signals,

wherein the first weights are relatively larger than the second weights, and

wherein the control circuit imparts, with respect to low-frequency signal components of the input audio signals, a same weight to all of the center speaker units and all of the peripheral speaker units in the array speaker.

3. An array speaker system comprising:

an array speaker having a plurality of speaker units arranged in an array, including a plurality of center speaker units and a plurality of peripheral speaker units, for emitting audio signal beams with predetermined time differences therebetween so as to control sound directivity;

a circuit that divides the input audio signals into three frequency bands, including low-frequency signal components, intermediate-frequency signal components, and high-frequency signal components; and

a control circuit that imparts first weights to the center speaker units with respect to the high-frequency signal components of input audio signals, and second weights to the peripheral speaker units in the array speaker with respect to the high-frequency signal components of the input audio signals,

wherein the first weights are relatively larger than the second weights,

wherein the control circuit imparts third weights to the center speaker units with respect to the intermediate-frequency signal components of the input audio signals, and fourth weights to the peripheral speaker units with respect to the intermediate-frequency signal components of the input audio signals,

wherein differences between the third and fourth weights, which are imparted to the center speaker units and the peripheral speaker units with respect to the intermediate-frequency signal components, are relatively smaller than the differences between the first and second weights, which are imparted to the center speaker units and the peripheral speaker units with respect to the high-frequency signal components, and

wherein the control circuit imparts, with respect to low-frequency signal components of the input audio signals, a same weight to all the center speaker units and the peripheral speaker units in the array speaker without applying the time differences to the speaker units.

5. The array speaker system according to claim 3, wherein the third and fourth weights are the same.