Loudspeaker system

• US 4,860,363 A
• Filed: 03/18/1988
• Issued: 08/22/1989
• Est. Priority Date: 04/12/1985
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Suzuki, Hitoshi, Morita, Shigeru, Hara, Kozo, Koga, Shiro
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/171,224
• Time in Patent Office: 522 Days
• Field of Search: 381/89, 381/90, 381/24, 381/205, 381/188
• US Class Current: 381/89
• CPC Class Codes: H04R 1/323 for loudspeakers H04R1/34 and H04R1/40 take precedence
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers

Abstract

The present invention includes a loudspeaker system in which sound radiation axes of two speakers in a single loudspeaker unit form an angle with respect to each other in a horizontal plane to increase the size of a listening area. The horizontal angle can be formed by orienting the sound axes of speakers in the loudspeaker unit at an angle in the range of 15 to 45 degrees from each other. The system also includes a phase adjustment system which adjusts the phase of the speakers in each loudspeaker unit so that the phase of the sound from each speaker in each loudspeaker unit is properly adjusted throughout the increased listening area to provide increased sound presence or spread.

Claims

1. A loudspeaker unit, comprising:

a first speaker mounted in the unit, having a first sound projection axis and a sound reproduction bandwidth;

a second speaker mounted in the unit in a vertical direction with respect to said first speaker, having a sound reproduction bandwidth the same as said first speaker and a second sound projection axis, the first and second sound projection axes forming a projection angle therebetween in a horizontal direction; and

phase shifting means, operatively connected to said first speaker, for phase shifting the sound produced by said first speaker compared to the sound produced by said second speaker by a phase angle.

2. A loudspeaker as recited in claim 1, wherein the phase angle averages approximately ninety degrees.

3. A loudspeaker as recited in claim 2, wherein the horizontal projection angle is greater than or equal to 15 degrees and less than or equal to 45 degrees.

4. A loudspeaker system, comprising:

a left loudspeaker unit comprising;

a left enclosure having a front face;

a first speaker mounted in said left enclosure, having a first sound projection axis perpendicular to the front face of said left enclosure and a sound reproduction bandwidth; and

a second speaker mounted in said left enclosure in a vertical direction with respect to said first speaker, having a sound reproduction bandwidth the same as said first speaker and a second sound projection axis projecting rightward of the first sound projection axis by a horizontal angle;

a right loudspeaker unit spaced apart to the right from said left loudspeaker unit and comprising;

a right enclosure having a front face;

a third speaker mounted in said right enclosure, having a third sound projection axis perpendicular to the front face of said right enclosure and the same sound reproduction bandwidth as said first speaker; and

a fourth speaker mounted in said right enclosure in a vertical direction with respect to said third speaker, having a sound reproduction bandwidth the same as said first speaker and a fourth sound projection axis projecting leftward of the third sound projection axis by the horizontal angle;

left unit phase shift means, operatively connected to said second speaker, for phase shifting the sound from said second speaker compared with the sound from said first speaker by a phase angle; and

right unit phase shift means, operatively connected to said fourth speaker, for phase shifting sound from said fourth speaker compared with sound from said third speaker by the phase angle.

5. A loudspeaker system as recited in claim 4, wherein the phase angle average approximately ninety degrees.

6. A loudspeaker system as recited in claim 5, wherein high frequency sound is phase shifted more than low frequency sound.

7. A loudspeaker system, comprising:

a left loudspeaker unit comprising;

a left enclosure having a front face and only first and second speakers;

the first speaker mounted in said left enclosure, having a first sound projection axis perpendicular to the front face of said left enclosure and a sound reproduction bandwidth;

the second speaker mounted in said left enclosure in a vertical direction with respect to said first speaker, having a sound reproduction bandwidth the same as said first speaker and a second sound projection axis projecting horizontally and rightward of the first sound projection axis by a horizontal angle; and

left unit phase shift means, operatively connected to said second speaker, for phase shifting the sound from said second speaker compared with the sound from said first speaker by a phase angle; and

a right loudspeaker unit spaced apart to the right from said left loudspeaker unit and comprising;

a right enclosure having a front face and only third and fourth speakers;

the third speaker mounted in said right enclosure, having a third sound projection axis perpendicular to the front face of said right enclosure and the same sound reproduction bandwidth as said first speaker;

the fourth speaker mounted in said right enclosure in a vertical direction with respect to said third speaker, having a sound reproduction bandwidth the same as said first speaker and a fourth sound projection axis projecting horizontally and leftward of the third sound projection axis by the horizontal angle; and

right unit phase shift means, operatively connected to said fourth speaker, for phase shifting sound from said fourth speaker compared with sound from said third speaker by the phase angle.

8. A loudspeaker system as recited in claim 7, wherein the horizontal angle is greater than or equal to 15 degrees and less than or equal to 45 degrees.

9. A loudspeaker as recited in claim 7, wherein the phase angle equals La-Lb-sound wavelength/4 where La and Lb are the respective distances from the left and right loudspeaker units to the listener.