SOUND REPRODUCTION SYSTEM COMPRISING A LOUDSPEAKER ENCLOSURE WITH PORTS, AND ASSOCIATED PROCESSING CIRCUIT

• US 20100202619A1
• Filed: 07/21/2008
• Published: 08/12/2010
• Est. Priority Date: 07/26/2007
• Status: Active Grant

• Current Assignee: Nexo Co.
• Original Assignee: Nexo Co.
• Inventors: Vincenot, Eric
• Granted Patent: US 8,391,510 B2
• Time in Patent Office: Days
• US Class Current: 381/17
• CPC Class Codes: G10K 11/346 using phase variation
• CPC Class Codes: H04R 1/2826 for loudspeaker transducers
• CPC Class Codes: H04R 1/323 for loudspeakers H04R1/34 and H04R1/40 take precedence
• 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

Abstract

A sound reproduction system includes a loudspeaker enclosure that has a first loudspeaker and a second loudspeaker which are mounted on a surface of the enclosure. The first and second loudspeakers are respectively accommodated in a first space and a second space of the enclosure, the spaces being separated by a partition and being in communication with a first port and a second port, respectively. The first and second ports are located on opposite sides of the unit formed by the first and second loudspeakers. Processing elements are used for respectively applying a first and a second electric signal to the first and second loudspeaker, the first and second electric signals being generated from a single signal by differentiated phase processing that varies according to the frequency such that the first and second electric signals are offset relative to one another by a variable period of time which is proportionate to the acoustic distance between the first half of the loudspeaker enclosure including the first space, the first loudspeaker, and the first port, and the second half of the loudspeaker enclosure including the second space, the second loudspeaker, and the second port.

Claims

1. Sound reproduction system comprising:

a loudspeaker enclosure (2) provided with a first loudspeaker (10;

10′

;

10″

) and a second loudspeaker (11;

11′

;

11″

) mounted on one face of the enclosure,

the first loudspeaker and the second loudspeaker being respectively received in a first volume of the loudspeaker enclosure and in a second volume of the loudspeaker enclosure separated by a partition (4) and respectively discharging via a first port (12;

12′

;

12″

) and a second port (13;

13′

;

13″

), the first port and the second port being situated on respective opposite sides of the combination formed by the first loudspeaker and the second loudspeaker,

characterized by;

processing means (T) adapted to apply respectively to the first loudspeaker and to the second loudspeaker a first electrical signal and a second electrical signal obtained from the same signal by differentiated phase processing varying with frequency, such that the first electrical signal and the second electrical signal are offset by a varying time proportional to the acoustic distance between the first half-enclosure, including the first volume, the first loudspeaker and the first port, and the second half-enclosure, including the second volume, the second loudspeaker and the second port.

2. Sound reproduction system according to claim 1, wherein the differentiated processing is such that the first electrical signal and the second electrical signal are in phase opposition and offset by the varying time, said varying time corresponding to said acoustic distance.

3. Sound reproduction system according to claim 1, wherein the differentiated processing is such that the first electrical signal and the second electrical signal are in phase opposition and offset by the varying time, said varying time corresponding to one third of said acoustic distance.

4. Sound reproduction system according to claim 1, wherein the differentiated processing is such that the first electrical signal and the second electrical signal are in phase opposition and offset by the varying time, said varying time corresponding to three times said acoustic distance.

5. Sound reproduction system according to claim 1, wherein the differentiated processing is such that the first electrical signal and the second electrical signal are in phase and offset by a time corresponding to the acoustic distance.

6. Reproduction system according to claim 1, wherein the differentiated processing is such that the direction of maximum radiation efficiency is directed along the axis (Y) formed by the first loudspeaker and the second loudspeaker.

7. Reproduction system according to claim 1, wherein the axis formed by the first loudspeaker and the second loudspeaker is directed toward an audience area to be covered.

8. Reproduction system according to claim 1, wherein the processing means are adapted selectively to apply (K) an identical electrical signal to the first loudspeaker and to the second loudspeaker in a first mode of operation and the first electrical signal and the second electrical signal obtained by differentiated processing in a second mode of operation.

9. Reproduction system according to claim 1, wherein the first loudspeaker and the second loudspeaker are identical and wherein the first volume and the second volume are symmetrical with respect to the partition.

10. Reproduction system according to claim 1, wherein the first loudspeaker and the second loudspeaker are at a first distance (D_HP), the first port and the second port are at a second distance (D_EV) and the ratio of the second distance to the first distance is between 2 and 3 inclusive.

11. Reproduction system according to claim 10, wherein the ratio is between 2.2 and 2.5 inclusive.

12. Reproduction system according to claim 1, wherein the loudspeaker enclosure comprises a first pair of connecting points (20;

20′

;

20″

) electrically connected to the first loudspeaker and a second pair of connecting points (21;

21′

;

21″

) electrically connected to the second loudspeaker and wherein the processing means are adapted to apply respectively the first electrical signal to the first pair of connecting points and the second electrical signal to the second pair of connecting points.

13. Reproduction system according to claim 1, wherein the processing means comprise a filter (F) the phase transfer function of which is such that it generates a delay varying with frequency and substantially corresponding to the acoustic distance between the first half-enclosure, including the first volume, the first loudspeaker and the first port, and the second half-enclosure, including the second volume, the second loudspeaker and the second port.

14. Processing circuit adapted to apply a first electrical signal to a first loudspeaker mounted with a second loudspeaker on a wall of a loudspeaker enclosure having a first volume and a second volume separated by a partition, respectively receiving the first loudspeaker and the second loudspeaker, and each respectively communicating with a first port and a second port situated on respective opposite sides of the combination formed by the first loudspeaker and the second loudspeaker,

characterized by

processing means adapted to apply respectively to the first loudspeaker and to the second loudspeaker a first electrical signal and a second electrical signal obtained from the same signal by differentiated phase processing varying with frequency, such that the first electrical signal and the second electrical signal are offset by a varying time proportional to the acoustic distance between the first half-enclosure, including the first volume, the first loudspeaker and the first port, and the second half-enclosure, including the second volume, the second loudspeaker and the second port.

15. Processing circuit according to claim 14, wherein the processing means are adapted selectively to apply an identical electrical signal to the first loudspeaker and the second loudspeaker in a first operating mode and the first electrical signal and the second electrical signal obtained by differentiated processing in a second operating mode.

16. Processing circuit according to claim 14, wherein the processing means include a filter the phase transfer function of which is such that it generates a delay varying with frequency and substantially corresponding to the acoustic distance between the first half-enclosure, including the first volume, the first loudspeaker and the first port, and the second half-enclosure, including the second volume, the second loudspeaker and the second port.

17. Processing circuit according to claim 15, wherein the processing means include a filter the phase transfer function of which is such that it generates a delay varying with frequency and substantially corresponding to the acoustic distance between the first half-enclosure, including the first volume, the first loudspeaker and the first port, and the second half-enclosure, including the second volume, the second loudspeaker and the second port.