Bass reproduction speaker apparatus

• US 5,588,065 A
• Filed: 05/23/1995
• Issued: 12/24/1996
• Est. Priority Date: 12/20/1991
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Iimura, Katsuhiko, Kageyama, Satoshi, Tanaka, Shoji
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US08/447,429
• Time in Patent Office: 581 Days
• Field of Search: 381/96, 381/59
• US Class Current: 381/96
• CPC Class Codes: H04R 1/2834 for loudspeaker transducers
• CPC Class Codes: H04R 1/2842 for loudspeaker transducers
• CPC Class Codes: H04R 3/002 Damping circuit arrangements for transducers, e.g. motional feedback circuits

Abstract

A bass reproduction speaker apparatus of the present invention includes: a cabinet with an opening, having a division member inside thereof; a speaker unit disposed at the division member; a passive radiator disposed in the opening; an amplifier for driving the speaker unit; a detector for detecting a vibration of a moving system of the speaker unit; and a feedback circuit for feeding back an output signal from the detector to the amplifier.

Claims

1. A bass reproduction speaker apparatus, comprising:

a cabinet with an opening, having a division member inside thereof;

a speaker unit disposed at the division member;

a passive radiator disposed in the opening;

an amplifying means for driving the speaker unit;

a detection means for detecting motion of a moving system of the speaker unit; and

a feedback means for feeding back an output signal from the detection means to the amplifying means, the feedback means conducting both a velocity-type motion feedback and an acceleration-type motion feedback simultaneously over the same frequency band such that the acceleration-type motion feedback substantially aligns a height of peaks in an output sound pressure level versus frequency response of the speaker apparatus at two resonance frequencies in a low frequency range with each other, and the velocity-type motion feedback suppresses the peaks to obtain a substantially flat output sound pressure level over a wide range of low frequencies.

2. A bass reproduction speaker apparatus according to claim 1, wherein the detection means is a sensor disposed at the moving system.

3. A bass reproduction speaker apparatus according to claim 1, wherein the detection means is a microphone.

4. A bass reproduction speaker apparatus according to claim 1, wherein the detection means is a detection circuit disposed between the amplifying means and the speaker unit.

5. A bass reproduction speaker apparatus according to claim 1, further comprising a second detection means for detecting a vibration of a moving system of the passive radiator;

and a second feedback means for feeding back a detection signal from the second detection means to the amplifying means.

6. A bass reproduction speaker apparatus according to claim 1, wherein said bass reproduction speaker apparatus forms a band-pass type speaker.

7. A bass reproduction speaker apparatus according to claim 1, wherein the feedback means comprises a low-pass filter.

8. A bass reproduction speaker apparatus according to claim 7, wherein the feedback means further comprises an integrating circuit.

9. A bass reproduction speaker apparatus according to claim 7, wherein the feedback means further comprises a differentiating circuit.

10. A bass reproduction speaker apparatus according to claim 2, wherein the sensor generates a signal which is in proportion to an acceleration of the vibration of the moving system of the speaker unit.

11. A bass reproduction speaker apparatus according to claim 2, wherein the sensor generates a signal which is in proportion to a velocity of the vibration of the moving system of the speaker unit.

12. A bass reproduction speaker apparatus according to claim 2, wherein the sensor generates a signal which is in proportion to a displacement of the moving system of the speaker unit.

13. A bass reproduction speaker apparatus according to claim 5, wherein the second detection means is a microphone.

14. A bass reproduction speaker apparatus according to claim 5, wherein the second feedback means conducts a motional feedback.

15. A bass reproduction speaker apparatus according to claim 1, wherein said output signal comprises a voltage signal which is proportional to movement of said moving system.

16. A bass reproduction speaker apparatus, comprising:

a cabinet with an opening, having a division member inside thereof, the division member dividing the cabinet into a front cavity and a back cavity;

a first speaker unit disposed at the division member, the first speaker unit being placed inside the back cavity;

a second speaker unit disposed in the opening, the second speaker unit being placed within the front cavity, the second speaker unit acting passively in response to the first speaker unit;

an amplifying means for driving the first speaker unit;

a first detection means for detecting a vibration of the first speaker unit;

a first feedback means for feeding back an output signal from the first detection means to the amplifying means;

a second detection means for detecting a vibration of the second speaker unit; and

a second feedback means for feeding back an output signal from the second detection means to the amplifying means,

wherein the first feedback means conducts both a velocity-type motion feedback and an acceleration-type motion feedback simultaneously over the same frequency band such that the acceleration-type motion feedback substantially aligns a height of peaks in an output sound pressure level versus frequency response of the speaker apparatus at two resonance frequencies in a low frequency range with each other, and the velocity-type motion feedback suppresses the peaks to obtain a substantially flat output sound pressure level over a wide range of low frequencies.

17. A bass reproduction speaker apparatus according to claim 16, wherein the second detection means is a moving coil sensor of the second speaker unit.

18. A bass reproduction speaker apparatus according to claim 16, wherein a resonance occurs in both the front cavity and the back cavity for reproducing bass sound signals.

19. A bass reproduction speaker apparatus, comprising:

a cabinet with an opening, having a division member inside thereof, the division member forming a closed space inside the cabinet;

a speaker unit disposed at the division member, the back face of the speaker unit being disposed in the closed space;

a port provided in the opening;

an amplifying means for driving the speaker unit;

a detection means for detecting a vibration of a moving system of the speaker unit; and

a feedback means for feeding back an output signal from the detection means to the amplifying means, the feedback means conducting both a velocity-type motion feedback and an acceleration-type motion feedback simultaneously over the same frequency band such that the acceleration-type motion feedback substantially aligns a height of peaks in an output sound pressure level versus frequency response of the speaker apparatus at two resonance frequencies in a low frequency range with each other, and the velocity-type motion feedback suppresses the peaks to obtain a substantially flat output sound pressure level over a wide range of low frequencies.

20. A bass reproduction speaker apparatus according to claim 19, further comprising a second detection means for detecting a vibration of the air in the port;

and a second feedback means for feeding back an output signal from the second detection means to the amplifying means.

21. A bass reproduction speaker apparatus, comprising:

a speaker unit driven by an amplifier, the amplifier for driving the speaker unit as a function of a feedback signal;

a detection means for detecting movement of the speaker unit as a result of the amplifier, and for producing the feedback signal as a function of the movement, wherein the detection means comprises a detector selected from a group consisting of a microphone, a piezoelectric sensor, a moving coil sensor, a light quantity detection sensor, a laser Doppler sensor, and an electrostatic sensor; and

a feedback means for feeding back the feedback signal from the detection means to the amplifying means, the feedback means conducting both a velocity-type motion feedback and an acceleration-type motion feedback simultaneously over the same frequency band such that the acceleration-type motion feedback substantially aligns a height of peaks in an output sound pressure level versus frequency response of the speaker apparatus at two resonance frequencies in a low frequency range with each other, and the velocity-type motion feedback suppresses the peaks to obtain a substantially flat output sound pressure level over a wide range of low frequencies.

22. A bass reproduction speaker apparatus, comprising:

a cabinet which has openings on respective opposing sides thereof and has division members inside thereof;

passive radiators provided in the respective openings;

a speaker unit disposed between the division members, the main axis of radiation of the speaker unit being perpendicular to the axes of radiation of the passive radiators;

an amplifying means for driving the speaker unit;

a detection means for detecting a vibration of a moving system of the speaker unit; and

a feedback means for feeding back an output signal from the detection means to the amplifying means.

23. A bass reproduction speaker apparatus according to claim 22, wherein the passive radiators provided in the respective openings have the same effective moving mass and effective diaphragm area.