Speaker apparatus
First Claim
1. A speaker apparatus comprising:
- an input terminal for receiving an input signal;
a speaker for radiating a sound wave, said speaker having a sound wave radiation axis;
a power amplifier connected between said input terminal and said speaker for driving said speaker to produce a sound wave;
a feedback amplifier;
a microphone for detecting the sound wave from said speaker and connected to said power amplifier via said feedback amplifier for feeding back to said power amplifier a feedback signal which has a frequency range below an upper limit frequency, said microphone being disposed in a plane which is substantially perpendicular to the direction of said sound wave radiation axis, and wherein said plane substantially contains an acoustic center of said speaker and said microphone is located at a distance from said sound radiation axis which is not greater than 1/4 of the wavelength corresponding to the upper limit frequency of the feedback signal.
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Accused Products
Abstract
A speaker apparatus using the so-called motional feedback (MFB) technique in which the sound wave from a speaker (14) is detected by a microphone (10) and the output of the microphone (10) is fed back to a power amplifier (5) for driving the speaker through a feedback amplifier (11). The microphone (10) is disposed in a plane which is perpendicular to the sound radiation axis of the speaker such plane containing substantially the acoustic center of the speaker (14). The output of the microphone (10) is fed back to the power amplifier (5) within a frequency range lower than a frequency at which the distance between the speaker (14) and the microphone (10) becomes 1/4 wavelength. A speaker apparatus is thus realized where the reproduced sound is not influenced by the microphone, the feedback upper limit frequency is high and the influence of Doppler distortion is small.
163 Citations
11 Claims
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1. A speaker apparatus comprising:
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an input terminal for receiving an input signal; a speaker for radiating a sound wave, said speaker having a sound wave radiation axis; a power amplifier connected between said input terminal and said speaker for driving said speaker to produce a sound wave; a feedback amplifier; a microphone for detecting the sound wave from said speaker and connected to said power amplifier via said feedback amplifier for feeding back to said power amplifier a feedback signal which has a frequency range below an upper limit frequency, said microphone being disposed in a plane which is substantially perpendicular to the direction of said sound wave radiation axis, and wherein said plane substantially contains an acoustic center of said speaker and said microphone is located at a distance from said sound radiation axis which is not greater than 1/4 of the wavelength corresponding to the upper limit frequency of the feedback signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification