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Speaker apparatus

  • US 4,592,088 A
  • Filed: 06/12/1984
  • Issued: 05/27/1986
  • Est. Priority Date: 10/14/1982
  • Status: Expired due to Fees
First Claim
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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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