Method of harmonizing the impedances of an audio amplifier and loudspeaker interconnected therewith

• US 4,387,270 A
• Filed: 11/28/1980
• Issued: 06/07/1983
• Est. Priority Date: 03/24/1980
• Status: Expired due to Term

• Current Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
• Original Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
• Inventors: Sakano, Hideki, Todokoro, Shigeru
• Primary Examiner(s): Rubinson, G. Z.
• Assistant Examiner(s): Lev, R.
• Application Number:
  US06/211,187
• Time in Patent Office: 921 Days
• Field of Search: 179/1 A, 179/1 F, 179/175.1 R, 179/175.1 A, 330/2, 330/291, 330/292, 330/75
• US Class Current: 381/96
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 3/181 Low-frequency amplifiers, e.g. audio preamplifiers
• CPC Class Codes: H04B 3/40 Artificial lines; Networks simulating a line of certain length
• CPC Class Codes: H04R 3/002 Damping circuit arrangements for transducers, e.g. motional feedback circuits

Abstract

A method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith, the audio amplifier including a line amplifier and a positive feedback circuit for compensating for the counter electromotive force of the loudspeaker. A voice coil of the loudspeaker is mechanically driven for generating an electric signal at input terminals of the loudspeaker. Then, the amplification degree of the line amplifier or the positive feedback circuit is adjusted to reduce the signal voltage between the input terminals of the loudespeaker to a minimum, during the circulation of the generated signal through the positive feedback circuit and the line amplifier.

Claims

1. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith, the audio amplifier including a line amplifier and a positive feedback circuit for compensating for the counter electromotive force of the loudspeaker, the method comprising:

mechanically driving a voice coil of the loudspeaker to generate an electrical signal; and

minimizing the voltage between the input terminals of the loudspeaker by adjusting the amplification degree of the line amplifier or the positive feedback circuit during the circulation of the generated signal through the positive feedback circuit and the line amplifier.

2. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith according to claim 1 wherein said step of mechanically driving the voice coil of the loudspeaker is accomplished by tapping the diaphragm of the loudspeaker.

3. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith according to claim 1 wherein said step of mechanically driving the voice coil of the loudspeaker is accomplished by a sound acting on the diaphragm of the loudspeaker.

4. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith according to claim 3 wherein the sound is produced by another loudspeaker connected to another audio amplifier.

5. The method of harmonizing the impedances of an audio amplifier and a loudspeaker connected therewith according to claim 4 wherein said latter audio amplifier and said latter loudspeaker constitute a first audio amplifier and a first loudspeaker and wherein said method includes the step of utilizing a second audio amplifier and a second loudspeaker to complete a set of stereo apparatus with said first audio amplifier and first loudspeaker and wherein said second audio amplifier constitutes said another audio amplifier.

6. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith according to the claim 1 wherein said step of minimizing the voltage between the input terminals of the loudspeaker includes connecting a voltage sensitive indicator between the input terminals of the loudspeaker before the step of mechanically driving a voice coil of the loudspeaker.

7. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith according to the claim 6 wherein the indicator is a voltmeter.

8. The method of harmonizing the impedances of an audio amplifier and a loudspeaker interconnected therewith according to claim 6 wherein the indicator is a light emitting diode.