IP Library Granted Patent US 8,139,798
Granted Patent B2
US 8,139,798 · App. 11/668,108 · Granted Mar 20, 2012

Sound reproducing apparatus

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Quick Facts
Patent No.
US 8,139,798
App. No.
11/668,108
Granted
Mar 20, 2012
Kind
B2
Abstract

A sound reproducing apparatus is provided with a circuit comprising a first secondary phase shifter in a front stage of at least one of channels among a first power amplifier, a second power amplifier and a third power amplifier, and a second secondary phase shifter and an adder in at least one of remaining channels for providing an output by adding output signals of a music signal source and the second secondary phase shifter. The apparatus of this structure eliminates phase interferences between a center speaker and right and left speakers by controlling sound waves generated by the center speaker, thereby achieving excellent reproduction of music.

Claims (19)

1. A sound reproducing apparatus comprising:

a music signal source;

at least three channels of power amplifiers for amplifying an output signal of the music signal source; and

at least three speakers for reproducing music by outputs of the power amplifiers,

wherein at least one channel of the power amplifiers includes at least one secondary phase shifter prior to the respective power amplifier, and

at least one remaining channel has at least one other secondary phase shifter and an adder prior to the respective power amplifier, the adder providing an output by adding the output signal of the music signal source and an output signal of the at least one other secondary phase shifter.

2. A sound reproducing apparatus comprising:

a music signal source;

at least three channels of power amplifiers for amplifying an output signal of the music signal source; and

at least three speakers for reproducing music from the music signal source by outputs of the power amplifiers,

wherein at least two channels of the power amplifiers each comprises at least one secondary phase shifter prior to the respective power amplifier, and

at least one remaining channel has at least one other secondary phase shifter and an adder prior to the respective power amplifier, the adder providing an output by adding the output signal of the music signal source and an output signal of the at least one other secondary phase shifter.

3. The sound reproducing apparatus of claim 1 further comprising a gain control stage prior to the at least one other secondary phase shifter and the adder of the at least one remaining channel.

4. The sound reproducing apparatus of claim 2 further comprising a gain control stage prior to the at least one other secondary phase shifter and the adder of at least one remaining channel.

5. The sound reproducing apparatus of claim 1 , wherein

the at least one secondary phase shifter prior to the respective power amplifier of the at least one channel and the at least one other secondary phase shifter prior to the adder of the at least one remaining channel have a common center frequency of phase reversion.

6. The sound reproducing apparatus of claim 2 , wherein

each of the at least one secondary phase shifter of the at least two channels of the respective power amplifiers has a different center frequency of phase reversion, and

the at least one remaining channel includes at least two other secondary phase shifters, each of the at least two other secondary phase shifters has a different center frequency of phase reversion.

Assignments (2)
CHANGE OF NAME Recorded Mar 6, 2009
From: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
To: PANASONIC CORPORATION
Reel/Frame 022363/0306 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 7, 2007
From: KOTEGAWA, KAZUHISA; KONNO, FUMIYASU; NAGASAWA, SHINNOSUKE
To: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Reel/Frame 019396/0426 →