Philips Electronics North America Corporation

Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Philips Electronics N.a. Corporation

Wayne Milton Schott

A loudspeaker includes an acoustical enclosure having an internal wall dividing the enclosure into first and second subchambers, an electro-acoustical transducer having a vibratable speaker cone mounted in an opening in the internal wall of the acoustical enclosure, an internal vent in the internal wall of the acoustical enclosure for pneumatically coupling the first and second subchambers, a first external vent in a wall of the first subchamber for pneumatically coupling the first subchamber to an exterior environment outside of the acoustical enclosure, and a second external vent in a wall of the second subchamber for pneumatically coupling the second subchamber to the exterior environment, a ratio of the acoustic masses of the internal vent to the the second external vent being approximately 3/1 to 7/1, and a ratio of the acoustic masses of the first external vent to the second external vent being approximately 15/1 to 30/1.

Loudspeaker having a dual chamber acoustical enclosure with two external vents and one internal vent

A circuit for providing a variable amount of bass control on an input signal dependent on a signal level of the input signal includes a high-pass filter, a variable impedance shunt connected to the output of the high-pass filter, and a signal level detector for controlling the variable impedance shunt. Depending on the signal level, the variable impedance shunt varies the Q value of the high-pass filter so that at low signal levels, the Q value is at its maximum while at high signal values, the Q value is lowered.

Dynamic bass control circuit with variable cut-off frequency

A loudspeaker enclosure includes a rectangular cabinet having an acoustical port mounted in one of the vertical walls. A loudspeaker is installed in a bottom wall of the cabinet facing away from an interior volume of the cabinet. A highly resistive acoustic foam is positioned in front of the loudspeaker to restrict the direct radiation of the loudspeaker, so that the usable acoustic radiation emanates from the acoustical port.

Vented loudspeaker enclosure with limited driver radiation

The present invention is directed to a circuit for performing volume expansion on an audio signal. The circuit includes an amplifier that has an input side and an output side. Further, the amplifier amplifies the audio signal at a first amplification to produce an amplified signal at the output side of the amplifier. The circuit also includes a shunting element coupled across the input side and output side of the amplifier. The shunting element includes a variable impedance device for changing the first amplification of the amplifier to a second amplification if the amplified signal reaches a predetermined threshold.

High volume expander circuit

In portable stereo radio receivers and television receivers, the loudspeakers therein may be separated only by a limited amount. This severely restricts the stereo image created by the loudspeakers. A circuit arrangement for creating an expanded stereo image may be incorporated in such receivers. This circuit arrangement includes, for each stereo channel, a first and a second all-pass 0.degree.-180.degree. phase shifter, wherein the first phase shifter shifts the input signal by 90.degree. at a frequency of 10 KHz, while the second phase shifter shifts the input signal by 90.degree. at a frequency of 100 Hz. The output from the first phase shifter in the left channel is combined with the output from the second phase shifter in the right channel to form the left channel output signal. Similarly, the output from the first phase shifter in the right channel is combined with the output from the second phase shifter in the left channel to form the right channel output signal.

Method and circuit for creating phantom sources using phase shifting

In portable stereo radio receivers and television receivers, the loudspeakers therein may be separated only by a limited amount. This severely restricts the stereo image created by the loudspeakers. A circuit arrangement for creating an expanded stereo image may be incorporated in such receivers. This circuit arrangement first forms a combined monaural signal and a differential signal from the two stereo signals. The differential signal is then subjected to a phase shift. The phase-shifted differential signal is then matrixed with the combined monaural signal to form output stereo signals. When reproduced through stereo loudspeakers, the stereo image appears to be greatly expanded, beyond the limited placement of the loudspeakers.

Method and circuit for creating an expanded stereo image using phase

By using special frequency response manipulation in the difference channel of a stereo signal, the stereo image will appear to extend beyond the actual placement of the loudspeakers. This is accomplished by shaping the difference channel response to simulate the response one would be subjected to if the sources were physically moved to the virtual positions. The circuit includes a summing and high frequency equalization circuit to which the left and right stereo signals are applied, and a difference forming and human ear equalization circuit also to which the left and right stereo signals are applied. The outputs from these circuits are cross-coupled to form left and right channel outputs.

Circuit for improving the stereo image separation of a stereo signal

An equalizing circuit, for compensating frequency response perturbations in a loudspeaker caused by a recessed mounting of the loudspeaker, includes an input for receiving an audio signal, a peaking network coupled to the input for augmenting the audio signal in a first frequency range, a dipping network also coupled to the input for attenuating the audio signal in a second frequency range, and a combiner for combining an output of the peaking network to an output of the dipping network, an output of the combiner carrying a compensated audio signal for application to the loudspeaker.

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Seymour, TN, United States of America

Wayne Milton Schott