Abstract: A diffuser which forms a first acoustic passage that sound waves propagate and which radiates the sound waves to an outer diameter direction between a diaphragm and an annular conical surface of a first reflection member, and forms a second acoustic passage the sound waves which pass the opening of the first reflection member propagate and which radiates the sound waves to an outer diameter direction between the annular concave surface of the first reflection member and a conical surface of a second reflection member.

Abstract: A diffuser which forms a first acoustic passage that sound waves propagate and which radiates the sound waves to an outer diameter direction between a diaphragm and an annular conical surface of a first reflection member, and forms a second acoustic passage the sound waves which pass the opening of the first reflection member propagate and which radiates the sound waves to an outer diameter direction between the annular concave surface of the first reflection member and a conical surface of a second reflection member.

Abstract: A signal processing device configured to perform: low pass filter processing to extract a low frequency component of an audio signal, compression processing to compress the audio signal to which the low pass filter processing is performed in a case that the audio signal to which the low pass filter processing is performed is not less than a predetermined signal level, high pass filter processing to extract high frequency component of the audio signal, first volume processing to attenuate the audio signal, and synthesis processing to synthesize the low frequency component of the audio signal to which the compression processing is performed and high frequency component of the audio signal.

Abstract: A first circuit unit of an audio amplifier includes a first emitter follower connected to an pre stage input terminal, a second emitter follower connected to an pre stage input terminal, a main transistor connected to an output path of the first emitter follower and an output path of the second emitter follower, a first resistor and a second resistor, which are series-connected between the output path of the first emitter follower and a DC voltage source, and a zener diode connected to a series-connection point between the first resistor and the second resistor. A second circuit unit has a circuit configuration that is complementary to the first circuit unit. A path leading to a collector of each transistor configuring the first and second emitter followers in one of the circuit units is connected to the series-connection point in the other circuit unit.

Abstract: To resolve volume shortage of middle and high band of speaker reproduction sound. A DSP 4 performs LPF processing to extract low frequency component of an audio signal to which the first volume processing is performed, DRC processing to compress the audio signal to which the LPF processing is performed in case that the audio signal to which the LPF processing is performed is not less than a predetermined signal level, HPF processing to extract high frequency component of the audio signal to which the first volume processing is performed, second volume processing to attenuate the audio signal to which the HPF processing is performed based on the volume value that is received, and synthesis processing to synthesize the audio signal to which the DRC processing is performed and the audio signal to which the second volume processing is performed.

Abstract: A first circuit unit of an audio amplifier includes a first emitter follower connected to an pre stage input terminal, a second emitter follower connected to an pre stage input terminal, a main transistor connected to an output path of the first emitter follower and an output path of the second emitter follower, a first resistor and a second resistor, which are series-connected between the output path of the first emitter follower and a DC voltage source, and a zener diode connected to a series-connection point between the first resistor and the second resistor. A second circuit unit has a circuit configuration that is complementary to the first circuit unit. A path leading to a collector of each transistor configuring the first and second emitter followers in one of the circuit units is connected to the series-connection point in the other circuit unit.

Abstract: To resolve volume shortage of middle and high band of speaker reproduction sound. A DSP 4 performs LPF processing to extract low frequency component of an audio signal to which the first volume processing is performed, DRC processing to compress the audio signal to which the LPF processing is performed in case that the audio signal to which the LPF processing is performed is not less than a predetermined signal level, HPF processing to extract high frequency component of the audio signal to which the first volume processing is performed, second volume processing to attenuate the audio signal to which the HPF processing is performed based on the volume value that is received, and synthesis processing to synthesize the audio signal to which the DRC processing is performed and the audio signal to which the second volume processing is performed.

Abstract: To realize active control ground that sets inverted output of an amplification circuit to ground with simple configuration. A DAP 1 comprises a positive side DAC 7 that D/A-converts digital audio data into analog audio data, a positive side amplification circuit 9 that amplifies the analog audio data that the DAC 7 D/A-converts, a negative side DAC 8 that D/A-converts the digital audio data into the analog audio data, and a negative side amplification circuit 10 that amplifies the analog audio data that the DAC 8 D/A-converts, and a CPU 2. The CPU 2 mutes the DAC 8 in case of an ACG mode that sets output of the amplification circuit 10 to ground.

Abstract: To reduce signal output and wiring to a D/A converter (DAC). A DAP 1 comprises a DAC 7 that D/A-converts LR 2 channels digital audio data into LR 2 channels analog audio data, an amplification circuit 9 that amplifies the LR 2 channels analog audio data that the DAC 7 D/A-converts, a DAC 8 that D/A-converts the LR 2 channels digital audio data into the LR 2 channels analog audio data, and an amplification circuit 10 that amplifies inverted LR 2 channels analog audio data that the LR 2 channels analog audio data that the DAC 8 D/A-converts is inverted.

Abstract: To realize active control ground that sets inverted output of an amplification circuit to ground with simple configuration. A DAP 1 comprises a positive side DAC 7 that D/A-converts digital audio data into analog audio data, a positive side amplification circuit 9 that amplifies the analog audio data that the DAC 7 D/A-converts, a negative side DAC 8 that D/A-converts the digital audio data into the analog audio data, and a negative side amplification circuit 10 that amplifies the analog audio data that the DAC 8 D/A-converts, and a CPU 2. The CPU 2 mutes the DAC 8 in case of an ACG mode that sets output of the amplification circuit 10 to ground.

Abstract: To reduce signal output and wiring to a D/A converter (DAC). A DAP 1 comprises a DAC 7 that D/A-converts LR 2 channels digital audio data into LR 2 channels analog audio data, an amplification circuit 9 that amplifies the LR 2 channels analog audio data that the DAC 7 D/A-converts, a DAC 8 that D/A-converts the LR 2 channels digital audio data into the LR 2 channels analog audio data, and an amplification circuit 10 that amplifies inverted LR 2 channels analog audio data that the LR 2 channels analog audio data that the DAC 8 D/A-converts is inverted.

Abstract: An amplifying circuit comprises: a first transistor, a second transistor, a third transistor and a fourth transistor provided to an input stage; and a first bias circuit. The input signal is input into a control terminal of the first transistor and a control terminal of the second transistor, a first terminal of the first transistor is connected to a first terminal of the third transistor, a first terminal of the second transistor is connected to a first terminal of the fourth transistor, a second terminal of the first transistor is connected to a first potential, a second terminal of the second transistor is connected to a second potential that is equal to or different from the first potential, a second terminal of the third transistor is connected to a third potential, a second terminal of the fourth transistor is connected to a fourth potential, the first bias circuit is connected between a control terminal of the third transistor and a control terminal of the fourth transistor.

Abstract: The first emitter follower circuit and the second emitter follower circuit can increase an input impedance on the side of the inverting input terminal in the amplifying circuit. As a result, when a feedback circuit is connected between the inverting input terminal and the output terminal of the amplifying circuit, a fluctuation in a gain of the amplifying circuit according to a configuration of the feedback circuit can be suppressed.

Abstract: The first emitter follower circuit and the second emitter follower circuit can increase an input impedance on the side of the inverting input terminal in the amplifying circuit. As a result, when a feedback circuit is connected between the inverting input terminal and the output terminal of the amplifying circuit, a fluctuation in a gain of the amplifying circuit according to a configuration of the feedback circuit can be suppressed.

Abstract: An amplifying circuit comprises: a first transistor, a second transistor, a third transistor and a fourth transistor provided to an input stage; and a first bias circuit. The input signal is input into a control terminal of the first transistor and a control terminal of the second transistor, a first terminal of the first transistor is connected to a first terminal of the third transistor, a first terminal of the second transistor is connected to a first terminal of the fourth transistor, a second terminal of the first transistor is connected to a first potential, a second terminal of the second transistor is connected to a second potential that is equal to or different from the first potential, a second terminal of the third transistor is connected to a third potential, a second terminal of the fourth transistor is connected to a fourth potential, the first bias circuit is connected between a control terminal of the third transistor and a control terminal of the fourth transistor.

Abstract: The present invention provides a vibration-damping structure for an audio apparatus, accommodating a main transformer, which becomes a vibration source when driven, the vibration-damping structure including: a main chassis to which a signal processing board for processing an audio signal is attached, the first chassis defining a portion of an outer shape of an assembly of the vibration-damping structure; a sub-chassis fastened to an inner surface of the main chassis so as to be partially in contact with the inner surface of the main chassis via a plurality of fastening members; and a component accommodating chassis fastened to an inner surface of the sub-chassis so as to be partially in contact with the inner surface of the sub-chassis via other fastening members, wherein the main transformer is fixed to the component accommodating chassis.

Abstract: The present invention provides a vibration-damping structure for an audio apparatus, accommodating a main transformer, which becomes a vibration source when driven, the vibration-damping structure including: a main chassis to which a signal processing board for processing an audio signal is attached, the first chassis defining a portion of an outer shape of an assembly of the vibration-damping structure; a sub-chassis fastened to an inner surface of the main chassis so as to be partially in contact with the inner surface of the main chassis via a plurality of fastening members; and a component accommodating chassis fastened to an inner surface of the sub-chassis so as to be partially in contact with the inner surface of the sub-chassis via other fastening members, wherein the main transformer is fixed to the component accommodating chassis.