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: 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 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.