| 摘要 |
PURPOSE: To make a spread sense of a surrounding sound and a reverberation sound compatible with a moving sense of the sounds by applying pseudo stereophonic processing to a Dolby surround signal having no surround information at frequencies below a specific frequency and applying monaural processing to the signal at frequencies over the specific frequency. CONSTITUTION: An input monaural signal is separated into a high frequency component, a medium frequency component and a low frequency component by an HPF 1, a BPF 2 and an LPF 3. A pseudo stereo processing circuit 4 receives the medium frequency component and converts the component into two signals with small correlation and provides the output of them. An adder circuit 5 adds the high frequency component, one output of the pseudo stereo processing circuit 4 and the low frequency component to obtain an output 1. An adder circuit 6 adds the high frequency component, the other output of the pseudo stereo processing circuit 4 and the low frequency component inverted by an inverting circuit 7 to obtain an output 2. A moving sound including many high frequency components remains a monaural signal, then a difference from a sound image is small even in the case of movement forward/backward. The surrounding sound and reverberation sound including many low frequency components have an extended stereophonic effect by the phase difference between the outputs 1 and 2 to intensity a spread sense. |
