A sound effect-creating device frequency-modulates a monaural original sound signal obtained from stereophonic sound signals, delays the resulting modulated signal by delay amounts different from each other, selects and adds up a combination of a plurality of delayed modulated signals to form signals to be added to the stereophonic sound signals, and outputs the resulting stereophonic sound signals.
Early reflection sounds and subsequent reverberation sounds are processed in different modes by separate processing devices in order to obtain reverberation effects close to those of natural sound as well as to freely produce reverberation effects that do not exist in natural sound. When the early reflection sound overlaps the subsequent reverberation sound in time, the early reflection sound and the subsequent reverberation sound are produced without noise. There is no need to omit either one of them. Besides, complex envelope control is executed for the early reflection sound, and the envelope levels are weighted and fluctuated. Therefore, it is possible to establish a highly sophisticated sound field.
A method and apparatus for performing audio post processing using mode information that indicates the degree of similarity between a right channel signal and a left channel signal in MPEG-1 layer 3 audio data, are provided. If the difference between the two channel signals is small, a first mode is used in which the high frequency component of only one channel is recovered and the recovered high frequency component is used to recover the high frequency component of the other channel. If the difference between the two channel signals is large, a second mode is selected in which the high frequency component in only one of every two frames is recovered alternately in the left channel and the right channel and the high frequency component of each of the skipped frames is interpolated based on the high frequency components of the previous frame and the next frame.
A rear speaker and a front speaker are provided in a room. A microphone is disposed at a listening position between the front and rear speakers for picking up a first sound from the front speakers and a second sound from the rear speaker. Time lags of the first sound and the second sound is obtained from the outputs of the microphone, and the time difference between the time lags is obtained. An antiphase audio signal opposite to a reflected composite signal included in the first sound picked up by the microphone is provided by the sound field correcting circuit. The antiphase audio signal with the same amplitude is delayed based on the time difference and emitted from the rear speaker so as to cancel the reflected composite signal.
