The chorus effect creates the illusion that there are multiple versions of a sound occurring simultaneously. The classical use of chorus is to apply it to a solo vocal recording, with the result sounding as if there are multiple singers. The affect is achieved by mixing the original signal with the output of a slowly changing delay line. The delay time is modulated by a sinusoidal low frequency oscillator, which causes the delay time to periodically increase and then decrease. When the delay time is decreasing the pitch of the output is higher than the pitch of the input, and when the delay time is increasing the output is lower in pitch. The result is that the output of the delay line always sounds slightly different than the original signal, and the listener interprets this as being due to a different sound source.
For the two, four, and six-channel modes, each channel has its own delay line. The output of the delay line is mixed with the original signal and also fed back to the delay line input. There is a low-frequency sinusoidal oscillator, which is used to change the delay length of each delay line. Since the desired delay time may not be an integer number of samples the delay line output is linearly interpolated between adjacent samples.