Abstract: Signal components of one stereo channel are transposed into the other channel dynamically as a function of stereo signal characteristics to cancel noise components. Thus, at low amplitudes monophonic output is produced at reduced noise levels and at higher amplitudes, the system reverts to stereophonic operation with a smooth transition from monophonic to stereo mode of operation. This system, for example, eliminates most vertical stylus motion noise caused by record groove surface flaws and by vibrations from the playback mechanism.