A level sensitive audio noise reduction scheme that involves compression, on the encode side, and expansion, on the decode side. It was originally developed for CBS for noise reduction on LP records and is a trademark of CBS, Inc. The noise reduction obtained by CX was to be better than Dolby B3 for tape, but remain unnoticeable in playback if decoding didn’t take place. A modified CX system was applied to the analogue audio tracks for the laserdisc to compensate for interference between the audio and video carriers. The original CX system for LP records was never implemented.