Electrical recording made it possible to record one part to disc and then play that back while playing another part, recording both parts to a second disc. This is called "over-dubbing". The first commercially issued records using over-dubbing were released by the Victor Talking Machine Company in the late 1920s. However overdubbing was of limited use until the introduction of analog audio tape. Use of tape overdubbing was pioneered by Les Paul and is called 'sound on sound' recording. In this way performances could be built up over time.