The Leslie speaker is a combined amplifier and loudspeaker that modifies the sound of an instrument as well as amplifying it, by rotating sound waves. The speaker is named after its inventor, Donald Leslie. Leslie began working in the late 1930s to get a speaker for a Hammond organ that had a closer emulation of a pipe or theater organ, and discovered that rotating sound gave the best effect. Hammond was not interested in marketing or selling the speakers, so Leslie sold them himself as an add-on, targeting other organs as well as Hammond. The first speaker was made in 1941. The sound of the organ being played through his speakers received national radio exposure across the US, and it became a commercial and critical success as an essential part of any jazz organist. He eventually sold his business to CBS in 1965, who in turn sold it to Hammond in 1980. Today, the Hammond and Leslie brands are owned by Suzuki Musical Instrument Corporation.