A percussion idiophone developed in the 1920's, used much in jazz music. It consists of metal bars arranged in the manner of a piano keyboard, and it is sounded by means of soft mallets. It looks similar to a marimba, only with metal bars. A series of resonator tubes are hung under the metal bars. Each of the resonator tubes has a disc in them that rotates to open and close the tube, thus altering the pattern of vibrations for the pitches that are sounded. This process provides a soothing pulsation similar to a vibrato. This vibrato effect can be controlled by the performer from no vibrato to a slow vibrato to a very fast vibrato. This wide range of vibrato possibilities provides a broad palette of sounds for the performer and are controlled by the speed of the spinning discs with a variable speed electric motor. Usually the vibraphone has a three octave range of f to f3. Some vibraphones have an extended range from c to f3. It is also known as the vibraharp.