Electronic music is music that employs electronic musical instruments, digital instruments and circuitry-based music technology. In general, a distinction can be made between sound produced using electromechanical means (electroacoustic music), and that produced using electronics only. Electromechanical instruments include mechanical elements, such as strings, hammers, and so on, and electric elements, such as magnetic pickups, power amplifiers and loudspeakers. Examples of electromechanical sound producing devices include the telharmonium, Hammond organ, and the electric guitar, which are typically made loud enough for performers and audiences to hear with an instrument amplifier and speaker cabinet. Pure electronic instruments do not have vibrating strings, hammers, or other sound-producing mechanisms. Devices such as the theremin, synthesizer, and computer can produce electronic sounds.