A synthesizer (also synth, synthesiser) is an electronic musical instrument that works by creating electric signals that are converted through amplifiers and loudspeakers. Synths can create electronic timbres, but they can also imitate, with different levels of accurracy, the sounds of other instruments (such as pianos, organs, string/wind instruments, etc.) or natural sounds. Synths are often played through a keyboard, but they can be controlled by many other imput devices, including but not limited to: sequencers, electronic drum pads, wind controllers, guitar controllers, fingerboards, etc. These usually rely on the MIDI protocol.