An electric musical instrument is one in which the use of electric devices determines or affects the sound produced by an instrument. Electric musical instruments are an example of electric music technology. It is also known as an amplified musical instrument due to the common utilization of an electronic instrument amplifier to project the intended sound as determined by electric signals from the instrument. Two common types of instrument amplifiers are the guitar amplifier and the bass amplifier. This is not the same as an electronic musical instrument, like a synthesizer, which uses entirely electronic means to both create and control sound.