Speakers are electroacoustic transducers which convert an electrical audio signal into sound. The most common type of speaker are dynamic loudspeakers, but other common speakers include full-range drivers, subwoofers, woofers, mid-range drivers, tweeters, coaxial drivers and horn loudspeakers. Speakers are commonly used in the home or in the form of mini discos for events. However, they also serve an important function in a much wider context, when used at concerts, festivals or public events to amplify and output audio to large audiences. Speakers are also commonly used in phones, laptops and PCS, in fact – any electronic device that relies on the function of audio sound transmission.