Computer speakers, or multimedia are speakers sold for use with computers, although usually capable of other audio uses, e.g. an MP3 player. Most such have internal amplifier and consequently require a power source, which may be by mains supply often via AC adapter, batteries, USB port. The signal input connector is 3.5 mm jack plug (usually color-coded lime green per the PC 99 standard); RCA connectors sometimes used, port both (requiring additional circuitry, only suitable computer). Battery-powered wireless Bluetooth no connections at all. computers low quality built in; when external connected they disable built-in speakers. Altec Lansing claims to created computer speaker market in 1990.[1] range widely price. packaged systems small, plastic, mediocre sound quality. Some equalization features as bass treble controls. can using Aux compatible adaptor.[2] More sophisticated subwoofer unit, enhance output. larger enclosure contains amplifiers left right displays rather basic built-in. Laptop integrated small restricted conserve space.