light tone Mulight. 36Kr News: Recently, Aauto Quicker has launched a tool-based product named Optical Mulight, which is tailored for music lovers. At present, Guangyin has been launched in the Android AppStore and Apple's App Store. According to official data, Guangyin is a mobile APP specially designed for music lovers who play and sing. Its main function is to add lyrics and subtitles with one click, and easily record and publish MVs.