The Infrared Wireless Microphone System using this IR-820SP is a PA system designed for use in the school classrooms assuming that their size is about 10 m × 10 m (30 ft × 30 ft). The IR-820SP is a ceiling-mounted powered speaker with the infrared receiver and offers a wide frequency range of high-quality sound output. It features a digital amplifer for the amplification section, and a full-range speaker for the speaker section. Use of the supplied mounting hardware and optional HY-TB1 Tile Bar Bridge permits it to be versatilely mounted to match a wide range of applications and installation locations. This speaker is combined with an infrared wireless microphone and the IR-802T Infrared Wireless Tuner to make up the infrared wireless microphone system. The infrared microphone system eliminates problems with interference or eavesdropping, allowing simultaneous use in adjacent school classrooms.