The system is configured with a head-mounted microphone and a wireless lavalier wireless microphone designed to have a variety of wired microphone input audio signal input unit and a power supply unit with a rechargeable battery box, according to the design of the need to use high bass circuit, the tone output can be adjusted to control the design of output power 20W audio mixing function space ideal distance of 40 meters using parameters: Audio output power: 20W (MAX) Frequency range: 100Hz-15KHz SNR: 60dB Power supply voltage: AC220V / 50Hz DC12-15V receiving mode: VHF / FM Output Impedance: 600Ω receiving distance: 20-40m (under ideal conditions) Dynamic Range: 80dB Working temperature: -10 C-45 C Battery: 9V laminated battery Battery life: 10-30 hours ?