... sound quality.The product's function and usage as follows.1.Button section:Volume +, Volume -, MODE buttonVolume +:Press this ... ,speaker,chamber and amplifier,the precise coordination and the overall match , to be the best sound quality.8.Technical parameters ... , Speaker Technical parameters:Output power: 2W * 2;Distortion: 0.1%;Efficiency: 90%;Frequency response: 100HZ-20KHZ;Full-range speakers: 2W ...