First, the rated impedance and the gallbladder modified impedance characteristic loudspeaker system's rated impedance by the speaker unit rated impedance which uses decided generally. loudspeaker system's impedance characteristic relation speaker unit's impedance characteristic wants complex many. This is because the loudspeaker system uses the speaker unit are many and varied, and has added on the dividing network influence. The box body's influence, causes the entire loudspeaker system's impedance characteristic along with the structure pattern, to use the unit and the frequency divider has the big change. Second, the distortion loudspeaker system's distorted characteristic, is more complex than the cabinet loudspeaker, it is by is composed loudspeaker system's each part of distorted synthesis to obtain, these parts include: Composition system's each speaker's distortion; The box in vivo standing wave and the stave sheet vibration cause the distortion, the dividing network produces distortion and so on. Third, the nominal frequency scope, the effective frequency range loudspeaker system replay's nominal frequency scope stipulated by the product standard, the loudspeaker system achieves actually the frequency range is called the effective frequency range. In the ideal situation, the loudspeaker system should achieve in person ear audible frequency scope 16~20000Hz, practical, domestic and foreign generally frequency range design in 40~20000Hz. Fourth, the characteristic sensitivity level, the maximum output acoustic pressure level loudspeaker system's characteristic sensitivity level and the speaker are under equally the 1W initial conditions, according to GB code GB9396-88 (test criteria), GB9399YI88 (technical standard) stipulated is apart from a sound pressure decibel number which speaker 1M place obtains, may calculate loudspeaker system's big output acoustic pressure level by the characteristic sensitivity level. Fifth, the rating biggest noise power, the fixed biggest noise power loudspeaker system's rating biggest noise power refers to for a long time in the nominal frequency scope feeds the simulation program signal which stipulated for the loudspeaker system, but does not produce the heat generation and machinery's damage biggest noise voltage. Sixth, the pure tone loudspeaker system examines listens when should the non-mechanical sound, bump puts circles as tone marks at the corners of Chinese characters, trash sound, the double sound and so on.