Main performance index of speakers

　　The main performance indicators are: sensitivity, frequency response, rated power, rated impedance, directivity, distortion and other parameters.
　　1、Rated power
　　The speaker's power is divided into the nominal power and the maximum power. Rated power, non distortion power. It refers to the maximum input power of the speakers at the nominal distortion range, and the power that is marked in the speaker's trademark and the technical specification is the value of the power. The maximum power is the peak power of the speaker at a certain moment. In order to ensure the reliability of the maximum power is raised, speaker is 2~3 times the nominal power.
　　2、Nominal impedance
　　The speaker's impedance is generally related to the frequency. The nominal impedance is the impedance of the measured impedance when the audio is 400Hz. It is generally 1.2~1.5 times the DC resistance of the voice coil. Common impedance of moving coil loudspeaker is 4 ohm, 8 ohm, 16 ohm, 32 ohm.
　　3、Frequency response
　　The sound pressure produced by the sound pressure will be changed when a speaker is added to the same voltage and different frequency of the audio signal. The sound pressure produced by the general audio is relatively large, while the sound pressure is smaller when the low and high audio. When the sound pressure drops to a certain value of the audio frequency range, the frequency response of the loudspeaker is called.
　　The ideal speaker frequency should be 20~20KHz, so that all the audio can be reproduced evenly, but this is not done. Each speaker only has a good portion of the audio playback.
　　4、Distortion
　　The speaker can not reproduce the original sound phenomenon called distortion. There are two types of distortion: frequency distortion and nonlinear distortion. Frequency distortion is due for some frequency signal playback is strong, and of other frequency signal reproducing weak caused distortion destroy the proportion of the original high bass loudness, changed the original instrument sound. The nonlinear distortion is caused by the vibration of the vibration of the loudspeaker system, and the wave of the signal is not completely consistent.
　　5、Directional characteristics
　　Used to characterize the sound pressure distribution characteristics of the speakers in the space, the higher the frequency, the higher the directivity, the larger the paper basin.