Speaker performance index

Speaker is a key part of speaker system (commonly known as the speaker), speaker sound reproduction quality is mainly composed of the performance index of the speaker decided and determine the set of playback indicator. The performance index of the speaker mainly has the rated power, the rated impedance, the frequency characteristic, the harmonic distortion, the sensitivity, the direction and so on.

　　The performance of the speaker mainly through the following indicators to measure:

　　1、Rated power（W）d

　　Speaker distortion has a lot of kinds, common have harmonic distortion (many by speaker magnetic field inhomogeneity and vibration system distortion caused by, often happen at low frequencies), intermodulation distortion (distortion due to two different frequency signals at the same time with a loudspeaker, mutual modulation caused by the degradation of sound quality) and transient (due to inertia vibration system can not follow the change of signal change, causing the signal distortion). When the harmonic distortion is reproduced, the harmonic components of the original signal are added. The harmonic distortion of the loudspeaker is derived from the nonlinear distortion of the magnetic field, the characteristics of the vibration film, the displacement of the voice coil. At present, the harmonic distortion of the speaker is not more than 5[%].

　2、Sensitivity（dB/W）

　　The sensitivity of the speaker is usually measured by the sound pressure of the loudspeaker, when the input power is 1W of the noise voltage. The sensitivity is a measure of the speaker of the audio signal in detail whether the reproduction index slip over nothing whether big or small. The higher the sensitivity, the speaker's response to all the details of the audio signal. The sensitivity of the Hi-Fi speaker should be greater than 86dB/W.

　　3、Directivity

　　In different directions, the sound pressure frequency characteristics are different, which is called the directivity of the loudspeaker. It is related to the size of the speaker, the diameter of the pointed at the point of a large diameter, the diameter of an hour to point. Directivity is also related to frequency, generally speaking, there is no obvious directional signal to 250Hz. High frequency signal of the following 1.5kHz has obvious directivity.