The performance of headset speakers is mainly measured by the following indexes:
1. Rated Power (W)d
There are many kinds of distortions in the headphone speaker. Harmonic distortion, intermodulation distortion, and transient distortion are common. Harmonic distortion refers to the increase of harmonic components that are not present in the original signal during playback. Harmonic distortion of the speaker comes from the non-linear distortion of the magnetic field of the magnet, the characteristics of the diaphragm, and the displacement of the voice coil. At present, the harmonic distortion index of a better speaker is not more than 5%.
2. Headphone Speaker Sensitivity (dB/W)
The sensitivity of a headphone speaker usually refers to the sound pressure measured at 1 m in front of the speaker's axial direction when the noise input voltage is 1 W. Sensitivity is a measure of whether the speaker can reproduce the details of the audio signal in great detail. The higher the sensitivity, the speaker can respond to all details in the audio signal. The sensitivity of a Hi-Fi speaker should be greater than 86 dB/W.
3. Headphone Speaker Directionality
Headphone speakers have different sound pressure frequency characteristics for radiation in different directions. This characteristic is referred to as speaker directivity. It is related to the caliber of the speaker. When the caliber is large, the directionality is pointed and the caliber is small. The directivity is also related to the frequency. In general, there is no obvious directivity for low frequency signals below 250Hz. For the high frequency signal below 1.5kHz, there is obvious directivity.