Relevant parameters of headphones
Notice the difference between resistance and resistance. In the world of direct current (DC), the effect of object on current obstruction is called resistance, but in the field of alternating current (AC), besides resistance, capacitance and inductance can also obstruct current flow. This effect is called resistance, which we call impedance everyday. It is the sum of resistance and reactance on the vector.
The sound pressure level (the unit of sound pressure is decibel, the louder the sound pressure is, the larger the volume) can be emitted when the power is input to the earphone at 1 mW. Therefore, the higher the general sensitivity and the smaller the impedance are, the easier the earphone is to produce sound and drive.
The sensitivity value corresponding to the frequency is the frequency response, and the drawing of the image is the frequency response curve. The range of human hearing is about 20Hz-20000Hz. The mature earphone technology has reached this requirement.