Itis the sound pressure level produced by the earphone in the artificial ear(dummy head) when the electric power is applied to the earphone at 1 mW. Thepower of 1 mW is calculated based on the standard impedance of the earphone ata frequency of 1KHz. The unit of sensitivity is dB/mW, and the other one thatis not commonly used is dB/Vrms, which is the sound pressure level produced bythe 1Vrms voltage applied to the headphones.

Highsensitivity means that the power required to reach a certain sound pressurelevel. Now the sensitivity of dynamic headphones is generally above 90dB/mW. Ifit is for the Walkman, the sensitivity is preferably around 100dB/mW or higher.

Themost intuitive performance of this parameter is: two pairs of headphones, theimpedance is 32Ω, a pair of sensitivity is 120dB, a pair of sensitivity is100dB, the sensitivity is 120, the louder the sound.