A speaker is a device that restores an electrical signal to a sound signal, and the authenticity of the restoration will be an important criterion for evaluating the performance of the speaker.
According to different sounding principles and internal structures, speakers can be divided into several types: inverted, closed, flat, horn, labyrinth, etc. The most important forms are closed and inverted.
The closed speaker is to install the speaker on the closed box, and the efficiency is relatively low;
The difference between the vented speaker and it is that it is equipped with a circular vent hole on the front or rear panel. It works according to the principle of Helmholtz resonator and has the advantages of high sensitivity, high power tolerance and wide dynamic range. Because the sound wave on the back of the speaker is also released from the phase guide hole, its efficiency is also higher than that of the airtight box. And the same speaker installed in a suitable inverter box will be 3dB higher than the low-frequency sound pressure obtained in a closed box of the same volume, which is beneficial to the performance of the low-frequency part.
So this is also an important reason why the inverter box is widely popular.