We know that the characteristics of low-frequency sound waves are high sound pressure and long wavelength. Therefore, compared to medium to high frequency sound waves with prominent propagation directionality, the propagation of low-frequency sound waves has little obvious directionality or directionality; At the same time, when the speaker is playing (i.e., the diaphragm vibrates before and after), the air will form a "positive pressure zone" and a "negative pressure zone" at the front and rear edges of the diaphragm, as well as two identical frequency sound waves with opposite directions and phases.

So combining the above points, if the sound waves behind the diaphragm wrap around the front of the diaphragm and "meet" with the same frequency and opposite phase sound waves, the energy of the two will cancel out each other, forming a "sound short circuit", directly affecting the audience's listening experience; Moreover, due to the inherent high sound pressure and long wave length of the bass, it is easy to detour and propagate in an undirected (i.e. omnidirectional) manner. Therefore, the "sound short circuit" phenomenon of the sound waves during horn playback will be particularly obvious and prominent in the low-frequency part.

The best way to solve the problem of "sound short circuit" during the operation of the horn is to add a "barrier" around the diaphragm of the horn, which physically isolates the front and rear sound waves generated by the diaphragm from the pressure zone. The larger the barrier, the longer it is, and the lower the frequency of the sound waves that can be isolated. Therefore, the function of the speaker box is to first and foremost serve as an "infinite barrier" in length, locking any wavelength of sound waves behind the speaker diaphragm in the box, thereby avoiding the interference and cancellation of sound waves in front of the diaphragm by the sound waves behind it, thus solving the major problem of "sound short circuit" that seriously damages the quality of hearing.

Of course, for subwoofers, the box can play more than that. Each horn has its own specific resonance point (fs), at which a small amount of energy is required to cause significant displacement of the horn diaphragm, leading to distortion of the sound; Therefore, when playing subwoofers, they always strive to be as close to fs as possible without touching it, in order to achieve the relatively ideal low-frequency response while avoiding distortion, and fully tap into the frequency response potential of subwoofers. This is mainly achieved by adjusting the volume of the subwoofer box.

For the selection of panels, the main goal is to pursue better structural rigidity and reduce the resonance of the box itself, as well as to improve the final low-frequency sound quality by optimizing physical properties such as damping. Common subwoofer boxes include enclosed boxes and perforated (inverted) boxes. The former tends to have a solid and deep sound with a certain analytical power, while the latter also outputs forward the sound waves behind the diaphragm after inverted, overlapping with the same frequency sound waves in front of the diaphragm, giving the sound a stronger sense of force and speed.

Whether to use a closed box or an open box, players can choose according to their actual listening needs. If players want to achieve good low-frequency effects without having to toss too much, they can choose professional brand bass with a box. This type of product comes with its original box body, and the brand has already pre designed the volume and structure of the box body. It is made according to the appropriate box volume and quality of the board. After being connected to the power amplifier, it can directly output impressive low-frequency response, allowing players to experience less trouble and still enjoy the joyful low-frequency "fun".