What kind of subwoofer can be divided into?

If you distinguish between built-in amplifiers, the subwoofer can be divided into active subwoofers with built-in amplifiers and passive subwoofers without built-in amplifiers. If the cabinet design is used to distinguish it, the subwoofer is the same as the general speaker. It can be divided into a sealed system (Sealed System), a bass reflex design (Ported System), a belt design (Bandpass System), and a transmission line design ( Transmission Line System) and so on. If it is distinguished by the direction of sounding, there are several kinds of sounds such as sounding toward the front, sounding toward the back, sounding toward the floor, sounding upwards, and making sounds on the left and right sides. If it is distinguished by a single action mode, there are two cells of push-pull type, two or three monomers of in-phase sounding type, one unit of one passive radiator, and the same phase sounding type. The most advanced subwoofer is built-in expansion machine, and also has a built-in bass equalization line, which can moderately attenuate indoor low-frequency standing waves to a certain extent, and achieve low frequency bands below 100Hz or 80Hz. Compare the flat frequency response curve. This subwoofer is ideal and the most expensive. Q What is a closed subwoofer? A: The box itself is sealed, there is no hole or gap in contact with the outside, and the woofer can be placed facing forward, rear, side or above. This kind of box is the simplest in manufacturing and easy to meet the quality requirements. Its advantage is that the transient reaction is fast, can withstand large power, and the volume of the box can be made smaller. The closed subwoofer is one of the subwoofers that are commonly seen on the market.