Active sound division is also called active frequency division. It is that the audio signal of the host is divided in the central processing unit of the host before being amplified by the power amplifier circuit. The principle is that the audio signal is sent to the central processing unit (CPU) of the host, and the central processing unit of the host audio signal is divided into low-frequency signal and high-frequency signal according to the frequency response range, and then the two separated signals are input into the amplifying circuit and amplified separately. The frequency division method is digital.

Passive sound division, also called passive frequency division, it is that the audio signal is amplified by the power amplifier circuit and then divided by the passive crossover, and then input to the corresponding tweeter or woofer. The principle is that the high frequency sound is filtered out by the inductance circuit, leaving the low frequency sound, and then input low-frequency sound to the woofer. The low-frequency sound is filtered out by the electrolytic capacitor and the high-frequency sound is left, and then it is input to the tweeter. The frequency division method is adjusted by a variable resistor.

Active sound division must be the main unit with active frequency division function or add a digital active crossover after the audio output of the main unit. Generally, the high-end models of Alpine main unit have active frequency division function. It is characterized by accurate crossover points and frequency division. The sound is clean after frequency division.

Active loudspeakers are actually used by many people. The small loudspeakers of the Walkman are active loudspeakers, that is, a set of amplifiers are added to the general loudspeaker box. When we want to use it, we only need the front stage and not the rear stage. The active internal uses an electronic sound division method, and eliminates the trouble of matching with the appropriate rear stage; the passive loudspeaker is a general loudspeaker with only one crossover network inside.

The active front stage is the front stage of IC, transistor, and vacuum tube that we generally see. It has an amplifying effect when the signal is input and then output. This kind of front stage can exert high dynamic performance, and the characteristics of each model are also different timbre. The passive front stage is simply a volume control attenuator, its output will be smaller than the input, but the tone rendering situation is less, usually only a slight difference, not like the active front stage amplifier is quite different .