Distinguish between active and passive speakers
        ActiveSpeaker is also known as "active speaker". Usually refers to speakers with power amplifiers, such as multimedia computer speakers, active ultra-low speakers, and some new home theater active speakers. Since the active speaker has a built-in power amplifier circuit, the user does not have to consider the problem of matching with the amplifier, and it is also convenient to drive directly with a lower level audio signal.
        In addition, there are some professional recording monitors with built-in amplifier circuits and electronic crossover speakers with built-in electronic crossover circuits and amplifiers.
        Active speakers are now mostly used in the field of computer multimedia, and some occasions with special needs (such as keyboard speakers) generally have lower output power, the volume cannot be turned on very much, and the circuit on the amplifier is not too particular. It is a simple sound system.
        Active speakers usually include parameters such as the output power of the built-in amplifier, input impedance, and input signal level. Active subwoofers also specify the frequency characteristics of the input signal (such as full-band signals or low-frequency signals), low-pass filter characteristics and other parameters.
        PassiveSpeaker is also known as a passive speaker. Passive speakers are the common speakers that we usually use without internal amplifier circuits. Passive speakers do not have amplifiers, but often have a crossover network and impedance compensation circuits.
        Passive speakers are generally labeled with parameters such as impedance, power, and frequency range.