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Detailed introduction to the function and composition of active speakers

Release time：2021-11-12

To talk about what active speakers are, we must first talk about the composition of the sound system. The simplest sound system includes several links: sound source, power amplifier and speakers. Sound source refers to sound playback equipment such as radio, cassette, CD player, VCD, DVD, MP3, etc. For computers, optical drives and sound cards are both sound source devices. The output voltage of general sound source devices is relatively small, ranging from hundreds of millivolts to two volts. If it is directly connected to the speaker, the sound may be very small or even silent.

And because the impedance of the speaker is generally very low, most of it is between 4 and 8 ohms, and some speakers with special designs have an impedance of less than two ohms in certain frequency bands, which is close to a short circuit, which can easily overload the sound source device, and in severe cases may even cause damage to the sound source device. Therefore, it is necessary to add a power amplifier (referred to as power amplifier) between the sound source and the speaker to amplify the weak signal output by the sound source to a sufficient power to drive the speaker, so that the speaker can produce a sufficient volume.

At the same time, the power amplifier has a higher input impedance (usually tens of kiloohms) and a lower output impedance (a few tenths of an ohm), which can play a buffering role between the sound source and the speaker, neither overloading the sound source equipment nor easily driving the speaker. Functional effect Generally, each link of Hi-Fi audio is relatively independent, and a complete audio system can be formed through the connection of various connections.

Next article: How should we judge the quality of the speaker system?

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