Active wall mounted speakers, to talk about what is an active speaker, we must first talk about the composition of the audio system. The simplest audio system consists of 3 links: audio source, power amplifier and speakers. The sound source refers to sound playback equipment such as radio, deck, CD player, VCD, DVD, MP3, etc. For a computer, both the CD-ROM and the sound card are audio source devices. Generally, the output signal of the audio source device is small, about hundreds of millivolts to two volts. If it is directly connected to the speaker, the sound may be very small or even silent at all. And because the impedance of the in-wall speakers is generally very low, most of them are between 4 and 8 ohms, and the impedance of some specially designed speakers is even less than 2 ohms in certain frequency bands, which is close to a short circuit, which can easily overload the audio source equipment. It may even cause damage to the audio source equipment. Therefore, a first-level power amplifier (referred to as power amplifier) must be added between the sound source and the speaker to amplify the weak signal output by the sound source to enough power to push the in wall speaker, so that the speaker emits enough volume. At the same time, the power amplifier has a high input impedance (usually tens of thousands of ohms) and a low output impedance (a few tenths of an ohm), which can play a buffering role between the audio source and the speaker, which will not overload the audio source equipment, and can Push the speaker easily.
