Wall fitted speaker is mainly composed of driver, vibrating plate, suspension system and backplane, which have different characteristics. It will be described one by one below.
1. Driver: it is equivalent to a heart of a flat speaker. The key point of the design of the wall fitted speaker driver is that its effective stroke is very small, generally no more than 2m / m2; Secondly, the voice coil should not be too heavy, otherwise there will be serious distortion. The design of wall fitted speaker requires light weight, small volume and large magnetic force of the driver. Sometimes, in order to improve the output, two or four drivers are used to increase the output sound pressure, and a better frequency response curve can be obtained by using multiple drivers. The use of several drivers depends on the size and weight of the vibrating plate area.
2. Vibrating plate: like human vocal cords, the vibrating plate of wall fitted speaker plays a decisive role in sound color, sound size and sound flatness. Therefore, it plays an important role second only to the exciter in the flat speaker.
3. Suspension system: the vibration principle of wall fitted speaker is completely different from that of general traditional speakers. The general traditional horn adopts the piston type vibration mode; The vibration of wall fitted speaker adopts the mode of random vibration, so the lowest resonance frequency of wall fitted speaker is not only one point, but more than a dozen points. Moreover, the driving point of the wall fitted speaker is not in the center, because the center can not obtain the maximum sound pressure and the smoothest frequency response curve, but in the best position of node vibration.
4. Back plate: the design of the rear shell of the wall fitted speaker must consider the opening on the rear shell to increase the diffraction of sound waves, because the wall fitted speaker is a wave type vibration. The back of the same wall fitted speaker will produce the same sound pressure (but different phases), so there must be a window to increase the sound radiation, so it has better directivity and is not affected by different sound effects due to the location of the listener.
