How to protect the speaker？

Every effort is made to maximize the perceived loudness emitted by the speakers of portable devices, and care needs to be taken to avoid damage to the speakers themselves. These small transducers can only handle so much volume. There are two main aspects of speaker protection available: larger film offset and higher treble ring temperature.

A typical speaker profile clearly shows the physical limits of the film's movement, especially in the downward direction. The audio signal is not allowed to be too strong, otherwise it will cause the vibration element to contact the fixed pedestal assembly, or cause the suspension material (ring or spring) to be overstretched. In addition, the RMS value of the audio signal speaker is not allowed to be too large, otherwise it will cause the voice coil to overheat. Overheating of the voice coil will deform the circle of the coil tube, causing friction with the magnet or the edge of the pole sheet. Moreover, the high temperature in the loudspeaker voice coil will also cause its electrical insulation performance to deteriorate, which will short-circuit the turns of the voice coil, thereby reducing the voice coil impedance and overloading the amplifier. Too high a voice coil temperature will also heat the permanent magnet, which may cause it to demagnetize.

Techniques used to prevent speaker damage include: automatic gain control (AGC) for input signal amplitude and/or supply voltage, dynamic range compression (as described earlier), hard limiting, flexible clipping, and amplifier output overmeasurement. The disadvantage of these techniques is that they are feedforward methods and do not sense the actual speaker basin offset, voice coil temperature, or speaker impedance (which changes proportionally with temperature). More complex protective mechanisms such as thermal feedback are expected in the future, but the current conventional approach is one or more of the protective mechanisms mentioned above.