The test uses a mobile phone Bluetooth connection to play cool dog music. When the volume is adjusted to 15 max, the sound will be stuck and distorted, which may be clipping distortion. If the signal level is too strong, beyond the allowable range (threshold) of the circuit, the signal will not pass smoothly, and its waveform will be cut off after a part of the wave signal enters the speaker, and its current passes through the speaker voice coil, because the DC component in the clipping signal cannot When the voice coil is moved, its electrical energy cannot be converted into mechanical energy, which generates a large amount of thermal energy, which causes the voice coil to heat up. If the clipping distortion is very serious, the direct current is large, which may damage the speaker tweeter.