This is the sound producing self-excitation. You can check and judge from the following aspects:

1. Turn on the computer, stereo, play music, and hear an obvious clicking sound.

2. Click the small speaker icon in the lower right corner of the computer to display the volume adjustment slider. Use the mouse to drag the slider to slowly reduce the volume and listen to see if the clicking sound decreases with the music. If it is small enough and the clicking sound suddenly disappears, the fault is with the audio system.

3. To verify the above judgment, unplug the audio cable and use headphones to monitor. There is no clicking sound from loud to small, which proves that the above judgment is accurate.

4. Restore the first step and slowly reduce the volume control knob on the speaker. If the situation is the same as turning down the volume on the computer, the fault is inside the speaker. If the volume is turned down to the minimum and the clicking sound disappears along with the music, then there is a problem with the speaker's input cable. The reason is that the shielded wire is not used, which can be solved by changing a shielded wire.

5. Internal audio failure. When the volume is reduced to a certain level, the clicking sound disappears, indicating that there is no self-excitation when the signal is small. It is because the internal power supply voltage of the speaker cannot supply current at high volume, causing self-excitation. When turning on the machine, focus on checking the power supply voltage. Use a multimeter to monitor the voltage and you will find that the voltage fluctuates with the clicking sound. Focus on checking the filter capacitor, rectifier diode and other components. If one diode is open circuit, full-wave rectification will become half-wave rectification.

Check the power supply section carefully, replace the failed components, and the general fault will be eliminated.