Speaker troubleshooting

Open circuit fault: The resistance between the two pins is infinite, which is silent in the circuit and there is no sound in the speaker.
Cone rupture fault: This fault can be found by direct inspection. The speaker with this fault needs to be replaced.
Poor sound quality fault: This is a soft fault of the speaker. Usually no obvious fault characteristics can be found, but the sound is not pleasant. The speaker with this fault needs to be replaced.
Under amateur conditions, the detection of speakers can only be done by audition inspection and multimeter inspection.
The audition inspection method is to connect the speaker to the output end of the power amplifier and subjectively evaluate its quality by listening to the sound.
Using a multimeter to detect the speaker is also rough.
Measure DC resistance: Use the R*1 gear to measure the DC resistance between the two pins of the speaker. Normally, it should be slightly smaller than the impedance of the nameplate speaker. For example, the measured resistance of an 8-ohm speaker is normally about 7 ohms. If the measured resistance is infinite or much larger than its nominal impedance value, it means that the speaker is damaged.
Listen to the sound: When measuring DC resistance, remove the pin of one test rod intermittently. You should be able to hear the speaker make a sound. The louder the better. No such sound means that the speaker voice coil is stuck.
Visual inspection: Check whether the speaker has a cracked paper cone.
Check the magnetism: Use a screwdriver to test the magnetism of the magnet. The stronger the magnetism, the better.