Such problems can also cause the speakers to produce a popping or crackling sound. However, there are some steps that can be taken to diagnose and repair these problems.
The first thing you would need to do is to find the source of the problem. There can be many things at fault, such as cables, audio amplifier, or speakers. Make sure that everything is properly connected between the speakers, stereo, and the amplifier.
Disconnect the wire that connects the stereo and amplifier, but do not unplug the cable connecting the amplifier to the speakers. If the problem still persists, the amplifier might be at fault. But if the problem is solved, simply disconnect the wire from the radio. If the problem still persists, then the connecting cable probably needs a replacement.
The stereo system also won't work if there is a loose or missing connection. Check all the cables of the stereo, amplifier, and speakers separately and ensure that they are properly connected. Torn, pinched, or exposed cables can also be a reason for the system to be defunct.
If there is not enough power supplied to the speakers, they will not produce sound. Speakers that are installed by the car company work fine with the store-fitted audio system.
If different speakers are installed, they might not work due to compatibility issues, or may need more power to operate. Check their power supply by using a power meter. If they are receiving power but are still not working fine, the power provided may not be sufficient.
A blown fuse also can be a reason for the stereo to be nonfunctional. Refer to the car owner's manual and ensure if all fuses in the fuse box are intact. If they are fine, you need to check if the car's stereo system has its own fuses, which can be possible in case of some systems. If you find a faulty fuse, you need to replace it with a new one.
There also are chances of the speaker being faulty. You may check a blown speaker by an electric meter. Ensure that there is no power supplied to the speaker; set the electric meter to show "ohms". Place one meter lead on every terminal point. If the speaker is fine, the meter will display 1.0 ohm, but if it is blown, the meter will read infinite ohms.
A simple way to check a blown speaker is to place your hand on it and feel if there is any vibration and thump coming out at high volume. If the required thump is not felt, the speakers are blown.
If the speakers are not mounted in a correct manner, they may cause problem by producing a buzzing sound or vibrating. Such problems can be solved by simply turning the mounting screws a bit tighter. You can also place a piece of rubber between the speaker frame and the car interior.
If any of these mentioned tips don't seem to work, you probably need to take the help of a car stereo technician.