1. No sound at all – This might be a result of a software or a hardware issue. If restarting your computer a couple of times or tinkering with settings in System Preferences doesn’t seem to work, you might have a hardware problem. Usually, no audio is a sign of water or physical damage to the speakers. It can also be a result of a wiring issue that might have occurred due to an impact
2. Crackling audio or noise emanating from the speakers – Again, this is a common symptom of laptops that have faced liquid damage. When water seeps into the speakers, it might work to corrode the wiring or intricate components in the speaker which might cause the generation of noise. Make sure that you are facing audio issues in all apps and not just selected ones.