Chosen Solution
I have done no repairs to my Macbook Air since I bought it. Just last night, the speakers started becoming muffled and it was crackling. It went back to normal and when I turned on the laptop this morning, the left speaker stopped working. The headphones work fine, I can hear from both sides. I don’t know if this is a software or hardware issue. I have tried balancing the audio in system preferences and many other methods but I still haven’t got a fix for it.
Using the balance control allows you to help isolate which speaker is failing. If the speaker is working now I would leave it alone. What likely happened was some sand orpine grit got into the speaker jamming up the voice coil from the fixed magnet core. Here’s a bit more: How Do Speakers Work: Understanding Audio Reproduction MacBook Air 11" Mid 2013 Left Speaker Replacement MacBook Air 11" Mid 2013 Right Speaker Replacement
