My left speaker isn't working?

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.