My rMBP has worked fine since I got it brand new in 2012 but last night the audio on the right speaker plays distorted. It sounds muffled and more apparent with low tones and it happens with all audio. It's almost akin to a buzzing noise and it's really irritating. Headphones work and sound just fine when plugged in though. I'm not a speaker or audio expert but has anyone experience anything similar? Has my speaker gone kaput? I assume it's hardware related and maybe its just my speaker going bad. Seems strange to me that speakers would go bad approaching 3 years old. Advice?