I have a 2016 Macbook Pro 15" running macOS Sierra. The left speaker sounds muffled (it isn't outputting any treble) while the right speaker sounds perfectly fine.
For some casual debugging, I've done the following:
- Played with volume (no change)
- Used different audio sources (no change)
- Tried headphones (headphones work fine)
- Used Sound settings to change balance left and right, this magically made the right side sound just as bad. (This quickly lead me to believe it's a sound card issue)
- Used Applications > Utilities, Audio MIDI Setup to mute one side or the other and changed the format. This fixed the right side again confirming the sound card issue.
coreaudioand let it come back up. No audio at all after this.
- Reboot and reset pram, audio working as it was before (headphones good, left speaker muffled)
What else can I do to get both speakers singin' right again?