You can check System Preferences > Sound > Output > Balance
You might also try different sound/music files, as some are recorded mono to only one channel.
If that doesn't help, it might be a loose wire or a blown speaker.
You can check System Preferences > Sound > Output > Balance
You might also try different sound/music files, as some are recorded mono to only one channel.
If that doesn't help, it might be a loose wire or a blown speaker.