My Outback Onyx I notice the same thing – my driver’s side door sounds like there’s something loose in it.
Well, mine’s a premium and have noticed the driver door sound when closing “all windows up” is nothing like the others. From day one. No rattles or other anomalies but different. The passenger side front door sounds more like a Mercedes when you close it. Nice tight “thunk.” It sounds like a vehicle way above it’s class no doubt.
It’s not a problem, but I find it odd. Nothing loose, I’ve had the interior door panel off when installing speakers (actually all 4 doors) and made sure they’re all on intact. Again, just odd…
Edit: After looking like an obsessed old man opening & closing his car doors in the garage.. I’ve come to the conclusion it’s one of the door seals that’s the culprit. Whether it be the one on the door, or on the body opening is unknown. That’s the only thing I can think of that would give the “sound” difference between the 2 front doors that I’m hearing / feeling. Who knows, but that’s my thought.
