I have a Impreza RS SW 05 & since day 1 I have been having this vibration/rattle noise. It almost sounds like when a speaker is blown but hell I hardly have the radio on. I took it to the dealer & they told me it was the seat buckle hitting the pillar, techs repositioned the seat buckle, I'm not an idiot that I couldn't have done that. Well noise is still there & I'm taking it in on Mon. for a replacement of a seat cover. I don't want to seem like a ***************, but should I insist they take off the panel this time. Now mind you it's not there all the time but when I go over rough roads it's there & don't tell me to stay off those roads because I should be able to drive my car anywhere.

#1. Have you been driving around with the windows open? In my STi the passanger side seatbelt will rattle around and make noise with the window open. The tech wasn't completely BSing you on that one. It's such a small car that there is very little room between the door and B pillar.

 

#2. With the door open, try lightly hitting the door panel and listen for the noise. You should be able to pin point a location this way.

 

Keith

I just went through this on my 2000 Legacy GT wagon. I too thought it was the seatbelt buckle but the noise was present even when the belt was buckled in. I could at times bang on the door panel with the door open and get a similar sound. Finally, after no less than three attempts at finding the noise by the dealer, the tech took the door panel off and tapping on the interior skin isolated the noise to the window motor rattling against the interior "skin" of the door. He placed a bit of foam behind the motor as a trial fix and noise is no more! I'll ask him to use something with a little adhesive to insure that the fix is permanent. Good luck.

I had a rattle in my passenger front door.

 

The speaker was loose.