Ive been trying to find similar posts to my problem, maybe I'm not describing/searching it correctly?
2011 A3 Quattro, 125,xxx miles
This "wobble/rattle" happens at low rpm when i'm just letting off brake and car is just taking off on its own, it also happens when im slowly going over a speed bump. I don't hear anything under regular driving conditions, only in take-off situations. you can visually see that this noise makes the accessory belts kind of wobble. I've included a youtube video that tries to capture this noise, its not easy to replicate but I am able to catch it about 5 times in this video, I should also note the noise under question doesn't last long possibly a few seconds. but you can hear it begin a fade in and out.
noise in video begins at
1min 8 seconds