Odd noise

Weird buzzing noise. Please help me identify.

Driving down the road at anything above 15mph seems to produce a buzzing noise from the rear decklid area. The noise isn’t constant, but it continues for several seconds at a time, then pauses, and will restart. Once the car stops, the noise goes away. Varying speed doesn’t impact the noise; it’s either there or not. The noise is best described as an insect flying against a window with the noise being wings hitting the glass. It's not an electrical noise (i.e. fuel pump). I think it's a vibration of sorts. Noise is unchanged with seats up vs. seats down.

The rear deck lid is notorious for making rattling noises. I would check out the rear lid and try and see if it moves around at all, or is rubbing. The sound you describe is a little different though. Could it be related to the rear speakers? If it is a very consistent noise, and is more buzzing than vibrating, my guess would be electronic potentially.

Do you have the H/K audio package? I know the amp is housed back there as well