Vigilant

I'l try to out it back again and simulate it again, this time I'll take some noise and FFT measurement.

Yes Stock exhaust. That picture is for illustration only. Btw, the drone I'm talking about is nowhere as serious as those aftermarket setup but at certain engine rpm and at idle you can "perceive" more boominess in the cabin. You know that surround , bassy , echoish kind of sound.

I wonder if the close proximity of the exhaust to one of the rear wheels have something to do with this.

After fixing the trunk , had some leftover MLV and I suddenly had an idea of putting it in the rear wheel arch. If I can block the noise at the source, then it would be more efficient right? Removed the wheel arch liner and placed the MLV around 1/3 all the way from the bottom(see pics). What surprises me is that there is more drone than before. Help me understand this , how does placing a sound barrier on the wheel arch increase the drone, I can't wrap my head around that. It seems totally unrelated.

Just one layer, however the passat already came with a lot of "stock" vibration damper. It's pretty well deadened stock I guess. No the trunk vents were not closed. On hindsight I think I should have not place too much damping on the centre of the trunk where the exhaust pipe flows, especially when it already comes with stock vibration damper. Did you manage to solve it? Did you remove the vibration damper from the trunk? I'm thinking of trying to play around with how the spare tyre is mounted in an attempt to change the resonant frequency of the panels.

Hi need help from you guys who understands soundproofing and noise better. I've recently soundproofed the trunk and the floor pan of my VW passat. Used CAE equivalent of dynamat, CAE VB4.5 , 3M thinsulate. Firstly the road noise "seemed" louder but I'm guessing it is because I've brought the whole noise floor down too much and therefore accentuating road noise further. Secondly there seems to be pressure building up my ears and it's causing minor irritation whenever I drive. My guess is the deadening lowered the resonant frequency of the car panels too much causing it to resonate and drone. The drone is quite low frequency and it is not very audible. You can feel the difference if you turn on and off the engine of the car at idle but it is not heard, more "felt". Has anyone has this problem before? I thought it was the problem of my ears so i drove my wife's prius. The prius is noisier of course, but the cabin feels more "airy" and less "pressurized" and doesn't have that feeling that i have.