Cabin noise

Guard Dad

Update:

I've now had a chance to put a few freeway miles on the Z since adding Raamat to the cockpit floor and I'm happy to report that a noticeable improvement has been achieved. The low frequency resonance coming from the foot well has been reduced sufficiently as to be a non issue. The car is in no way a luxury cruiser but it is now possible to listen to the sound system at normal levels and conversation can be conducted in a normal manner.

The take away is as follows:

If the Z's noise environment is a problem for you (and for many of you it is not) I believe that I have identified a straight forward three step procedure for addressing you concerns.

1. Apply Dynamat Extreme or Raamat to the hatch, wheel wells and door panels for a big reduction in road noise. I'd do this one again in a heartbeat.

2. Apply Luxury Liner Pro to the hatch and wheel wells for a further reduction in road noise. This stuff is heavy and not cheap, I liked the subtle improvement, but I'm not sure I'd do it again.

3. Apply Dynamat/Raamat to the B pillars (to about shoulder level) and to as much of the bare metal under the carpet as is possible, for a reduction in resonance from the front of the car. This makes a nice improvement but is only worth doing if you are at least doing step 1. Without step 1 the cabin is too noisy to notice the improvement from this mod. This requires removal of a lot of the interior and is probably only worth doing if you are gutting the interior for an audio upgrade or similar mod. The actual amount of Dynamat/Raamat is about 24 square feet which equals about 12 pounds.

It has been pointed out by others that Dynamat/Raamat is a resonance reducer and not an especially effective sound deadener and that a mass-loaded-vinyl (Luxury Liner Pro is a MLV) is necessary to achieve meaningful improvements. My experience would suggest that Dynamat/Raamat is very effective in the Z. It is thin so it doesn't complicate reinstallation of the interior trim pieces. It is easy to install and bonds well to the structure of the car. It weighs about 1/2 pound per square foot. MLV's are about 1+ pound per square foot and are intended to be installed over Dynamat/Raamat and as a system system weigh 1.5+ pounds per square foot. MLV's are 1/4"-3/8" thick and can complicate reinstallation of interior trim pieces. MLV's have to be glued to the car and sometimes getting a good bond on a irregular surface can be a problem. MLV's cost at least 2-3 times as much as Dynamat/Raamat. In my opinion the big payoff is in the hatch and if I was doing a do-over I would consider a double layer of Dynamat/Raamat in selected areas of the hatch and skipping the MLV.

If anyone has questions please post them here or PM me.