I've been doing Car Audio systems for the better part of 30 years and have deadened and sound proofed several of the ones that had bigger systems.
I spend the time and money to do this this for a number of reasons.
1. Reduce resonate or panel vibration. I hate to hear a car drive by where it rattles to the beat, sounding like its going to fall apart.
2. Road Noise. I also hate trying to listen to a good SQ song like Hotel California or a good jazz song that has a lot of mids and highs, to show off that part of the system, but they appear to be washed out do to the road noise.
3. I like when I close a door, hood, trunk like or whatever, for it to have a solid Thump to it, not a thin almost a ringing sound from the thin metal vibrating...
With the 82 I got a few weeks ago, when I strip the interior, I think I'm going to use at least two different products.
1. A spray in, to coat the inside of the doors, fenders, bed bottom, under side of the cab floor, fire wall, etc..
2. Then a deadener sheet that you apply like a Dynamat product, but probably a brand called
SecondSkin...
I want this thing deadend and quite except for the Stereo and a bit of the exhaust note and Sounds from the bag valves maybe...
Whatever I mount the compressors to will get deadeded for sure.