Impressive sound results
Im trying to wrap my head around how you did this.
May I ask you some questions?
Is this 2 piece (front &rear)??
What thcikness??
How did you attach it to the hard top??
What is CLD??
Lots of questions! Happy to answer.
The headliners are two separate panels. I used 1/2" plywood, though at some point I'll redo them with 1/2" MDF for rigidity. The insulation is Rockwool, 3" thick (pick up the sound treatment kind, it says it on the label, got mine at Lowes), and attic heat shield which is, I think, between 1/4 and 1/2 inch.
The Rockwool is wrapped in 1mm plastic drop cloth. I have the insulation spray glued to the board, then the plastic stapled down over it. The heat shield I have on top of the Rockwool and on the opposing side of the plywood. Cloth is stretched over the side opposite the Rockwool.
It's attached to the rollbars with these beefy bastards:
Rollbar accessory clamps for things like lights. They're solid, and would probably hold up my weight.
When mounted the headliners are thick enough to put pressure against the top but not so much that the insulation is smushed flat. Flattened insultation doesn't work, the more compressed the less temperature and sound resistant it is, but the more pressure against the top the more resonance is taken out. If you whack your hand against the hard top it sounds like a drum (resonance), with the headliners on it sounds like I'm thumping a table. They aren't attached at all to the top itself, I didn't want to drill holes or harm the structural integrity at all. With this setup all I have to do is remove the panels from the clamps.
I'm super tickled about how well this works out. The color almost exactly matches the original interior of the hard top which I at first disliked but now I like how "open" it makes the Jeep feel inside. The sound reduction is so drastic it actually feels like a car. It's incredible. I've always loved riding in my Jeep but now it's even more appealing, with the windows rolled up the world gets tuned out. Even the engine sound is reduced.
CLD is constrained layer dampener, a layer of butyl rubber over metal foil. The rubber bends when the surface it's attached to flexes and resists the motion, reducing the vibration/resonance of the surface, which is the source of a lot of noise in a vehicle. You can just use a little on the biggest, flattest panels you have (floorboards, cargo space floor, hard top) or you can cover every square inch. It's EXTREMELY popular in the car audio world because it both reduces noise which intrudes upon your listening experience and helps to stiffen the vehicle surfaces which improves bass. Part of the reason I wanted my headliners to be removable was so that I could put CLD on later. I'll eventually have the entire hard top and every metal surface of the Jeep (including inside the doors) covered with CLD.
I also put heat shield under the carpets to reduce the heat transfer from the transmission tunnel and help noise a little bit.
I have a few other noise-reduction projects that I'll do over the next few months, and you can get really crazy with it if you go down the rabbit hole, but the headliners and the CLD should be the biggest bang for the buck.
