There have been some threads here on sound proofing, but they have been somewhat general so I thought I would post what I did that greatly reduced the noise level in the PM.
First-proper sound proofing isn't cheap, you can go to home depot and purchase roofing material, however this really isn't the same as purchasing a high quality dampener specifically made for automotive use like "Dynamat". I know this because I have done the whole gambit from Dynamat Extreme to Home Depot special roofing material. Going cheap helps, but it's still not nearly as good as buying the right stuff, and for the most part you only save 25% and you get 50% less effectiveness.
To truly sound proof your car you are going to need to decide how far and to what level you are tying to achieve. The PM is horrible in regards to noise, it's a big tin can, what you can you say? So the plan was to reduce it as much as possible and at the same time to be practical about it. I am doing a van conversion to a camper van, so unlike a business use, having the inside quiet is important for the long drives ahead.
Good sound proofing is basically a three step process:
1. Reduce vibration - using a asphalt or butyl (butyl superior)
2. Use an sound adsorbing foam (closed cell)
3. Use a barrier to trap sound (MLV-mass loaded vinyl)
So I began with the floor, since I was going to use a super thick rubber based floor over plywood to level it off for sprinter seat mounts I used a closed cell foam base and put 3/4 inch of material on top of the floor. This was more than enough to make a huge dent in the noise level. I could have taking a step further using MLV as a base, but that stuff isn't cheap and decided to skip it and just use foam layer, plywood, and the composite floor.
Floor
Legend Composite Floor $700
Plywood $60 (3 sheets0
Wood Floor Barrier $70
Trim Loc $100 (25 foot roll)
Msl stuff $50
Walls:
$350-400
38 square feet of Sound Dampener (RAAM Mat)
40 square feet of closed cell foam (Ensolite)
30 square feet of MLV with closed cell foam (1/8 MLV w/ 1/4 inch foam)
Plywood Base
Finished Legend Composite Floor with Trim Loc covering edge
Next step was to use a good quality sound dampener. Remember this reduced vibration, but really isn't a "sound barrier" per se. You have to though start with this as a foundation. I used 38 square feet of RAAM Mat and 3 yards of Ensolite (closed cell foam). This was enough to cover everything under the windows in my van and the doors.
You only need to cover 25-50% of the area to be effective, you can do more but you don't really need to.
Roof with RAAM Mat (this later is going to get covered so I did not get to crazy here)
This is the Ensolite foam (closed cell foam) This is to absorb the sound after you controlled vibration. I was happy with this but decided I even wanted to go further to really make the van quiet.
So I decided to do some MLV with closed cell foam. I had not used this before but knew from other forums this really is the only way to stop sound really well. I put it over the wheel wells, walls, and eventually did the doors. It's heavy, stiff, and expensive, but it really stops sound. You could skip the Ensolite step and just to a vibration dampener and do this and you will have a high end car like feel.
You must use a high quality automotive adhesive to clue down the MLV. Remember foam side to the walls glued to the Dampener you choose.
This picture is the wheel well through the process. This shows MLV on the wheel well and Ensolite and a layer of RAAM underneath both the Ensolite and MLV.
I taped the seams here with duct tape. Its totally glued down and these are all going to be covered anyways, but I wanted to do it best way possible. I had to do this in pieces due to the curve of the wheel well.
I eventually even did the doors. You could go crazy with this stuff. Did I get every little space? NO, but it's more than enough in my opinion. I am not making a competition SPL car. The MLV is now on the wall also. This stuff is HEAVY 1 lb a square foot!
End Result which all the panels looked like
So was it worth it? Well I spent about $350-400 in materials to do the bottom half of my interior. I can tell you it's super quiet! So much so that now the wind off the windows I can clearly hear and it would be useless to do more as the wind noise now exceeds any other noises I heard before. I am happy I did this. I would say it's similar to what my wifes Toyota Sienna sounds like inside now. I think thats a big deal, the PM van is a big brick and sound quality was not in it's design. For sure step 1 and step 3 are absolutely needed if you really want to make a difference. An added benefit is I have much better insulation now. I am still adding walls, a camper roof, and headliner so it's going to be even much quieter when that's done.
I still did not even do the front doors or rip out the front rubber flooring...this would make the PM super quite, but the noise in front wasn't bad, it was all teh stuff from the rear. I may eventually do the front, but did not want to take that all apart at this time.
Hope this helps has you figure out how to do your interior.
First-proper sound proofing isn't cheap, you can go to home depot and purchase roofing material, however this really isn't the same as purchasing a high quality dampener specifically made for automotive use like "Dynamat". I know this because I have done the whole gambit from Dynamat Extreme to Home Depot special roofing material. Going cheap helps, but it's still not nearly as good as buying the right stuff, and for the most part you only save 25% and you get 50% less effectiveness.
To truly sound proof your car you are going to need to decide how far and to what level you are tying to achieve. The PM is horrible in regards to noise, it's a big tin can, what you can you say? So the plan was to reduce it as much as possible and at the same time to be practical about it. I am doing a van conversion to a camper van, so unlike a business use, having the inside quiet is important for the long drives ahead.
Good sound proofing is basically a three step process:
1. Reduce vibration - using a asphalt or butyl (butyl superior)
2. Use an sound adsorbing foam (closed cell)
3. Use a barrier to trap sound (MLV-mass loaded vinyl)
So I began with the floor, since I was going to use a super thick rubber based floor over plywood to level it off for sprinter seat mounts I used a closed cell foam base and put 3/4 inch of material on top of the floor. This was more than enough to make a huge dent in the noise level. I could have taking a step further using MLV as a base, but that stuff isn't cheap and decided to skip it and just use foam layer, plywood, and the composite floor.
Floor
Legend Composite Floor $700
Plywood $60 (3 sheets0
Wood Floor Barrier $70
Trim Loc $100 (25 foot roll)
Msl stuff $50
Walls:
$350-400
38 square feet of Sound Dampener (RAAM Mat)
40 square feet of closed cell foam (Ensolite)
30 square feet of MLV with closed cell foam (1/8 MLV w/ 1/4 inch foam)
Plywood Base
Finished Legend Composite Floor with Trim Loc covering edge
Next step was to use a good quality sound dampener. Remember this reduced vibration, but really isn't a "sound barrier" per se. You have to though start with this as a foundation. I used 38 square feet of RAAM Mat and 3 yards of Ensolite (closed cell foam). This was enough to cover everything under the windows in my van and the doors.
You only need to cover 25-50% of the area to be effective, you can do more but you don't really need to.
Roof with RAAM Mat (this later is going to get covered so I did not get to crazy here)
This is the Ensolite foam (closed cell foam) This is to absorb the sound after you controlled vibration. I was happy with this but decided I even wanted to go further to really make the van quiet.
So I decided to do some MLV with closed cell foam. I had not used this before but knew from other forums this really is the only way to stop sound really well. I put it over the wheel wells, walls, and eventually did the doors. It's heavy, stiff, and expensive, but it really stops sound. You could skip the Ensolite step and just to a vibration dampener and do this and you will have a high end car like feel.
You must use a high quality automotive adhesive to clue down the MLV. Remember foam side to the walls glued to the Dampener you choose.
This picture is the wheel well through the process. This shows MLV on the wheel well and Ensolite and a layer of RAAM underneath both the Ensolite and MLV.
I taped the seams here with duct tape. Its totally glued down and these are all going to be covered anyways, but I wanted to do it best way possible. I had to do this in pieces due to the curve of the wheel well.
I eventually even did the doors. You could go crazy with this stuff. Did I get every little space? NO, but it's more than enough in my opinion. I am not making a competition SPL car. The MLV is now on the wall also. This stuff is HEAVY 1 lb a square foot!
End Result which all the panels looked like
So was it worth it? Well I spent about $350-400 in materials to do the bottom half of my interior. I can tell you it's super quiet! So much so that now the wind off the windows I can clearly hear and it would be useless to do more as the wind noise now exceeds any other noises I heard before. I am happy I did this. I would say it's similar to what my wifes Toyota Sienna sounds like inside now. I think thats a big deal, the PM van is a big brick and sound quality was not in it's design. For sure step 1 and step 3 are absolutely needed if you really want to make a difference. An added benefit is I have much better insulation now. I am still adding walls, a camper roof, and headliner so it's going to be even much quieter when that's done.
I still did not even do the front doors or rip out the front rubber flooring...this would make the PM super quite, but the noise in front wasn't bad, it was all teh stuff from the rear. I may eventually do the front, but did not want to take that all apart at this time.
Hope this helps has you figure out how to do your interior.
