Hi, I'm starting a soundproofing project. I hope this thread and the pictures in particular will be helpful for anyone doing a similar build. My build is focused around lowering the ambient noise inside the car at freeway speeds, cost-effectiveness, and efficient use of materials.

The soundproofing in this car is textbook up until the wall behind the seats. Sound treatment is done in 2 steps: vibration dampening and sound proofing (source: sounddeadenershowdown.com). The vehicle package page gives you a good estimate of the materials you'll need, but doesn't give you much direction on where to apply it. Note that this is unrelated to the owner of the website, I just used it as a reference. The intended purpose of this thread is to detail the treatment process of the rear of the car in particular, utilizing the technique seen here, https://www.sounddeadenershowdown.co...unk-strategies, "Isolate the Trunk from the Passenger Compartment".

I will not be covering the floors and doors in this thread, as they are basic and you can learn all you need to know to successfully treat these areas from the website above. The problem area I will focus on is the back wall, bulkhead, and rear tray, and how treating these areas alone might, in theory, provide the same result as treating the entire rear wheel area and trunk with sound proofing materials.

The Theory:
Maintaining a noise barrier between the trunk and passenger compartment is what I am trying to accomplish. The reason for this is to save on materials. I will still apply vibration dampening material to the spare tire/fuel tank/rear tire area, and some to the trunk, but I will essentially acoustically seal the passenger compartment off from the trunk (source:https://www.sounddeadenershowdown.co...unk-strategies, "Isolate the Trunk from the Passenger Compartment")

Let's dive right in. I removed the entire rear trim and this is what it looks like from the front ...

and the back ...


After seeing for myself the body of the car, I had a better idea of how to tackle this problem. The plan is to run MLV on the rear quarter panels, and on the back wall behind the seats which will extend up and over into the rear deck area, flat. Then, I will simply try my best to make a continuous MLV seal. This will be done by applying MLV to the underside of the 3 tray trim panels. The MLV on these panels will extend past the panels itself towards the front, at which point it will slope down and be attached by velcro to the MLV coming from the front of the car to the rear deck. This address the middle of the car, but the corners are more intricate. For the corners I will be contouring the outside edges of the MLV on the 2 rear side trays to attach to the sides of the car with velcro.

I saw this as a more cost efficient approach as opposed to treating the entire back length of the car. I will post more progress pictures when I get going on the project.

 

Project is 95% finished but I don’t have any pics of the process. The car is pretty quiet now. My ears almost popped the first time I drove it because they got used to it being so loud all the time. Overall it was worth it.

i didn’t follow through with my method above, instead I applied MLV to the spare tire area and the back of the 2 plastic pieces separating the trunk. Also there is mlv behind center console and along the back wall. This got me a 80% seal and I’m happy with it.

the stock roll hoops are hollow behind the back wall, so it would be a whole process to get mlv mounted there albeit not impossible, so that might be on the agenda, since as of right now those are the two best places where sound can bleed through