Sound Proofing Project-Phase 2: Doors

[travisgarrison]

Phase 2: Doors
- Materials:
- 1/2" Closed Cell Foam (like Ensolite) ~ 9sqft
- 1/4" Closed Cell Foam (like Ensolite) ~ 1sqft
- Polyfil
- Spray adhesive 92

- Tools:
- Ruler or measuring tape
- Phillips Screwdriver #2
- Phillips Screwdriver #1
- flathead Screwdriver (w/tape over the end)
- Exacto Knife
- Scissors
- Box Knife
- Latex gloves

Goals: The total project should be under $100, under 50lbs, reduce road noise by 3-7dBA and eliminate rattles

Intro: Unfortunately Honda did not do much sound dampening with the Insight. This was probably a combination of cost saving and weight restrictions. Unfortunately this means that at highway speeds the Insight is one of the noisiest cars many of us have been in. Honda did absolutely no sound dampening in the doors and for that reason they are number two on our list to dampen. Comparatively, this part is considerably easier than Phase 1.

Step 1: Prep
Follow Kevin Dougherty's instructions (Pulling an interior door panel) to remove the door panel. Repeat with the right door. You will then want to clean all the door surfaces. Do not remove the weather seal on the doors. We will be putting Ensolite right over it and it will work as an adhesion surface.



Step 2: Spray Adhesive
Using the spray adhesive, spray down the entire door areas that you will be adhering ensolite to. Do not spray the glass or areas where the door panel will not cover. Spray a little directly behind the hole where the speaker is placed.

**Repeat Step 2 with the right door while you're waiting for the adhesive to setup on he left door.

Step 3: 1/2" Closed Cell Foam
Once the adhesive has set up at least 5 minutes, cut out a 6" x 7" square and place it behind the hole where the speaker will go. This piece will only do minimal sound deadening and is primarily to give you a crisper sound on your speakers. Essentially it prevents sound waves from your speaker from bouncing all around inside the door and distoring the sound. Make sure you remember to spray on the adhesive also on the ensolite.



Step 4: Polyfil
This step is only if you still have the weather seal in place. Skip it if there is no moisture seal. In the middle of the door the moisture seal has a pocket. As you are putting Ensolite over this pocket, stuff it with polyfil. It will give you just a little bit more sound dampening (albeit not much).

Step 5: 1/4" Closed Cell Foam
The rest is pretty straight forward. I would still work in strips of no more than 10" x 18" but if you're feeling cocky then you could probably get it in one 18" x 36" sheet. Again, you have to spray the ensolite with the adhesive as well as the door surface. Do not put the closed cell foam over the holes for the pop-pins. It will cause you to not be able to pop them back in.



Step 6: Put it all back together
Follow the opposite order that you followed for taking the door panel off. Make sure to tighten the screws down well. This will prevent rattles.

Results: A crisper sounding door speaker and no more rattles. Road noise from the doors should be reduced. The door also has a better sound when closing (although that has never really mattered to me).

**Note: If you find out that you had a little overspray of the adhesive just use your fingernail and it comes off real easy.

Upcoming:
- Phase 3: Front Wheel wells
- Phase 4: Floors and firewall
- Phase 5: Rear wheel wells

[jf_cole]

I tried this at the weekend, but as it was raining, I took the doorcard inside and mounted the material to the inside of this.

I found the speakers gave a better sound and at low speeds it was quieter, but at higher speeds this was negligable. Cant wait to try the rest of the car.

Im using mousemats (foam backed) I got for free, a glue gun and scissors. Cheap and easy.

Boot area next.

[travisgarrison]

Good deal. I think that I've found that no one of these phases makes a huge improvement but together they do change things. The doors biggest advantage was more of the speaker improvements. I had the same results of highway speeds only experiencing the lowering of the tone of the noise rather than the loudness of it.

The biggest single improvement I got was from the rear wheel wells and spare tire compartment (Phase 1). This was because it greatly reduced road noise and also smoothed out the bass response I get from my 10" sub mounted into the spare tire compartment.

[Gordo]

Nice work on sound abatement. You have approached this project in a very methodical manner. Plus you are working on all the right places.

Another product which works well on large panels like door skins and front fender insides is self adhesive asphalt based dampening. Most people know it by its proprietary name: Dynamat, however, less expensive forms are B-Quiet, Brown Bread and others. It is designed to dampen the vibration of the panel... not prevent sound transmission.

The key to using this product is using your knuckles to tap the external skin as you apply. You can immediately source where the most vibrations occur and sticking a few pieces of Dynamat on the opposite side has the effect of quieting the whole panel.

Too often you see guys paper the whole inside of a trunk or body cabin. This is way overkill. Plus it is very heavy stuff. A couple of 12x8 pieces inside a door skin gets 90% of the job done.