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How to add sound proofing MOD

66K views 88 replies 24 participants last post by  rlouie  
#1 ·
I had some minor surgery last week so my wife got to drive me to and from my appointments. The hospital was an hour away so this was the longest my wife has driven the Crosstrek since we bought the car. Her first comment was how quiet the car was. I have been adding sound proofing a little at a time as I do other mods and remove interior panels. Since it has been ongoing I guess I haven't noticed an immediate difference until My wife pointed it out. Here are some of the things I've done along the way.

When I installed the Kicker speaker upgrade I lined all 4 doors with Dyna Mat completely covering the inside of the doors and plugged all holes in the doors.



I had enough Dyna Mat left over to completely cover the inside of the rear hatch.



And used the rest of the pieces to line the spare tire well.

 
#2 · (Edited)
Then I found this Frost King Duct insulation at Home Depot and started to add that as a cheap alternative to the rest of the rear cargo area. And on top of the Dyna Mat in the spare tire well.


 
#3 · (Edited)
I removed the back seat and added some insulation around the gas tank and below the seat back.


 
#4 ·
Thanks for the pics!

You might want to add a layer of sound absorption material as well. Dynamat type material doesn't do much to absorb noise... they reduce the vibration of the surface it's attached to and block a little noise. Have a look at some closed cell foam or heavy felt like material to defuse or reflect the sound before it gets into the cabin. I added some closed cell foam (free carpet underlayment from a local carpet shop) to the spare tire well area and it made a heck of a difference. I didn't use any Dynamat-type material on the metal as I'm worried about the possibility of water being trapped between the Dynamat and the metal surface causing it to rust out - being on the Wet Coast of Canada, you have to be worried about water...
 
#5 ·
I agree and have been looking for some jute carpet pad material to line the rear wheel well and quarter panel area little more. There already is sound proofing material on the back of the wheel well plastic trim but not much.



I'm not too worried about the Dyna Mat material in the 4 doors because it was designed for that type of installation and has a solid rubber layer to dampen vibration not an open cell construction which could trap moisture. The Frost King insulation is more of an open cell foam so I used that in the interior only. The sound dampening properties really does help cut down on road noise. If you tap on the sheet metal panels particularly around the spare tire well and the rear quarter panels you can hear how any road noise must be amplified. I didn't use the insulation on certain areas because I could hear how solid and reinforced the metal was when tapping the panels. This is probably the "safety cage" area designed by Subaru to protect the occupants.
 
#6 ·
I found trying to find jute locally harder than going to a local carpet store and getting that underlayment. The underlayment I got is similar to the look of the jute in the doors but about twice as thick and four times as dense.

My plan is to fill those cavities behind the plastic mouldings with a layer of underlayment as well as some Dynamat type material to reduce the vibration of the panel. I did that with the front doors and found that the noise has been reduced enough for me to drive with my stereo set to a lower volume level!
 
#7 ·
VERY NICE Gt-Tom! Wow what a lot of work!! I just did the four speakers in mine, but took it to a great installer @ my local Best Buy and let him install the Dynamat and the tweeters/crossovers to the Polk Mm6501's. He did the doors and the back hatch for me and it did make a big difference. We haven't done the rear spear tire area yet. It did help a LOT! Will probably do about as much as you did to yours for the "ultimate" sound deadening.
 
#9 ·
No problem..... this was meant to be shared with all :)
 
#10 ·
Nice job. As previously said, you should look into some other material that is sound adsorbing as well. Dynamat will help but it's really more for vibrations not sound absorption. Was planning on using MLV along with some dynamat/b-quiet/etc. to do sound deadening. With the weather getting colder it will probably wait till the spring/summer.
 
#11 ·
*Very* nicely done GT-Tom. If you still on this forum, I was hoping you could answer a couple of questions please. Did you have any problems taking panels off? How much of that stuff did you end up using and do you know how much extra weight you added to the car? And lastly, did you do the rear doors as well? Thanks for sharing your setup.
 
#14 · (Edited)
No problem taking off the door panels. Actually harder to put them back on if you put the DynaMat too close to the plastic grommet holes. I think I used two large packs of the Dyna Mat. It wasn't cheap maybe $100 each but I had the door panels off already to do the speakers and only plan on doing it once. There was enough pieces left over to do the rear hatch and the spare tire well. The Dynamat is a very dense rubber pad and does add some weight. The extra weight in the doors makes the doors feel substantial and they close with a nice high-end car Thunk instead of the tinny twang of the factory set up. The added weight can be felt in the rear hatch too. The hatch opens more slowly and closes better. Before adding the Dyna Mat to the hatch sometimes the the hatch would not close all the way whe you slam it shut because the car is so air tight. Definitely closes the first time now. I only covered the inside panel of the doors (particularly blocking all open holes on the inside.) and did not put anything on the outside skin of doors or on the bottom of door.
 
#13 ·
Wow! Looks like you really did a nice job.. The great part is that you only need to do it once and it will last the life of the car. One thing that I would mention is to be cautious when plugging holes in the doors. There are drain holes in the bottom of the doors and they must be left open. If you plug those hole the doors will rust from the inside out. It's impossible to build a waterproof car door as long as it has windows that roll up and down. The doors are built so that water just runs through them. It comes into the interior of the door around the glass and drains out the weep holes in the bottom of the door. I've actually heard water slopping around inside doors before, it seldom has a happy ending..
 
#16 ·
Thanks for confirming it for me. Seeing that you didn't mention rear doors I'd assume you didn't touch those. I haven't taken panels off before but after seeing a few videos it doesn't seem like big of a deal. And I can see how putting it back together could be trickier, hitting all the plastic clips I guess. Did you need a service manual for any of that work? Thanks again.
 
#18 ·
I did all four doors. The Kicker Speaker upgrade includes the front and rear speakers so I did Dyna Mat on all the doors while I had them apart. I didn't use a manual, there are screws under the little flap of the door pull pocket and behind the door handle I think? Then you can pull off the panel starting with the corner by the speaker. You are suppose to use a trim tool to pop the grommets loose but I never could find each grommet so just pulled and it works. :)
 
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#21 · (Edited)
I removed the plastic barrier. (You can see Subaru attempted to reduce noise by using rubber pieces over the large holes in the door panel). The DynaMat is self adhesive and the purpose is to adhere the mat completely to the metal surface. You are suppose to use a small roller and try to get the mat to stick in all the nooks and curves in the steel door panel. As I understand it, the rubber mat absorbs the vibration channeling it to the aluminum outer surface and reflecting it back to the steel surface and canceling out the noise. Putting the mat over the large open holes is not canceling vibration but obviously blocking road noise from entering the inside of the car.




 
#22 ·
Great pics..... I've been thinking I might start in a a simple area like the spare wheel area. Is that an area where a lot of road noise creeps in? In your pic of that area it looks like you put the dynamat in some very select specific areas. Is there a reason for those areas? Where you put the Frost King stuff covered a much larger area. I'd probably just try the Frost King to start. Not sure I have the nerve to tear the panels off the car when it's so new lol. The spare tire area does look do-able though


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#27 ·
If I can chime in here, first off this is an excellent thread, how much space did you lose in the spare tire area? I pulled it out today to test and the rod used to clamp the spare down is petty tight as is. After your sound deadener was installed did you find it difficult to clamp the tire? Like above, I plan to start small and this is the first area I will test.
 
#28 ·
No problems . The insulation doesn't take up any room. Installed the spare tire without trouble :).
 
#29 ·
I did add some last night. I plan to do the speaker upgrade and bought 2 speakers but found I will need to modify or buy the adapters to make them fit. I used the opportunity to add some dynamat to the doors as well as the spare tire area. I can notice a difference already in the sound inside as the vehicle absorbs bumps. It sounds similar to being in a recording sound booth as the sound is eliminated immediately. I can also tell the difference in closing the front doors over the rears. The difference is similar to a hollow metal door versus an insulated metal door. I will continue to add as I go and I think I will heavily attack the floorboards as the last piece.

Thanks Tom!
 
#33 ·
Nope... Nice and quiet :)
 
#34 ·
I'm starting this project tomorrow night in my friends heated garage. Purchased a number of the items listed in sea-scooby's thread.

These are them:
http://www.amazon.com/gp/product/B002QG1P6E/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
Dynamat 10455 18" x 32" x 0.067" Thick Self-Adhesive Sound Deadener with Xtreme Bulk Pack, (Set of 9) : Amazon.com : Automotive
http://www.amazon.com/gp/product/B0007WTE08/ref=oh_details_o00_s01_i01?ie=UTF8&psc=1
5 pc. No-Scratch Tools for Removing Fastener & Molding : Amazon.com : Automotive
Amazon.com: Mountain Mist Fiberloft Polyester Stuffing, 3 Pounds: Arts, Crafts & Sewing

Not exactly sure how or where the sleeping pad foam and polyfil insulation will fit... But it'll be a fun project!

Will post pictures of my progress soon.
 
#36 ·
Hey Tom-

Where did you get the Frost King stuff for the spare tire area? I was at the Lowes in Amherst today and couldn't find any



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Really? I found it in the either the weather strip area or in the duct pipe area. Most likely the duct piping area. It's also pretty easy to find at Home Depot. Maybe they are sold out with the recent cold snap ?
 
#39 ·
You are right jj. I checked Lowes this morning and couldn't find it either. Definitely try Home Depot. That must be where I got from last time.
 
#46 ·
If you have a CVT, it already has some factory sound dampening under the hood using a pressed cardboard type of material... To improve this, you can probably remove the plastic clips and cut pieces of closed cell foam or some Thinsulate material (or both) into the cavities and then put the factory dampening back in place. I would just test the material with a strong hairdryer or a heat gun first to see if melts easily. CLD might be used if it didn't have the cardboard material as an interface between the two.

If you have a manual, you can order the factory sound dampening. From what I read, it's a makes a big difference on the MT cars.
 
#45 ·
Thanks for posting Tom. I was considering the same materials before finding your post. Your info is very useful.

I have two questions for anyone considering doing this:
Have you considered Best Buy or a Subaru dealership for the install?
Are there any warranty issues we are overlooking?

I don't know if I want to tackle this myself. I've done two interior swaps before, but never on a new car. Going to Subaru might be cost prohibitive and Best Buy quality can be hit or miss sometimes. But they both guarantee their work, which is nice.

Quick note, if you DO decide to order the Dynamat from Bestbuy, make sure they price match Amazons price because it's $110 cheaper for the 24x48 9 pack extreme kit ($290 vs $400).
 
#47 ·
In my experience, dealerships never want to do anything that isn't from the factory or sold at the dealership. So, you might have a hard time to get them to do it - also, since they have limited or no experience in doing the work, you'll probably end up paying a premium price for sub-optimal work.

Best Buy typically has people who are starting out in the business doing the work. While they are probably more experienced than the dealer, at least the dealer will know how to properly disassemble the plastic panels.

If I was going to get someone else to do the work, I would pay a bit more and get a good audio shop to do the work.

The only warranty issue that I could think of is the Dynamat material, or anything that sticks to the metal frame, might trap moisture next to the metal or prevent any excess moisture from either evaporating or draining out of the chassis. The extra moisture might cause rust... Of course, there is always the possibility of the installer damaging various parts as well during the install.

Guarantees are only as good as the people who are willing to stand behind them as well as what does the fine print say. Most car guaranties are betting that you won't keep the car for a long length of time and will probably trade it in after 3 to 5 years...

I would use a Dynamat type material over Dynamat as the price difference can be large (even larger than the difference between Best Buy and Amazon) and all Dynamat type material essential perform a very similar job in reducing the vibration on the material it's attached to by increasing it's mass.