Sound Deadening - Memorial Day Weekend(ish) Project!

After reading through dellrio’s thread about sound deadening and talking to him a bit through PM I decided to take a crack at it. I love my Prius C, and the road noise isn’t any worse than it was in my Scion tC, but that doesn’t mean it’s great. I am not sure what to expect at the end of this, but I am hoping for a decent amount of road noise sound reduction. And yeah, it will let me keep my stereo up loud without worrying about the city ordinances against loud noise (Tampa just passed one that if your car is audible 50 feet away you can face fines -and- jail time!).

I have taken my other cars apart to install speakers, stereos, run subwoofer wires, but nothing to the extent that I know this is going to be. I’m hoping that this guide, written as I go through the process, will help others who aren’t sure how to go about doing this or how well it will work.

In addition to sound deadening I am running wiring for a future amplifier/subwoofer. I do not plan on setting one up at this time but since I’ll have all the paneling off I figured I might as well run the wire.

As a note, I still have stock speakers as well!

First, here are all the materials I am using:

Sound Deadening:
- 100 feet of FatMat RattleTrap (2 50ft rolls) *
- Needle nose pliers with electrical tape on the tips **
- Flathead screwdriver with electrical tape on the tip **
- Philips Head screwdriver
- Socket wrench
- Scissors
- Tape Measure
- T/E TORX set (need E10 for the seats)
- Extension socket bits for dillers

If you are curious what comes with the RattleTrap, here it is:



Amplifier/Subwoofer
- 2-Channel line out converter
- EZPass Velco (to hold the converter up)
- 2 of Mediabridge Ultra Series Subwoofer Cable (15 feet):
- 50ft 18 guage remote wire

(I tried to link the Amazon pages for the equipment I ordered from there but the forums don’t seem to want to let me do that. So PM me if you want those!)

* I did discuss with dellrio about what type of sound deadening material to purchase. He used the FatMat brand FatMat (50mil) asphalt for almost all of the car, with some rattletrap on a door and higher-end local butyl to finish up. He double-layered the doors, roof, hatch, trunk area and some of the floor and used roughly 140ft. He suggested using the FatMat MegaMat butyl-based since it was a lot of work to put it in, and it’s a higher-end material.

So why did I end up with the Rattle Trap? A few reasons: It was (somewhat) cheaper, and I wanted to be able to stick it on my Amazon Store Card, so it was $180+shipping vs $230 + shipping. The other main reason is that I do understand butyl-based should provide better quality, BUT, dellrio used asphalt based and I know for sure he was definitely happy with it. So I decided to go with a proven winner. As for why the Rattle Trap over the FatMat, it’s almost twice as thick so I’m hoping I can finish up with only 100 feet and not really double-layer anything, we’ll see.

** The Toyota guide I saw said to use tape on the ends of the pliers and screwdrivers. The only reason I can assume is to prevent damage or scratching, which is good enough for me.

As a note:Each time I do anything I am first disconnecting the auxillary battery. For anyone who hasn’t looked for it, it’s under the rear passenger seat. Click in the two clips with a pen and they will pop out and you can take the cover off. I looked and wasn’t exactly sure what to remove, so someone can correct me if I’m doing it wrong. The negative cable goes down to metal towards the floor, I am taking the bolt out of that and then putting the cable in a plastic bag so it doesn’t accidentally touch the metal again. It does still spark when I unplug and plug it back in.




This will also reset a lot. Radio presets, time on the display, any mileage calculators on the trips (still has the total trip miles but not the information underneath), the climate settings, etc.

Anyway, here we go!

I will update this main post as I go. I currently have the four doors done and will be posting them shortly.

Day 1

I wasn’t sure how this was going to go so I decided to start with the rear passenger door. I figured that was the easiest to shrug off if something went wrong! As a note I did not have any trouble with cutting or applying the RattleTrap, I know people say it can be harder when it’s colder but it’s May in Florida and was 80 in my garage.

So for the two rear doors you take the panel off by:

- Popping off the black triangle piece up by the window. I used the flathead (covered with electrical tape) to pop the fasteners. There are two at the bottom and one on the side. Then I pulled it off and everything aside.
- Pop out the black fastener at the top of the door. I pushed it on it with the flathead again and was able to pop it out.
- By the doorhandle there is a circle piece, this has to be popped open. Under it is a philips head screw to take out. Do not bend the plastic piece back too far! I somehow did on this door (but not the others) and now it doesn’t stay closed. A small piece of black electrical tape is holding it shut.
- Pop the black door piece (where the window button is) off. I used the flathead screwdriver again and went around it to pop it up and then pulled it off (I did this on all 4 doors and didn’t break anything, whew!)
- Disconnect the cables attached to the piece
- Unscrew the two philips head screws underneath that.
- Pull the door panel off. Start by the speaker, then go across the bottom then up the two sides. Once the top ones are off on each lift the panel up and it will come out of the window pane and be loose. If any of the fasteners stay attached to the car pry them off with pliers and slide them back onto the panel.
- The doorhandle is still attached at this point. A guide I saw said to disconnect the wires, I didn’t like that. I popped out the whole contraption by pushing down on the pin in back, then the two sides and it popped right out.
- Take off the plastic cover on the door. I ripped this off on all the doors, the black sticky stuff is a pain though. Dellrio said he ended up cutting the plastic and leaving small pieces around the edge with the sticky stuff.



Now that the door is off I cut up the RattleTrap into what I thought could fit (lots of squares and small long pieces) and began to apply them.

You can see the door is two panels, I reached inside the openings and applied it where I could reach, it definitely doesn’t cover the entire inside though. As a note, dellrio did mention to me (after I had one door done so luckily I was okay!) to make sure you don’t apply it where the window comes down, or else you could have problems. I just did one layer flat against the back and it was fine.

Once I was good with the outer panel I worked on the inner panel, where all the wires are. The first two doors I actually tried to pop out as many of the wire holders as I could (pinching the back), but I gave up on the last two doors and just put put the rattletrap around them. I did pop out the speaker wire on all of them. You can cover the wires if you really want but that will make a huge mess in the future if any work needs to be done on them.

Any holes you cover up (fasteners for the handle, door screws, etc) make sure you cut holes so they can still get through! For the doorhandle wire I cut a slit in the rattletrap.



- Reconnect any fasteners or wires you disconnected inside the door!
- Re-attach the doorhandle piece that you popped out
- Drop the door panel back on, starting with putting it on the window pane
- Make sure the wires for the door that need to be connected can be reached
- Pop in all the fasteners on the door
- Put back in the three screws (two in the black door piece area, one where the doorhandle is)
- Re-attach the wires to the black piece and pop that back in
- Re-attach the black fastener at the top (this one was a little weird - pull the circle away from the rest of it, then place the circle over the opening and push the fastener in)
- Re-attach the black triangle piece.

Done with the rear doors! If I’m missing anything I’ll write it in if I remember.

Day 2

Front door day!

To remove the front door panels:

- Pretty much the same as the rear. There is no black triangle piece on those. There is no black fastener towards the top.
- Pop the black panel off with the switches (there are more hooks on these than the back door ones), pop open the circle piece by the doorhandle. Remove all three screws.
- Remove the wires attached to the black door piece (there are bigger ones on the front doors since they have more switches)
- Pop the panel off the same way, starting at the speaker, working up, picking off the top
- The doorhandle part was harder to pop off on the front doors, I actually had to push the back piece with a screwdriver to make it release

You will see now that there are a lot more wires (which is why I stopped trying to pop them out). And you can clearly see where the window goes down to. There is also the tweeter on the front doors, you will need a wrench to take it off (if you choose to, easier to apply that way - I ran rattletrap over it and then cut out the two holes).



I removed the plastic again, applied pieces to the outer door panel, then to the inner.



To put the doors back together:

- Reconnect any fasteners or wires you disconnected inside the door!
- Re-attach the doorhandle piece that you popped out
- Drop the door panel back on, starting with putting it on the window pane
- Make sure the wires for the door that need to be connected can be reached
- Pop in all the fasteners on the door
- Put back in the three screws (two in the black door piece area, one where the doorhandle is)
- Re-attach the wires to the black piece and pop that back in

Done with the front doors! If I’m missing anything I’ll write it in if I remember.

Door Wrap-Up

- I did a single layer of the rattletrap on both the outer and inner door panels, no double-layering.
- Dellrio did say the big goal of the doors is to give them more weight, which I did.
- You can feel especially the front doors a bit heavier to open with a more solid close (the back doors not so much. Not sure if I did anything wrong or it’s just the back doors?)
- I didn’t notice much of a difference outside the car in terms of how much sound was kept inside. Again, not sure if I did anything wrong, if I should have applied more to the outer door panel or something.
- Sound quality inside sounded a bit better in my quick test out to get some food.

Day 3

I took care of the hatchback today. This small area was actually a bit more frustrating than the doors to be honest. I did end up doing both the inner and outer panels. In case anyone is wondering the hydraulics still open the hatch up just fine. And it closes with an impressive slam now.

The first thing you need to do is take off the black felt part. There are 10 fasteners, with lots of teeth. I went through different ways to get them out - pulling the fabric down (didn’t work well, the fasteners just slipped through the hole); prying them out with a screwdriver, both above and below the felt (worked, not great); and then grabbing them with needle nose pliers and pulling them out (mostly worked).




One thing that confused me is the grooved metal piece that’s on both sides of the outer panel. I’m not sure what it is, or what function it holds. Weight for the door? Toyota’s own sound deadening? For better or worse I did not put the rattletrap over it.



I did end up unplugging the two plugs to reach in more. The right side was super easy to fit my hand in, the left is a smaller opening, plus the wire, and was a bit of a pain.



I did manage it finally, and then I covered the inner panel with rattletrap. I cut a hole to the power that does the latch button. I didn’t cut one to the license plate lights, I’m sure I will have to replace those eventually and will cut it then.

There’s also what looks like a negative connector for power? I did not cover that. Wasn’t sure what would happen if I did.



But anyway, that’s done! I took the time today to verify that all my buttons on the doors and hatch still functioned properly.

Day 4

Okay, I was able to do the roof and floor of the car in about 9 hours, including stopping for a quick lunch. And a few small breaks to get into the air conditioning out of the sweltering garage.

I started with taking the seats out. Each is held in by 4 bolts, three of which are under plastic covers that pop off. The bolt is an E10 style, and with how tight they were in I would definitely recommend having that socket on a wrench or you are going to strip them. Honestly I almost gave up a few times, those bolts were in extremely tight. Have a very powerful drill or powerful upper body strength to get them out.

Once the screws are out take off the headrest. Then lean the seat back and unplug the three cables underneath (remember to have your battery unplugged or doing this will set off airbag alarms that need to be reset by the dealer!). Then take the seats out.

Next I took out the center console. Pop the small button section out and disconnect it. Then pop the plastic piece that is along the shifter and the button area. Underneath by the shifter are two screws, take them out. Then take the screws out inside the arm rest (ones with a holder have three screws in the bottom). Then grab the cup area and pull towards you and up, it will pop out. After that pull the rest of the plastic up and it will come out in one large piece.

Then I took the trim apart, popping it off starting at the front of the car. There’s a piece blocking plugs at the front of the car on each side, then the door trim, then the B pillar trim where the seatbelts are. This one is two pieces, the bottom pops off and then the top one has two screws at the bottom, and then pops off. On the bottom one on each side the fasteners stayed attached to the car so I had to pull them out with pliers. Then I did the rear seat trim, which is two pieces.

I was going to take out the rear seats but since I wasn’t going to put any rattletrap on top of or below the battery I decided against it. This did make it harder with the rear plastic though (below).
Then I took off the battery cover to have access to the carpet in the back. The clips for the battery compartment are.. a pain. They come out easy (push the center in and they pop out). Putting them back in.. I haven’t figured it out yet (3 days later). The plastic pieces are sitting in place with the clips in a plastic bag.

Next I took the carpet out. There are two pieces, front seat and back. Both are held into the blue clips under the door trim so detach that. The front has velcro near the shifter, detach that. Then work it off. The rear seat carpet works about the same way, except it’s held in by two plugs near the battery. I tried to get the first one out with pliers and it broke. The second I tried to pull out with the carpet and the carpet ripped. I ended up cutting around it. It’s covered by the battery cover luckily. Then the carpet will come out. Then take out the insulation and styrofoam!

If you are just doing the floor you can stop here and do it. I was able to double-layer the floor. The air condition “vents” to the back seat were a bit of a pain, I was able to take out the passenger and go underneath it but not the driver, so I had to slide the rattletrap in as best as I could. I did not put any material under the battery or under where the wires run on the trim.

When you are done just reverse the above process! And be careful to not cover the plastic pieces for the front driver floormat with the carpet like I did. Not sure how to go about fixing that now. It would be such a pain to pull the carpet back, so my other options are to leave it or cut the carpet.



If you are doing the roof, keep reading!

Head to the hatchback and take everything out. Then pop off the plastic piece along the bottom edge of the trunk where the door lock is. Next take out the two black pieces, one on each side. There are two screws on the bottom and one on the side, then they pop out. This will give you access to the top panels which need to also be popped out. Note: Not removing the rear seats made it harder than it should have been to move around the back panels I think. They were stuck on the seats and I was not able to take them out and had to work around it.

Now removing the headliner is.. exciting. Starting in the front:

- Pop out the light and disconnect the wire
- Pop out the microphone if you have it and disconnect the wire
- Unscrew each visor and remove it.
- To remove the visor clip twist the plastic 45 degrees and pull it out.
- To get the other part of the plastic.. honestly I don’t remember. It was a pain though.
- Pop open the A frame covers over the headliner and cut the electrical tape attaching the wires to the headliner in there.
- For each grab bar you pop it open a bit from the bottom with a flathead screwdriver, then grab both sides and twist 45 degrees again, it will pop out. Then the grab bar will come. The metal pieces may or may not, don’t lose them!
- Remove the two fasteners in the middle of the car holding the headliner up (I used pliers, carefully)
- Remove the fastener in the rear of the car
- Pop open the rear seat belt holder, then unscrew the seatbelt part.

I think that was it.. double-check to make sure! Then I started pulling the headliner down from both sides, very gently (and even then it still bent some). There are wires attached with electrical tape above the driver’s side, and then a wire running the passenger side back to the antenna taped up. Once that’s all free and the headliner is coming you can pull it out the back of the car.

And when you are done, put it all back together! I did not put any material under the A pillar by the airbag and was sparing with it on the rear pillars near the air bags. I did line the hatchback floor with it where the tire goes.

I was most worried about the headliner and I didn’t mess it up too badly. Ended up denting it a bit putting the seats back in. Also I managed to get the front seat stuck on the arm rest so now the covering is ripped up. Not happy about that!



Conclusion

I hope this write up helped some people! I’m glad I did it because I learned more about my car. It definitely seems to help with road noise, on most surfaces. I am hearing more of my tires, engine and wind against the front windows though.

If you have questions ask and hopefully I can answer!

 

Good to know about the back doors not having the same thud as the front! And that your speakers can still be heard somewhat outside of the car. It probably is better for a subwoofer, and when I put that in if this keeps the car from rocking outside that will work fine. I'm definitely in it for the road noise reduction first and foremost.

And thanks for letting me know about the airbags. I am going to try to avoid that if it at all possible!

With the hatchback, do you know what the grooved metal is that is on both sides? For the life of me I couldn't figure it out. I ended up putting the rattletrap around it just to be on the safe side.

But my hatch is done, updated the original post!

 

I was able to get this done in about 9 hours on Saturday. Everything went pretty well, I didn't end up breaking anything. Well, one of the last things I did was put the seats back and I caught the armrest with the bottom of the seat and it tore the fabric, ack!

I also forgot to pull the carpet around the two plastic pieces that are meant to hold the driver's floormat in. Not sure what to do about that, it would be a super pain to pull back the carpet. Either I just leave it (I guess they are meant so the mats don't slip when driving?), or cut the carpet to let them out.

I did some driving the past two days, it does seem to be better with the sound. I hear much less noise from above/below the car, however I feel like I hear (or just notice more) the tires, engine and wind on the front of the car. Not really sure what can be done about that. Probably nothing.

Am I happy I did it? Yes. I think it helped. I'll know better the next time my wife and I take an hour long drive (Thursday) and see if it's easier to talk. So far it's just been me!

Pictures are up in the original post. I'll write up how I went about everything soon.

 

Not surprised. My tC had them as well but they broke after a few years and I never noticed any issue really without them so I'm not too concerned.

Original post is updated with the rest of the details! I hope this helped someone

 

I was able to get the floormat notches back out by removing the outside trim and unscrewing the driver's seat and tilting it back. I pulled the carpet up just enough to go in the right way under the notches so that's fixed, whew.

I'm still at a loss on how to put the battery clips/pins/fasteners/tabs (whatever their official name is). I feel like I just need new ones. Is there anywhere to get them besides the dealership?