This thread will outline, in detail and with pictures, how to properly sound deaden a truck and install a full audio system. I spent months planning and piecing together this build and the process was made a million times easier due to all the great information on this forum. It is my hope that this post can centralize a lot of the existing information and be an all-encompassing walkthrough for anyone looking to sound deaden and/or upgrade their stereo.

Special thanks to everyone who provided help and design ideas either directly or indirectly via their threads.

**Disclaimer: Everything outlined in this thread worked effectively for me but I cannot guarantee the same results. If you choose to do anything described here, you do so at your own risk.

First off, a quick break down of what I was trying to accomplish with this build and the products required. My goal was to quiet my 4runner and then install a defined, balanced sound system while retaining factory appearance and utility.

Sound deadening material cost: $250
Added weight of deadening/insulation: ~100 lbs

When it comes to sound deadening, there are two essential parts:

1. Lowering the resonant frequency of panels (doing away with vibration/rattles):

There are many products out there in terms of sound deadening mat: Dynamat, Brown Bread, RAAmat, Hushmat, Fatmat…the choices are endless. Some are thicker than others and some smell (for a few days) while others don’t. It is my opinion that any of the products provide an effective solution IF properly installed. I was going for a budget build and tested/used the following products:

• Fatmat (used exclusively for the inner and outer door shells)FatMat Sound Deadener Noise Killer
• Peel and Seal (used to seal EVA Mastic edges/trans tunnel/second row/rear quarters)Peel and Seal
• EVA Mastic sheeting (used on the truck floor and roof)McMaster-Carr - Polymeric Mastic

2. Blocking external noise (tires, drivetrain, environment):

There are many product options to use for insulation. Car manufacturers typically use jute (felt). Another popular product is closed cell foam. After doing some research, I located some jute locally at a higher end carpet store:

• 3/8” Liner backed, water resistant felt

A spray adhesive was used to apply the felt throughout the vehicle.

For the audio system, I went with the following hardware:

• Headunit: Alpine CDA-117 w/ Imprint Module PXA-H100
• Speakers: 2 sets of CDT Audio 6.5 Component speakers
• Amp: Alpine PDX-5
• Subwoofer: Elemental Designs e3.8 – 2ohmDVC 8”
• Accessories:
o Swi Jack steering wheel control adapter Installation Instructions
o Antenna ‘Y’ Adapter and size adapter (for mini jack)
o Amplifier wiring kit
o Scosche head unit adapter

Now on to the actual work!

Truck disassembly:

There are walkthroughs for some of this so I am going to just post links to the ones I used here since they are very well done:

*Helpful tip: Grab some tape and a sharpie. Either screw the bolts/screws back into the truck body after you remove the panel or tape them to the panel they belong to. Also circle ALL locations where parts snap/bolt on with a sharpie since you DO NOT want to cover those holes with sound deadening materials. Take pictures as you go. It will help you remember where things go upon reassembly.

• Dash/Head unit
• Door panels
• Rear cargo area
• Center console:
o There are two bolts in bottom of the center bin under the armrest, remove those along with two up front and two in the center (on either side of the shifter).
o Undo any lighting clips and lift out the console.

• Seats:
o Pop off feet covers and unbolt. Each seat will have at least two wiring clips underneath that you’ll have to undo.
o For the rear seats, just undo the bolts (4 for the bench section). For the 2nd row seat backs, fold them down and undo the 2 bolts (1 at each end) and then the center mount bracket (2 bolts)

• Carpet:
o Pull up all the door sill covers
o Remove front kick panels (driver left foot rest pops off to reveal a black rubber bumper –just unscrew the rubber bumper and then the kick panels pop out)



o Unscrew seat belt bolts at bottom of “B” pillars
o Pull off door seal trim on bottom half up to windows
o Lower “B” pillar trim should now pop off
o Rip out carpet (the factory jute and carpet in my truck was a disaster as the prior owner’s children must have treated the truck like a kitchen sink….but more on this later)

• Headliner panel (for moon roof equipped 4Runners):
o Remove map light (pull down hard at front of console-near windshield) – unplug two wires
o Remove second row light – undo 2 screws and a plug
o Remove cargo area light
o Remove upper cargo area panels
o Remove front visors and clips



o Remove all the ‘oh crap’ handles and clothes hanger points
o Remove the “A” pillar panels

*All wiring for the moon roof and lights is glued to the topside of the headliner. The wiring loom (green tape) runs down the driver’s side “A” pillar. It is fixed via two clips behind the dash, splits near the bottom of the dash, and terminates in two plugs that will need to be undone and strung up through the dash.
**The roof panel is now being supported by 4 grey clips (2 above where the second row used to be, and 2 near the rear cargo light) in addition to Velcro around the moon roof and the upper half of the “B” pillar panel. Removal of any more items will result in gravity removing the headliner for you. Make sure you have some braces or a helper nearby for the following steps (I found this out the hard way and had to do my best Spiderman impression to get the headliner out).

o Undo four clips in cargo area (using panel tool) and have your assistant/brace support the tail end of the headliner.
o Unscrew two bolts on “B” pillar upper trim and pop it off (let it slide to the ground – no need to remove this panel totally)
o Pull down around moon roof to undo the velcro and slide the headliner out the rear cargo door!




Your truck should now be completely gutted and resemble a panel van:

Sound deadening:

There is nothing complex about sound deadening. First, deaden the panel, second, insulate the panel. It is mind numbing, back breaking, and tedious work. I’ll provide a few pictures of the process for different areas.

*Prior to any sound deadening, make sure to clean every surface you plan to apply the mat to. I used a slightly diluted solution of water/denatured alcohol (do not use on painted plastics). Make sure you don’t cover those bolt holes and mounting locations that you circled with the sharpie. Sound deadener is a bear to peel off.

• Roof
o Out of the all the areas, this is where I was most particular about tolerances and ensuring my headliner would fit back properly. I purposely left the first section behind the moon roof void of the felt and only applied deadener. This allows more clearance so the moon roof can retract unhindered. I applied both deadener and felt to the other roof spans.

EVA Mastic in place:



Felt in place:



Moon roof (no felt installed on 1st span where glass retracts):



• Front floor/trans tunnel

Stock:



EVA Mastic in place:



Peel and seal installed:





Felt glued down:



• Second row

EVA Mastic in place:



Peel and seal installed:



Felt glued down:





• Cargo area

Stock:



EVA Mastic in place:



Peel and seal installed:







• Doors
o Deaden the outer door skin. Start at the bottom and layer the deadening working vertically up. You want to create an overlapping ‘shingle’ effect for water that will be running down the inner door and draining out the bottom. Make sure to get all the air bubbles out and DO NOT cover the bottom drains.



o Make proper access hole covers and fix them to the door (some people use metal and screws but I used ABS plastic cut to shape and caulk)



o Deaden over the inner door panel and access covers. You should now have much nicer ‘enclosures’ for you speakers.



• Interior plastic panels
o Basically, I applied some sound deadening mat on the big flat areas that would be most likely to rattle. I added felt to the back of the plastic panels with the exception of the doors (I may go back and do them at some point as well as the rear cargo door).
• Speaker adapters/subwoofer box
o I read on a car audiophile forum about guys packing non-hardening clay as their seals between speaker adapters/speakers and on the outside of the adapters and figured it may not help, but it certainly can’t hurt. It definitely added a lot of heft to the adapters. Same routine with the modified factory subwoofer enclosure. Sound deadening on the end and back side.

Audio System Installation:

• Head unit wiring adapter –after much research there appeared to be 3 options for anyone with a JBL system wanting to go to an aftermarket headunit and NOT integrate the JBL amplifier.

1. Metra TYTO-01 or JAC TATO integration (use the included wiring harness but not the integration unit)
2. Tap into the 4Runner factory harness
3. Cut apart your old JBL headunit, dremel the harness plug off the circuit board, and solder straight onto the pins. (my factory head unit was partially defective anyways and I had a helluva good time sawing into that thing!)
I obviously went with option 3. But the pin chart I provide below should help anyone doing option 2 OR 3. By tearing apart the headunit I also found $2 in change (former owner’s kid’s personal piggy bank??). Certainly could have been the reason why the tape deck was non-functional.

PIN CHART (use 'Sequoia 20 Pin')

Factory adapter!:



After a little soldering (I bent the unused pins out of the way and insulated them off with heat shrink tubing)...new wiring harness:



• Speaker adapters/wiring. The stock brackets work well, just needed to either buy or make an adapter. I made my front woofer and tweeter adapters out of HDPE (cutting boards from Walmart provide a very cheap alternative). They’re waterproof (better than mdf which will absorb moisture if untreated) and will not vibrate.



Ready for speakers:



Tweets mounted to factory brackets:



X-overs and speakers mounted:



For the rears, I used ½” plastic spacers packed with clay. By drilling through the factory wiring routing system I was able to run my aftermarket wiring neatly through the adapter without having to drill a hole in my door. Using a hole saw, I mounted the rear tweeters in front of the door handle on the rear door panels. Building in a disconnect for the tweeter wiring makes future door panel removal easier.





Rear panel - tweeter holes cut and mount in place:



Rear door speakers installed:



• Door panels. I cut the speaker trim down on the back of the panels and removed the center support brace on the front doors so I could locate my X-over in that location. I also drilled out the JBL nameplates (which were pretty beat up) and replaced them w/ the ‘CDT Audio’ tags I peeled off the X-over covers.





• Subwoofer enclosure. After several attempts to keep a portion of the factory box where the amp is located, I had to cut it completely off and seal up the factory box. It was the only way the PDX-5 would fit. I fabricated a mount out of ¼” mdf with sheet metal brackets that secure the aftermarket amp snugly in the stock location.

Original box:



Box after cutting/sealing/reverse mounting sub:



Amp mounted on mdf w/ brackets:



Everything snugly in place, OEM style, but with more power!:



• Wiring. Pretty standard. Ran power through the factory firewall seal (resealed it of course) down the driver side and over. RCA’s/remote/speaker wire down the passenger side and across. Imprint tuning module in the glove box. Speaker wire can be snaked through the factory door grommets with a pin file/silicone spray. On the rear doors be sure to secure the speaker wire to the factory loom which runs low inside the door (otherwise it may interfere with window operation).





Once everything is wired, fire it up! Hopefully you hear music haha.

If so, it’s time to double check everything and reassemble.

While researching sound deadening/insulation, there were many claims and opinions about how well it did or didn’t work. Much of it is opinion with no numbers to substantiate claims. In an effort to provide something more quantifiable, I ran a series of tests for decibel levels both pre and post installation. I used an inexpensive DB meter but I took enough readings in near-identical conditions to provide an accurate result.

Conditions for both pre and post testing:

• All windows up, moonroof closed and covered, radio off, A/C and heater off
• Reading taken at head height above center console
• 65 miles per hour on the same stretch of highway (speed limit) in same direction.
• Fair weather conditions with no wind

Pre-sound deadening results: ~90 db (averaged over several runs over several days). Consistently gave readings from the upper 80’s to lower 90’s.

Post-sound deadening results: ~85 db (average was actually around 83) Readings ranged from upper 70's to mid 80's. Now, I'll be conservative since I'm using a cheap measuring tool and say that I reduced the decibel level inside by 5. May not seem like much looking at numbers, but when you consider that each 3 db reduction results in a 50% reduction in sound intensity it's a drastic change.

In conclusion, the truck is now extremely quiet. It is much easier to have conversations in the truck at speed and you can hear all the intricacies of the new system. One result which I did not expect was that the truck itself feels more solid and all the little vibrations and rattles are gone. Total project time was about 70 hours (conservative count). I would definitely do this project again...for a truck with 95k miles, it's honestly like it's brand new again!

I took many pictures so if anyone needs pictures of certain areas of the truck, just let me know!

Final pictures:

Head unit w/ Scosche adapter:



Doors:







Cargo area (I still have yet to cut a hole in the access panel grill so the subwoofer magnet will clear):





Night shots: The blue headunit lights aren't as glaring as they appear in the pictures.

Wow! Now that is detailed. I wish I had the time to do something like that. I just installed a new head unit this weekend and finding time for that was a big deal.

What a neat project dude! Sure takes a long time and i noticed two night shots there, but i bet the results are awesome! 5 stars for you!

I'm currently wiring my whole entertainment package. I already installed a pioneer dvd headunit 3300bt and i'm still waiting for my two headrest screens to come in. Once those are in i'm hooking up an xbox 360 to the back screens. This means that we can watch a dvd on all three screens and/or play xbox in the back!

I really would like to see that post decibel reading. This seems like a nice, but time consuming project. Just figuring out how to take out all the panels will take me a whole day!

Excellent job! Great write up. Do you have a finished shot of the sub, with everything put back?

Very nice work! Regarding lowering the frequency of resonant sound, from the brief research I did, total coverage with the material onto the metal area isn't necessary. I heard coverage of only about 30% of area was needed. The next (2nd) step, when you go to DEADEN the sound, you need 100% coverage (the 3/8" liner......preferably high density material on top of your "peel and stick" material). Looks very labor intensive. Luckily I'm not an audiophile. Good luck and Thanks for sharing!

I'll be taking some photos with everything closed up this afternoon and try to get them posted this evening.

Everything fit back in place but the tolerances are extremely small now. only parts I couldn't fit back on were the plastic caps for the front seat, rear mounting points (husky mats cover this area anyways so no big deal!)

Cookieroe - good clarification on the sound deadening. I had read 70% coverage (that was for door panels which are typically the most resonant) for dampening but after doing the install I can see how 30% would certainly work in most areas. However, I tend to go overkill plus I had a ton of materials so I figured I better use them!

HokieRunner, VERY thorough and extensive. Please post some of the post build pics and DB counts. Looks Sweet!

EDIT: did you try driving with no seats! =)

Thanks! Post build pics are up and I'll have the post db levels done by the end of the week.

I didn't try driving without the seats but I'd be lying if I said it didn't cross my mind.


It definitely sounds incredible and there's still some room for fine tuning and improvement.

Very clean. Night shots look sharp.

hater.

your build looks extensive and awesome but seriously, you know dynamat suggests (and demonstrates) that you only need to cover 25% of a surface to effectively utilize the product.

Im sure your project is legit if you have 6 15's in the back and were going to audio shows like a tool, but since you dont have plastic windows im assuming you dont.

you effectively added like 1,000lbs of weight to your 4runner for no real efficient purpose. its probably more bulletproof now! congrats tupac.

waste of capital. you could have cut 1/2 the $ off the top and added a better h/u with nav.

Thanks, I think it's awesome as well. As for the rest of your comments...I hope you feel better now!

Post sound deadening DB readings are posted. Sorry for the delay but between work and less than ideal conditions for replicating pre-install testing conditions...it took a while!

Also, I included the cost and weight of the sound deadening products for anyone interested. As stated in the first post, I went with cheaper sound deadening products and therefore was able to get almost 4X the amount of dynamat or more expensive product I'd get at the same cost. So...thus the 100% coverage as opposed to the 'effective' 25-35% coverage.