Question about sound deadening

I'm going to be upgrading some of my speakers soon, and based on lots of recommendations here I'm considering adding some sound deadening to the doors while I'm at it. However, before I spend the time and money on that, I'm wondering just how much ROI I'm going to get out of it, assuming I went with some 80 mil deadening material.

We just went on a road trip and I measured the db level in the truck. I was averaging about 58 or 59db. Does anyone have any info on how much of a reduction I can expect if I just do the doors (double cab)?

 

I can’t give you a number, but it will certainly be a noticeable difference if done correctly. It’s worth the cost of a box of Noico 80mil and a Saturday in the garage, that’s for sure

 

You might see near zero reduction with just damper in the doors. It really depends where the noise is coming from. Dampers only change resonant frequencies of a substrate - they aren't very good at blocking noise. So if the noise is coming from outside (wind, traffic, tires), it will have minimal effect. Barrier layers are what blocks noise (MLV, lead, etc). Generally the 2 are used together, using as close to 100% coverage as possible with the barrier layer, along with other elements.

So properly applied you may be able to reduce some vibrations in the door, but you haven't addressed the rest of the vehicle, so noise reduction might not even be noticeable.

 

I can say from first hand experience you will experience a perceptible improvement, although I can't qualify it by how much because I took no measurements beforehand. My sound deadening project is still in progress, but I have done 3 of 4 doors with Damplifier Pro. I'm going to finish the 4th door. I've just ordered more, and have a set of speaker tweakers, and a bunch of Luxury Liner Pro that will cover the doors, floor, and rear wall. The DP that's in there now has covered at least 60% (SecondSkin's minimum recommendation) of the outer skin, and I've done about the same for the inner skin as well.

Based on my work so far I will say it seems slightly quieter inside the truck while driving. It definitely seems more solid. The doors close with a much more satisfying "thud", very much like a Lexus. The biggest improvement so far is the clarity in the stock stereo. The bass (mid) SEEMS much louder. I think it's just energy that was being wasted vibrating the door is now being pushed out of the speaker now. It's like if I turned up those frequencies for the same volume level. Plus now there is much less resonance. I would imagine the noise floor has dropped a lot, and the same volume levels sound a bit louder, and much cleaner. I have the OEM+ speaker system on order now. When I tear down for the install I will finish the deadening. I'm contemplating even including some Mega Zorbe in the doors, but not sure if it's worth the cost. I can't find much info on it, other than what SecondSkin has on their site. One thing I hate about the Tacoma is when I'm outside, I can hear quite well what's being played or said inside the truck. I want to keep all the sound in the cab.

I can post results, measurements, and info if anyone is interested. I'm thinking I'll make a series of short videos using a frequency generator and demoing before and after sounds with the stock vs. OEM+. The frequency generator (app on my iPhone) is very helpful in locating resonance locations. Tried it the other night. Turns out my ceiling light can make unwanted noises around 50-60Hz. Guess I'll have to address that in addition to the doors and floor.

 

I don't have numbers but it helps. As an added bonus, it also doubles as insulation.

I did doors, floor, back wall and roof. Took a day or two.

Would do again

 

I did just the doors of my AC, both front and suicide doors. There was an improvement. My only "complaint" (if you want to call it that) is deadening the doors will just exacerbate road noise through other areas. I get less road noise from the doors but now I can hear road noise from the top door jams more prominently. This doesn't mean its a new noise, I can just hear it more now from that pinpointed area. Something to be aware of if you only do certain sections of your truck.

This doesn't mean I regret doing it. It was a huge upgrade and the doors make a nice 'thud' when closed or if you tap your fingers on them. Driving at slower speeds where wind noise isn't a big factor it was a huge improvement.

 

A bit of truth. Sound deadening needs to be a 2 level approach.

1. Stop the vibrations from resonance. This is the dense mat. Only need to cover about 50-60% of the vibrating panel.

2. Absorption. This is a bit more snakey...... The long wavelength sounds, think bass, is more difficult to absorb. This requires thicker absorption foam. The short wavelength sounds, think wind noise, is easier to absorb. This requires thinner absorption foam. Sound absorption will require covering 100% of the panel. The thickness of the material can interfere with fitment of interior beauty panels.

Primary, before the previous steps, is to eliminate any outside noise as possible. Body rattles, squeaks, tire noise, exhaust noise, weatherstrip whistles........

 

Thanks for this explanation. I hadn't heard this before, but this is pretty important information.

 

No problem. Deadening really is a lot of work. But a full treatment is worth every moment spent. I drive a 20 year old 1st gen, but the interior feels more like a luxury vehicle. It was a lot of work to get it there though, although really not that much money. I'm using damper at 25 - 50% on resonant panels, MLV on the interior side of that with neoprene on both sides of that to tame vibrations as well as provide some thermal insulation. I've also filled any cavities with closed cell foam and the back wall is 3/4" plywood across the whole wall. There's also countless slices of closed cell weatherstripping between any surfaces that are prone to rattling. Doors are also semi-sealed.

In addition to providing the benefits you'd expect of a full treatment, it takes some of the harshness out of the ride. It's almost like free cushy-ish suspension. The thermal benefits are hard to ignore too. You need the AC less in the Summer & heat less in the Winter. So even if you aren't into it for the audio benefits (which are significant), it's a big improvement.

 

I sometimes find myself wishing I had a 1st gen. I love the stocky, sturdy look of them. I was gifted my 2021 DCSB 2.7 (true story), but I sometimes think about how much less a 1st gen would have cost, even throwing in some extra to fix it up. With some work put into them they can be very nice, very capable and fun to drive trucks.

 

Also consider taking some foam (open cell) and covering the rear wall vents. A ton of road noise comes through there....

 

Thanks for the tip!! I’ll have my interior stripped in a few weeks for sound deadening amd audio install. I can address those vents at the same time.

 

I used foam from a gun case I wasn't using, the egg crate looking stuff.

 

Doesn’t this interfere with the vent? Any photos?

 

It does not. The cabin is still the same pressure. Remember, it's open cell foam, air still travels through it...

 

My experience; if you’re gonna have the door panels and speakers out, go ahead and add the deadening material. If not, you’ll continue to wonder if you should have done it (and if you’re like me you’ll end up taking everything apart to do it anyways).

It’s not that expensive, or difficult to do, and well worth the difference in my opinion.