DIY sound deadening?

We bought a used 1st Sequioa and it's a little noisy for my taste. I'm looking to add some sound deadening material to the doors at least, and maybe rear cargo area. 
 

Long ago, this stuff was used as cheap sound deadening: 

but what's the cheap way to cover A LOT of space with sound deadening. Cause let's be honest this Sequioa is HUGE!

Be cautious. The heat in a vehicle is much higher than building applications and the product may smell or turn liquid and run. I've seen it happen even with products made specifically for automotive.

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NOT A TA said:

Be cautious. The heat in a vehicle is much higher than building applications and the product may smell or turn liquid and run. I've seen it happen even with products made specifically for automotive.

yeah IDK what that is, but I want to avoid that. 
 

I have a tape like the one I posted under the rear parcel shelf of the 911 and it's held up well with years and heat. But the Sequioa has a lot more ground to cover.

Read dusterbd13's post in this thread: https://grassrootsmotorsports.com/forum/grm/dynamat-and-other-ways-to-quiet-a-noisy-car/128976/page1/

Dynamat and other butyl rubber (or toxic ashphalt, in the case of the hardware store stuff) products backed with foil are only made to dampen panel vibrations, they are not "sound deadener" per se, that is what stuff like mass loaded vinyl is for. If panel vibration isn't the source of the noise it's just dead weight.

I used acoustimac mass loaded vinyl from www.acoustimac.com,  yoga mats from walmart and fatmat from amazon.com.

They worked well for my old 4runner.

Yeh, as noted, you don't need to coat the inside of the car with heavy rubber to kill a lot of the sound.  It will work, but it will be super heavy.  Just putting a small square in the middle of any flat panels will do 90% of the work.  For more deadening you can use lighter weight stuff (like jute mat).  Probably not an issue on that vehicle, but make sure there ar NO air leaks (e.g. holes). Even a tiny one can transmit a huge amount of noise.

First you need to identify what you're trying to deaden.  Attenuating high frequencies is totally different from low frequencies.

Products like dynamat and butyl tape work because they add viscous mass to the panel and change its resonant frequency.  This works best for lower frequencies where the energy in the soundwaves is moving the panel, but it does little or nothing for highs.

Ever notice when a car with big subwoofers drives by your house, you only hear the bass?  You know that inside the car, the treble is just as loud as the bass, but all you hear is the boom.  This is because of how sound energy works.  High frequencies carry the same energy, but the pressure waves are incredibly close together.  They emit from the tweeters and hit the inside of the car and become reflected by hard surfaces or diffused by soft surfaces.  Low frequencies attack the panel and either shoot straight through, or they physically move the panel which transfers the energy to the outside.  Then the low frequencies hit your house which vibrate the siding, sheathing, and drywall.  Most of what you're hearing is your own house becoming a sympathetic diaphragm.  This is also why you carefully select a place for your mid/high frequency drivers for your home theater, but stuff a subwoofer in the corner.  Highs and mids reflect.  Bass fills the room regardless of where it comes from.

The secret to stopping the most sound is state change.  Soundwaves HATE changing phases.  A mixture of absorptive/reflective materials is the key.  That is to say, rigid and non-rigid.  butyl tape does one job; prevents the panel from moving.  If you backed that up with a layer of foam or fibrous padding, you would add another change to the path of the soundwaves.  Every time they change states, they lose energy.

When a high frequency wave energy hits something like carpet padding, the sound waves get tangled up in the fibers.  The energy moves the fibers and converts the kinetic energy into heat energy.  Bingo, no more sound.  So, when you're trying to prevent road noise from entering the vehicle, you have to identify what frequencies you're trying to squelch.  If it's tire and wind noise, focus on diffusion like carpet padding.  If it's suspension noise from bumps, focus on panel stiffness and weight.

I have done many stereo installations where a crapload of dynamat was used.  Sometimes 2-3 layers.  It really doesn't help much at all, but it sure adds weight.

Don't do this

Small patches of the butyl stuff like dynamat. Then the jute mats then  plush carpet.

From below, the sheet metal heat shields do more than isolate heat energy, the also bounce back sound, so stopping noise at the source is always a good idea.

Rear wheel tubs are a high-value target when it comes to road noise elimination. Make sure there is more than a thin carpet or vinyl over the whee tubs.  If RWD, a bit extra right over the diff helps.

In the case of the Molvo extending the exhaust tips past the rear bumper made a huge difference in interior noise levels. The big box interior was unbearable until I did that because the tublehome rear panel  acted like a speaker cone.

Heck of an expensive way to do it, but Jensen used closed cell neoprene (aka wet suit material) on their cabin floors and it works very well as both heat and sound insulation.

NOHOME said:

Don't do this

Small patches of the butyl stuff like dynamat. Then the jute mats then  plush carpet.

From below, the sheet metal heat shields do more than isolate heat energy, the also bounce back sound, so stopping noise at the source is always a good idea.

Rear wheel tubs are a high-value target when it comes to road noise elimination. Make sure there is more than a thin carpet or vinyl over the whee tubs.  If RWD, a bit extra right over the diff helps.

In the case of the Molvo extending the exhaust tips past the rear bumper made a huge difference in interior noise levels. The big box interior was unbearable until I did that because the tublehome rear panel  acted like a speaker cone.

 

I've told people for years not to do that, they do it anyway...................Case in point, my pic above & below of a customers car. That's the trunk area and the top of the gas tank. Note the customer blanketed the area and throughout the interior. I'd worked on the car one week and over the weekend they installed the butyl mat Sat and Sun it got really warm in the garage. I was greeted by the mess Mon.

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wspohn said:

Heck of an expensive way to do it, but Jensen used closed cell neoprene (aka wet suit material) on their cabin floors and it works very well as both heat and sound insulation.

I can do better than that.  A shop I used to frequent near San Francisco had a customer who soundproofed their car with extra material they got from work. He worked at Mare Island... which serviced nuclear submarines.  I suspect the soundproofing was way more expensive than the car!

Over the top sound deadening on a later model Silverado. 

https://irate4x4.com/chit-chat/95940-audio-build-log-the-gnome-s-2017-silverado

I'm keen to try Lizard Skin in the LeMans (or a suitable, less-expensive alternative)

NOHOME said:

Don't do this

 

Truth.  If you really want a fun time, wait until you get a good fender bender on that car, then install a hidden camera when you take it to a body shop to record the body repair person's string of obscenities when they find it and realize they have to add 10 hours of very messy labor to the bill.

Curtis73 (Forum Supporter) said:

I'm keen to try Lizard Skin in the LeMans (or a suitable, less-expensive alternative)

I used Al's Liner HNR on the tub of my Jeep.  It's a similar, ceramic micro sphere, latex paint product for heat and noise reduction (HNR).  Complete and total waste of time and money.

I've also dove deep on researching this. Apparently the ticket is 25% coverage with those stick on butyl tiles on each panel, followed by a decoupler like open cell foam, followed by MLV carefully taped and overlapped for complete coverage. The problem is no car I've owned I care enough about to strip the interior and do that much work. Especially since that god dam MLV is like $400 a roll and weighs a hundred pounds a roll. I'd also be gutted to spend a weekend and a thousand dollars to find it makes little difference. If it weren't for concerns about rust I'd be tempted to try and roll out 1/4" of clay across the whole floorpan of my car. I'm sure that would make things very quiet. 

Right now I'm using a pair of cheap active noise cancelling earbuds. They're good for blocking out a few db. On a similar note, I've never driven any car that can effectively dampen out the low frequency WHUMP and pressure change in my ears when hitting rail road tracks or large expansion gaps. Show me that car and I'll probably buy it. I think that frequency is around 30-40hz so extremely difficult for manufacturers to tune out. And no, it's not a lexus LS. 

Would Jute be a good replacement for open cell foams? 

Purportedly, Frost King Duct Insulation is great too, but it might be a case of "Monkey see, Monkey do" like i've done with my adventures in sound deadening.

In reply to twowheeled :

Mass Loaded Vinyl

Had to look that one up. And yeah it IS spendy.

GIRTHQUAKE said:

Would Jute be a good replacement for open cell foams? 

Purportedly, Frost King Duct Insulation is great too, but it might be a case of "Monkey see, Monkey do" like i've done with my adventures in sound deadening.

I've been using the duct insulation on parts of my van for ease of application. No idea if it is effective yet but it is very easy to work with.

twowheeled said:

Especially since that god dam MLV is like $400 a roll and weighs a hundred pounds a roll.

Homer's has 45sqft rolls for $125.

Not sure how that compares to what you were seeing for $400/roll, but it might be an ok option?

In reply to Curtis73 (Forum Supporter) :

Did You learn something today? Why yes, yes I did! 

Thanks for posting that curtis

Has anyone tried shag carpeting installed upside down?

Trying to kill high frequency noises so that I can stay sane.  Rearend gears are LOUD.

Exhaust noise is one thing, but gear whine is what really knocks your sanity levels down.

problem with carpet is if it ever gets wet you have a nasty mildewy mess on your hands. I think if you had a limited budget and relatively flat floor panels, old conveyor belt material might be the cheapest option. 

If there's one thing I can't stand, it's froths retaining vibrations in the lodge. Why can't they just go out on the deck?

Because canoes don't have decks?