Good evening mates, I'd like to ask what would be the best way, while talking about sound insulation...

...

An aftermarket head unit might help if you're looking for louder or better EQ or something.

But I agree there's nothing like having a quieter car in the first place. In fact sometimes I wear ear plugs to block wind and road noise and then turn the volume up to compensate. Not a perfect solution, but worth it for a long drive.

So the principle of operation for dynamat isn't that it prevents the sound waves from penetrating it, it just dampens whatever it sits on to prevent it resonating? or does it do both?

It does both. Adding substantial mass to a sheet of metal will also cause it to reflect a sound wave. Sound from the outside will tend to bounce back out. Sound from the inside will as well (sometimes acoustically undesirable but typically no big deal in a typical application).

But usually if you stick to using it where it takes out ringing metal sounds, you wind up getting most of the blocking you'll get trying to sperg out with it. I don't think most people are autistic enough about audio treatments to do much good trying to sperg way out, but of course if you really want to you can layer it on and be more careful and maybe get enough additional blocking to notice and be happy about yourself with.

I guess I should further clarify why I said what I said about targeting the spots where it sounds more like a tin can.

First, of course if you put the matting there then you get both the blocking and the anti-tin-can benefit, so less matting makes more difference. (And if you miss the tin can spots, then it still sounds like a tin can despite your efforts.)

However, it conveniently turns out that the spots that sound like a tin can also turn out to be those large expanses of thin metal that do a poor job blocking outside sound. The spots that don't sound like a tin can are, unsurprisingly, where the welds and bends come together and you have thicker layers of metal and so forth for structural integrity - these of course will block more outside sound to begin with (and probably not be on the "outside" anyway where you would benefit from more blocking.)

So it's just kind of an easy rule-of-thumb suggestion meant to try to get the most bang for the buck.

Killed a lot of road noise just doing my front doors.

No doubt. Wish I'd done less on mine, but after I finally got everything back together I got in and closed the door. Didn't even turn the car on and immediately thought
>holy crap
>it's quiet in here!
Just from ambient noises of like birds and cars going by down the road and whatever.

Definitely a place where it counts. And of course on the road it's even going to help block the road noise from cars next to you.

Not going to bother reading the replies but the facts are thus;
You must dampen the vibrational energy on anything that permits vibration. You must then decouple that part with yet another layer, with another on top. Simply slathering the body from floor to ceiling with dynamat is the laziest and crudest way to accomplish sound deadening.

Almost every single person stops at simply laying on a high mass material with an aluminium backing for god knows what reason, and never bothers to decouple. The decoupling is the end goal.

This man speaks absolute truth. You can get a lot (maybe enough?) out of slapping a some matting where it counts, but too much more than that and it becomes a game of technique.

One might even consider adding absorbent material in other places as another easy thing before getting fancy. Garbage bags stuffed with household fiberglass batting crammed between the plastic liner around the back of my wagon and the strut towers and body made a surprising difference. Had I filled that space instead with 3 layers of matting on every accessible surface, it might have been even worse than the decoupling offered by empty space alone.

this is what I was thingk of doing, will try to put at least these two layers, first with the dynamat type material and then with soundproof felt.

Wish me luck lads. And thank you for all the answers. Will keep looking into this thread though.

Cars are pretty tight these days, but sometimes you can find places to fit more than felt that might make a difference. One of the typical materials for sound treatment in buildings is called rigid fiberglass or rock wool. It comes in varying densities and thicknesses. You can think of it as not unlike a really flimsy piece of plywood that gives you horrible fiberglass splinters.

You might have a patch of something like this attached to the underside of your hood to stop engine noise. Your roof liner is probably made of a really thin, stiff, molded piece of something like this. wat do?

Remember that wheel well? Can you fit a sheet of this stuff under the bottom of your trunk? Can you fit 1/2" I got 2" into my wagon without it being all weird. Now you have something that absorbs the road noise coming up through the bottom of the car. And it absorbs noise coming from within the car. And best of all, it will help deaden frequencies at wave lengths shorter than 1/8 to 1/4 of the distance between this layer and the bottom of the wheel well, and generally help stop standing waves from developing in boxy-shaped trunks and backs of wagons. Neat-o. A smaller version of like you might have noticed there's just plain less trunk/wagon noise with the back seats up rather than down.

Pics or it didn't happen

A comment on layering:

It's a long story but I had to tear the padding out of the carpeting in my foot wells. I thought this would be a good opportunity to try layering instead of carpeting. I chose a closed cell foam that worked well for dampening in other applications at low thickness without deforming over time. Closed cell means it's water proof so it won't become a soggy pile of fungus and mold. I think I did 3 or 4 layers in total and then covered it just in the outer fuzz of the rug, effectively replacing the padding.

In retrospect I would have kept the padding and only done maybe one alternating layer. The reason is subtle and requires some understanding of impedance and wave propagation. The padding was a broad band absorber affecting with some significance sound waves for which 1/4 to 1/8 of the wave had to travel through the padding before reflecting off the metal/matting on the floor pan.

With nothing but fuzz, those waves reflected very easily off the alternating layers. Now the main effect was on wave lengths long enough to go through the layering and bounce back up off the road. So it did more to help with lower frequencies coming from within the car or from under the car, but the sound from the stereo or people talking sounded more like being in a metal drum coated with rug fuzz.

I should add: we also have to think about road noise transmitted through the body of the car itself. The rug padding relatively low density (low impedance) compared to the metal of the body. So the rug does not conduct these vibrations into the cabin very well (the larger the impedance change, the more a wave reflects).

But the layered matting is more dense and better coupled to the body, so it more easily radiates vibrations of the body itself into the cabin.

read this guy's website
sounddeadenershowdown.com/
his methods work extremely well
i did it for the doors on a 3rd gen.

i made a video on my car, it covers the basics
youtube.com/watch?v=ifE2F-FTBxY

The real question is why would anyone love a chevy?
Especially a 40 year old chevy.

>Especially a 40 year old chevy.
it's 25yrs old
excellent platform to start from
good handling with a few mods (raising/lowering roll centers ex.)

i sound proof'd my 08 Legacy with Roadkill sound deadening (floor, doors, trunk). while it helped improve the sound tremendously, it didnt do much in terms of reducing noise. road noise still coming through the wheel wells, and this is the most common area for road noise other than firewall.

If i were to do this again, I would lightly apply dynamat-like materials to reduce resonance, then cover the area with Mass Loaded Vinyl. it's a lot cheaper and more effective to reduce road noise than apply sound deadener materials.

thank you. Will read and watch for sure.

seeying how I love my twingo and love its form I can say I understand the guy.

Also, if I could get my hands on a sporka I'd do the same, these things jusre aren't build in today's cars.

Whoever drove a ford ka knows how well that thing handles.

>But the layered matting is more dense and better coupled to the body, so it more easily radiates vibrations of the body itself into the cabin.

so.. one should not overdo it with more layers, just the
Acoustic Thermo Butyl/Rubber Blanket and another layer of 5mm to 7mm of acoustic felt, more than this might compress the materials and transmit the vibrations from the outside to the inside? (talking about the car floor)

A Renault isn't a Chebby tho.
Take a walk down the cevy death row in a junkyard some day.
If it doesn't build an extreme hatred for the shit box company I don't know what will.

Anyone have any suggestions for heat insulation on the ceiling? With t-tops and poor HVAC I want the cards stacked as far in my favor as I can.

You're thinking in the right direction. This stuff is as much art as it is science, which is why audio people are so autistic and argue all the time about who had the best autism.

In my car I have thick rubber floor mats for all the mud, snow, rain, ice, cum, cigarettes, half of the toppings I ordered for my hamburger, and the can of /sips/ that flew out of the drink holder when I was getting hektic. So this thick floor mat acts kind of the same way another layer of dynamat would on top of the rug padding or felt or whatever - another decoupled layer.

Same as for a house. There's already probably a gap of air between the roof itself and the roof liner, which is like having a gap of air between the outside of your house and the inside wall, or the gap of air inside two-layer glass.

Air is a pretty good thermal insulator, but if you put fiberglass batt in there instead, even better. Or a lot of times people will do things like get a can of great stuff and spray it on in to save the trouble (don't do this to your car without posting pics so we can laugh at you but the point is you can stroll around the hardware store and use your creativity)

sounddeadenershowdown.com
There really is no other method that comes close. You will be disappointed with dynamat, it keeps panels from vibrating but doesn't actually block out road noise.

this site has a more practical view on the matter, from a guy that sound deadened 2 of his personal cars and then posted pictures and results of his work:

dynamat.eduardomaio.net

What is a cheaper way to do this? fuck paying 5$ for small pieces of rubber

Lurk a form for people advertising cheaper alternatives. You can get lots of these kinds of things cheap out of an industrial supply catalog if you buy in bulk or if you happen to live near a wearhouse you can just go drive to.

When I was playing with mastic I got it from a neat helpful guy named rick. RAM audio I think. That was a long time ago. When I wanted to play with rock wool I found out there was distributor in an industrial park 20 minutes away and the chain smoking guy who works the front office loves to chat about all the recording studios and theaters and stuff and what they use and do.

And let me emphasize what many in this thread have said. If you really want to do more than something quick and easy, it counts to find people who know what they're doing.

When I was playing with closed cell foam (which I use for other things as well, as simple as making an external hard drive not vibrate the desk) I had ordered half a dozen samples of different things with varying results, but rick tipped me off to a different product that beat them all because he'd been around the block more than I had.

Huh, never really thought about comparing with a rotary. Actually I never really thought to much about valve design on rotaries for that matter. Interesting.

Don't have any links handy, but there are some fascinating magazine type articles out on the net from old engine builder guys who go chapter and verse about how they think an engine should be designed down exactly every last valve angle so you can get this shape in the piston and the timing can be just so that you get the right scavenging momentum and now your port can go like this because you're going to loose exhaust gas heat by this point, on and on. Fascinating stuff.

After I cover the floor and doorr wi that acoustic thermo butyl/rubber blanket or dynamat type material, what do you lads think about felt? I know there are more noble materials out there, but these other materials i heard about, heavy rubber/eva/etc, are quite better than simple felt like pic related?

Or pic related is good enough as it is?

Thanks for all the answers so far.

That looks a lot like the kind of recycled extra fabric junk they use for carpet pads. Carpet pads are inexpensive but they work. So that's probably about the same. At that thickness it's probably hard to do too much better. That's the kind of thing where if you have a cheap loud car where they tried to save $.03 by doing nothing at all, then doing anything might make a real difference.

Materials designed for acoustic use will come with spec sheets showing listing their typical, tested acoustic properties with tables and charts and graphs depending on how seriously they want to market it for acoustic use.

has anyone figure out an effective way to reduce noise coming from the front tires? im thinking about applying some ruberized paint to the inner fender area and on the wheel well rubber liner.

Usually you can make more difference with choice of tire, possibly wheel (unsprung weight) and suspension design (especially bushings) more than anything else so that less noise is conducted into the car in the first place. But let's be honest: sometimes hooning or cost or whatever else takes priority.

So for instance after I put polyurethane bushings on my front control arms, I had so much road noise. I hated it. But man that was it. That made the difference between econobox was now racebox. Hard to compromise on that.

In the long run, after trying to quiet down everything else, the noise from the front control arms was still annoying but it was livable. But I definitely would have eventually put something on the inner fender liners eventually if it still bothered me enough. Rubberized paint doesn't have enough mass imo. You'd want something more like a layer of roofing tar (use the oil-based kind rather than plastic/rubber kind as it holds up way better over time and in spite of the weather)