Unrelated Acoustic Question

T

ThaArtist

New member
Maybe someone might want to tackle this. Would 703 or rockwool be of any help to quite down cars from highway noise? Tires on the pavement, wind, etc.

There are so many products available that are expensive and supposedly barely do the job.

Also, do you think carpet padding would work? Alot of cars I've worked on have something similar for insulation here and there.

The only problem is I've noticed on some cars they design their door frames around limiting resonating noise so that could also be a factor in deciding how to dampen/insulate the door.

Any views on that would be cool.
 
It does sound ideal, the problem is there is no real world application since its 1" or 2" thick.

I guess we are looking for something breathable fire rated if possible and super dense so it could be thin as possible?

However, it could be cut and spray glued in between the door frames and other crevices?

Hmmm but wind probably gets in there so that might create a disaster of insulation flying out of the car or into the car?
Solution is to wrap them in something before gluing in place?
 
The best way to isolate from unwanted noise is by increasing wall density, which will reflect the unwanted noise away from your recording space. (Have you noticed the thick concrete/stone noise barriers where highways run thru residential areas of cities?).The materials you are considering will keep the sounds from reflecting within the recording space and may absorb some high and high-mid frequencies, but the more powerful lower frequencies will come right through. Ideally, a decoupled room-within-a-room (an isolation room) would be the best answer if you can manage it. Short of that putting more layers of sheetrock on the walls of your recording space would help.
 
Imho rock wool would be an unsatisfactory material for use in automotive applications. The frangibility of the material does not lend itself to use in environments where there is a great deal of vibration, and the size constraints involved (Rock Wool takes a substantial amount of volume to have meaningful effect) do not lend themselves to the confined space of an automobile.
my thoughts, ymmv.
C>
 
Imho rock wool would be an unsatisfactory material for use in automotive applications. The frangibility of the material does not lend itself to use in environments where there is a great deal of vibration, and the size constraints involved (Rock Wool takes a substantial amount of volume to have meaningful effect) do not lend themselves to the confined space of an automobile.
my thoughts, ymmv.
C>
 
ThaArtist said:
Maybe someone might want to tackle this. Would 703 or rockwool be of any help to quite down cars from highway noise? Tires on the pavement, wind, etc.

There are so many products available that are expensive and supposedly barely do the job.

Also, do you think carpet padding would work? Alot of cars I've worked on have something similar for insulation here and there.

The only problem is I've noticed on some cars they design their door frames around limiting resonating noise so that could also be a factor in deciding how to dampen/insulate the door.

Any views on that would be cool.
Click to expand...

Nope - not the right products - you need thin and dense - and these products are neither....

Doors are also problematic in that they have moving parts - locks and windows - and very limited space for those components -

you would be much better suited to look at products like this:

http://www.jm-oem.com/products/autozorbcf.asp

My belief though is that even this will be problematic for door cavities and the like - how to attach them comes to mind as the biggest problem - perhaps one of the chemical adhesive products would be better suited in this case......

http://www.quietcoat.com/

Rod
 
Well the structure is a car so as a DIY'er theres not much changing the structure. So now its all about what material will be best.

Do you think carpet pad has any sound dampening to the point where it would be beneficial in automobiles?
 
ThaArtist said:
Well the structure is a car so as a DIY'er theres not much changing the structure. So now its all about what material will be best.

Do you think carpet pad has any sound dampening to the point where it would be beneficial in automobiles?
Click to expand...

Did you bother to read the posts above? at least 3 of the posts directly answer the question.....

I will ask you one instead........ have you ever seen carpet pad that has any sort of real density to it? The only pad that comes close to what auto manufacturers use is Jute Padding - which can be purchased with a density of 12 pounds per cubic foot - BUT - because it is an organic product - it is prone to rotting, mildew - mold and odor if it gets wet (which happens quite often inside automobiles)

The pads made for cars are moisture resistant - mold and mildew resistant and are actually made for cars...... why try to reinvent the wheel?
 
ThaArtist said:
... Do you think carpet pad has any sound dampening to the point where it would be beneficial in automobiles?
Click to expand...

They do use carpet pad type material in cars. I had a late 70's Cadillac Seville. That car was pretty expensive in it's day, about 3x what a Nova cost. But they were basically the same car, the Seville was designed off of the Nova. I completely dismantled one of my Sevilles and that car had unbelievable amounts of carpet padding in it. Probably, in the whole car there was the amount like maybe five 40 lb bags of dog. I still have some of the padding. And the car was super quiet.

In the 90's I made a custom car - made many of the body panels from fiberglass from scratch. I got the car street legal and drove it for several years. I bought a lot of auto carpet padding from J.C. Whitney for it.

So yes, carpet padding works, they use it all the time, and it's the #1 reason an expensive car sounds so much quieter than a cheap car.

If you watch Chip Foose's show they use a lot of Dynamat, which is basically that with tin foil on each side.

To hold carpet padding in, I use contact cement. That's what GM used. You don't need to cover the whole thing, just some in strategic places, and it usually requires 3 coats of contact cement on both sides.

The padding you'll get out of old cars has the problem that it's usually formed and cut for the exact panel it goes on.

Filling auto cavities with expanding foam helps too.

I've also used auto carpet padding on the inside of my Maytag dryer (made it way, way quieter - drastic!) and our dehumidifier - worked great.

I've dropped the headliner in a friend's cheap pickup truck and put padding in the cab ceiling and what a difference that made! The more padding you can put in a car the better. One of the biggest differences in why a luxury car is quiet is also that they usually have massive padding on the inside of the hood, and cheap cars often have none. :mad:

There's even some people I'd like to use it on! :)
 
LOL--I misread your original post and interpreted it as blocking noise from cars getting into your studio. d'oh!! sorry for being an idiot!
 
I'm surprised no-one, not even Rod Gervais, has said this, but sound isolation involves mass and AIR PROOFING. You might want to look into better seals around your doors and windows.

I doubt you'll really be able to do much about tyre rumble, but even with this there may again be issues of air-borne sound transmission. For structural sound transmission you might want to look at your suspension, adding mass, etc.
 
dintymoore said:
They do use carpet pad type material in cars.
Click to expand...

I've also pulled some out of cars but it wasn't the commonly available household carpet padding.

Thats what I'm curious about because it's cheap. Are we talking about the same thing?

Something like these:

http://www.homedepot.com/webapp/wcs...arpet_Pads&langId=-1&storeId=10051&catalogId=

Also do you or anyone else think this would be better?

http://www.amazon.com/Elemental-Designs-eDead-Sound-Deadening/dp/B0007P4IPG/ref=pd_sim_dbs_e_1

* New Rubber Butyl Core - No Asphalt, No Melting Worries.
* Easy Press On Installation - Great results are easy!
* High Temperature Glue Design - Canada or California the glue does not break down
* 80 Mil Thickness - Hybrid Backing for Protection - Self Adhesive
* Twice the thickness standard mat products & eDead 45



That seems like a cheaper alternative to Dynamat?
 
Rod Gervais said:
Did you bother to read the posts above?
Click to expand...

Yes I did! Thanks for your input too!

have you ever seen carpet pad that has any sort of real density to it?
Click to expand...

I thought they felt heavy for a thin looking material?

The only pad that comes close to what auto manufacturers use is Jute Padding - which can be purchased with a density of 12 pounds per cubic foot -
Click to expand...

Thanks! Jute Padding.


why try to reinvent the wheel?
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I don't want to. I was just kinda wondering with my initial question. I just want to dampen my car some and not break the bank so was searching for alternatives to Dynamat.
 
pandamonk said:
I'm surprised no-one, not even Rod Gervais, has said this, but sound isolation involves mass and AIR PROOFING. You might want to look into better seals around your doors and windows.

I doubt you'll really be able to do much about tyre rumble, but even with this there may again be issues of air-borne sound transmission. For structural sound transmission you might want to look at your suspension, adding mass, etc.
Click to expand...

Yeah I'm looking at other forms of suspension too just because I'll probably start tuning this car more this summer too.
 
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