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"Sound deadening is a waste of time and money; Prove me wrong!"

79K views 295 replies 77 participants last post by  huberoy123  
#1 ·
Basically what the title says. Sound deadening is pointless.

Forked from here:

http://www.diymobileaudio.com/forum/5540297-post26.html


Where I stated that:

"I went crazy with the sound deadener on my 2001 Accord. It made no measurable or audible difference. Car Stereo Review did the same with a Camaro back in the day, measured it before and after, and found that it made less than a decibel of difference.

Swapping out the tires on my 2005 Accord made a measurable and audible difference. The data is over at Tire Rack, I'm too lazy to look it up. If you want a quieter car, swap out your tires.

My Genesis is super quiet, and so was my Audi. From evaluating how the factory does it, it seems to come down to :

1) dual pane glass

2) Obsessively sealing off the cabin. Seals on every wire, big seals on the doors, and a trunk that's physically walled off from the rest of the cabin. No ski pass through, no fold down trunk, no CUVs, no SUVs.

3) Attention to detail: the fans in my Genesis are much quieter than the fans in my Mazda

My Genesis probably has about 20 lbs of sound deadening in the entire car.



If someone can prove me wrong, I'm all ears, but I've never seen any data that demonstrated that sound deadening is worth the trouble. If you want a quiet car, buy a quiet car.


 
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#4 ·
do a normal install without deadening that doesnt include sticking multiple small drivers in some contraption thats double sided tape to your dashboard and multiple 4's in a bandpass on your floor and let us know what you think.

an audi and genesis are going to be a bit different than your standard camry or civic, but there are still benefits.

as far as measurements.. here you go

http://www.diymobileaudio.com/forum/3522858-post1723.html
 
#9 ·
do a normal install without deadening that doesnt include sticking multiple small drivers in some contraption thats double sided tape to your dashboard and multiple 4's in a bandpass on your floor and let us know what you think.
Image
 
#6 ·
I won't say it's pointless but my Jetta didn't get any treatment. I really enjoyed the sound and got a lot of compliments without it.

I think it goes back to goals. There's data that shows what it can and can't do. If you're trying to lower ambient noise, you can't beat sealing off the environment. I think it's easier to reduce resonance and energy transfer though.

In my Jetta, the tweeters are chambered, mids were open baffle, while mid bass and sub were sealed.

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#7 ·
PB, are you talking about using ONLY CLD tiles (i.e. "dynamat style" panel deadening) or using a properly installed CLD/CCF/MLV layered approach to sound deadening (i.e. goal is to reduce road noise inside the listening space)??

If the former, you are likely correct.

If the latter, my experience with applying CLD/CCF/MLV only to the 4 door panels in my truck, indicates to me that you are wrong.

And I have yet to apply this process to the entire truck, including wheel well liners, where I expect to again Ann even MUCH quieter listening space inside the cab.
 
#11 ·


If someone has some measurements, I'd love to see them. I measured my Accord, a ton of work and zero difference. Car Stereo Review did the same with a Camaro, there was a marginal difference, like a fraction of a decibel, but that's basically inaudible.

Unless someone can prove me wrong, I say sound deadening is a placebo.

 
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#8 ·
It always very obviously helps my installs when used near high power lower frequency drivers ... it is night and day.

Surely how it is used will matter a lot, the benefits seem more noticeable at higher volumes, it doesn't really fix everything, and there may be cases where it doesn't do much at all (certain cars/installs/applications).

Your statement in the original thread that I responded to (not included in #1 above) sounded like an over-generalization to me, that's all.
 
#15 ·
Re: "Sound deadening is a waste of time and money; Prove me wrong!"

The reason I didn't put any work into the Jetta is #1 I'm lazy and #2 Andy W. has made similar comments... Except the part about no results. He just said juice isn't worth the squeeze so to speak.

Edit: sealing doors as best I could or using sealed boxes for mid bass and adding DSP have had the greatest impact on my hobby


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#18 ·


Sound deadening doesn't do anything about reflections.

It also doesn't make a car quieter, or at least that's my argument ;)

 
#17 ·
SkizeR makes a funny point, my projects DO look like ass. That's true.

There IS a way to make the car SEEM a lot quieter:

Something really odd about arrays and constant directivity waveguides is that they make the car sound SIGNIFICANTLY quieter.

Here's why:

Image

A conventional speaker is loudest on axis. A constant directivity waveguide, or constant beamwidth transducer, they sound the same across their beamwidth. As the name implies.

I got into them because they image well, but the first time I put one in a car, something funny happened:

I couldn't hear a damn thing outside of the music.

It was actually unnerving, it's probably not safe. These types of speakers sound like you're listening to a giant set of headphones, except you're not. But in the car, the effect is that same, you can't hear anything but the music. The road noise is drowned out, the engine noise is drowned out.

Obviously, everyone would say "if I turn up my music loud enough, I can't hear anything."

But these speakers aren't like that; even at polite levels, they drown everything out. This is just a weird side effect of their coverage; they don't cover a room the way that a regular speaker does, the coverage is very even.

Even D'Appolito speakers don't do this the same way, because they're only constant beamwidth over a narrow range and only on one axis.

A symmetrical waveguide has constant directivity over five or more octaves.

Note that underdash HLCDs don't do this for the most part, because they only control directivity on the horizontal axis, on the vertical they're basically omni. They DO have this effect to an extent, but to really get the full effect you need something like this:

Image


 
#20 ·
Here's some data to back up two claims. First, I claim that sealing off the cabin makes a huge difference. IE, if you drive a sedan you're going to be way better off than if you drive a CUV or SUV. And if you have a sedan with a fold-down seat, you might consider sealing off the trunk. Literally walling it off, and make it airtight. Sound has a helluva way of getting through the smallest gap, and you need to seal that cabin off. You can test this yourself, crack the window to your car half an inch. Does it get noisier?

Image

Four sedans, average DBA at cruising speed is 65-67

Image

Eight CUVs, significantly louder. Five db louder. That's audible.

Image

These are $80,000 cars. If BMW could make their car as quiet as an Accord using 20lbs of sound deadening, why didn't they? The answer is that they couldn't; the reason a Prius is so darn quiet is because the engine is quiet and the tires are too. The BMW is 5dB louder than a plain ol' Accord because Honda knows that soccer moms care more about a quiet car than having 400hp. The M5's big engine requires big tires, and creates road noise that they can't isolate.

 
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#21 ·
First, I claim that sealing off the cabin makes a huge difference. Literally walling it off, and make it airtight. Sound has a helluva way of getting through the smallest gap, and you need to seal that cabin off. You can test this yourself, crack the window to your car half an inch. Does it get noisier?

PB, "sealing the cabin" (albeit NOT airtight) by with minimizing ANY gaps and/or holes) in the application of CLD/CCF/MLV layering is EXACTLY what proper sound deadening with CLD/CCF/MLV is supposed to achieve, as many of us can attest to, is VERY effective in reducing cabin noise!!

I propose that the difference in your opinion form mine and others has to do with the fact that you are likely talking about your experiences using dynamat equivalent CLD deadening and NOT proper multi-material, multi-layer deadening and quieting techniques!!!
 
#22 ·
Well I have an incredibly loud 350z that I'm about to treat. This thing is riding on 19x11 rears and 19x10 fronts. KW coil overs, urethane engine, gearbox, diff mounts, and Nismo hard rubber bushes on all the control arms and linkages.

Road noise in it is very loud, so I'll be doing the cld, ccf, mlv.
No measurements but I'll have my ears and a bunch of other people who have ridden in it lots who can make the call.

I'll put my hand up and say hey, if there's no difference perceptible, then I'll rip it all back out and save on all that extra weight.
 
#26 ·
The problem with relying on your ears is echoic memory is only accurate for a few seconds. You will not be able to notice a difference with any sort of accuracy. You will almost certainly perceive a difference after doing all of the work, even if no difference exists. So, it may make a difference, but using your ears won't be even remotely useful.
 
#35 ·
So are you talking about resonance control, or sound proofing?
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EXACTLY what I am trying to determine about his statement myself!!

My guess is that he is talking about panel resonate and doesn't;t yet realize the full benefits of proper soundproofing using CLD along with CCF and MLV because he has never tried it.
 
#25 ·
To be fair, Patrick's point about the noise not being because the car is underdamped is pretty accurate. A few squares of vibration dampener may be needed for specific resonances, but they won't do a damn thing for road and tire noise which are much more a problem than panel vibrations. The wavelengths for those noises are too long, and even MLV is only going to attenuate them a bit.

I wouldn't say to skip the deadening process; sealing holes in the doors seems to make a real difference for midbass, and a few patches of vibration dampener can quiet noisy bits, but they can be used sparingly and specifically, there's no need to cover every exposed piece of metal.
 
#29 ·
OMG. This thread is a total clusterf*ck.

What exactly is it we are out to prove here, again? Is it that CLD (conventionally referred to as "sound deadening") is useless for every single instance one can come up with or any/all attempts of lowering the amount of road noise in your car while driving is futile, or is it one of the other fifteen things I've seen mentioned here?


My take:
Blocking sound while driving: CLD by itself; no big influence. CLD/CCF/MLV; huge difference. My car went from being a typical honda to sounding as quiet as a high end luxury car inside.


That's all I can add until someone can untangle this spaghetti mess of a thread and can provide a clear, concise point to what this thing is supposed to be.
 
#30 · (Edited)
Yes, it's easier to start off with a quiet(er) vehicle, but not everyone has the luxury to do so or may even want to choose so.

I drive a 2005 Tacoma Prerunner almost daily to work. I chose it because I love manual transmissions in pickup trucks, but I also like that it is a 4 banger sipping gas... still has good power for regular driving. One thing I did notice is that it was a noisy ass truck... like literally a hollow shell allowing all sorts of road noise to seep in. Notice I stated "was". A pretty heavy CLD was used sparingly. When I say sparingly I mean a door kit was strategically placed all over the gutted interior including doors. Sparingly because it isn't meant to ward off road noise. A pretty full layer of MLV & adhered neoprene was put everywhere that still allowed panels to fit like stock and from front to back and upwards on the firewall. I also placed melamine foam tiles within the doors and underneath the center console along with the other aforementioned materials. The difference? A good bit! Not luxury quiet, but definitely quieter than before. Noise from the transmission coming through the center console has definitely gone down. The doors & floor aren't emitting near as much into the cabin. It's still a truck and some noise is going to be apparent, but that's a given.

Here's the thing though. You want someone to prove to you, but in reality, just how many people are taking the time to actually record or measure the difference? Basically, I feel that you know this and can pretty much place your argument there. Cool, but at the same time, I have not seen you answer the question of what exact materials did you apply. Was it just CLD, or did you do the full recommended job before stating your case? That question has been asked several times.


By the way... I drive a quiet weekend luxury car that has a stereo and no deadening was done. The difference in vehicle build is obvious, but so are the things that are already included in the "luxury" car vs what's left out of the pickup.. thicker jute underneath the carpet, denser door panels, an actual trunk with the gas tank & solid wall sealing off the rear seat, etc. So what you're seeing here is one is by design as you say, the other done by aftermarket materials, but sealing off & padding with aftermarket are viable. You want proof but prove to us that there isn't a difference. We're not talking dead quiet because even my luxury car is not, but enough of a difference to be worth the use. If I have considerably lowered noise just from the 3 sources I mentioned earlier, then that's an improvement. No one is claiming that they can make a go-kart sound like a Cadillac. Come on, man. :rolleyes:
 
#294 ·
Yes, it's easier to start off with a quiet(er) vehicle, but not everyone has the luxury to do so or may even want to choose so.

I drive a 2005 Tacoma Prerunner almost daily to work. I chose it because I love manual transmissions in pickup trucks, but I also like that it is a 4 banger sipping gas... still has good power for regular driving. One thing I did notice is that it was a noisy ass truck... like literally a hollow shell allowing all sorts of road noise to seep in. Notice I stated "was". A pretty heavy CLD was used sparingly. When I say sparingly I mean a door kit was strategically placed all over the gutted interior including doors. Sparingly because it isn't meant to ward off road noise. A pretty full layer of MLV & adhered neoprene was put everywhere that still allowed panels to fit like stock and from front to back and upwards on the firewall. I also placed melamine foam tiles within the doors and underneath the center console along with the other aforementioned materials. The difference? A good bit! Not luxury quiet, but definitely quieter than before. Noise from the transmission coming through the center console has definitely gone down. The doors & floor aren't emitting near as much into the cabin. It's still a truck and some noise is going to be apparent, but that's a given.

Here's the thing though. You want someone to prove to you, but in reality, just how many people are taking the time to actually record or measure the difference? Basically, I feel that you know this and can pretty much place your argument there. Cool, but at the same time, I have not seen you answer the question of what exact materials did you apply. Was it just CLD, or did you do the full recommended job before stating your case? That question has been asked several times.


By the way... I drive a quiet weekend luxury car that has a stereo and no deadening was done. The difference in vehicle build is obvious, but so are the things that are already included in the "luxury" car vs what's left out of the pickup.. thicker jute underneath the carpet, denser door panels, an actual trunk with the gas tank & solid wall sealing off the rear seat, etc. So what you're seeing here is one is by design as you say, the other done by aftermarket materials, but sealing off & padding with aftermarket are viable. You want proof but prove to us that there isn't a difference. We're not talking dead quiet because even my luxury car is not, but enough of a difference to be worth the use. If I have considerably lowered noise just from the 3 sources I mentioned earlier, then that's an improvement. No one is claiming that they can make a go-kart sound like a Cadillac. Come on, man. :rolleyes:
random question for ya. Do you have any pictures of under the console of your tacoma? I have the same truck and I didn’t do anything under the console because it’s so busy under there, but I would like to do something.
 
#42 ·
Basically what the title says. Sound deadening is pointless.
Dude, I'm not sure if you were OK with taking yourself out of context or not but the way your thread title reads it seems more like a means of grabbing attention via a 'sensational' post. Since you didn't try to provide context in your subsequent post I can only conclude what you said is exactly what you meant and there are no bounds for the statement. So, I'll just point you to your own posts made about using CLD on things other than lessening the noise in your car (which would have been an argument I would have entertained). Surely you have some data to prove to yourself why you used CLD in these cases:

http://www.diymobileaudio.com/forum/5275370-post97.html
Nowadays I do a CLD sandwidth of fiberglass, the 3D printed enclosure, then mortite, and then another layer of fiberglass. So it's basically an outside surface of fiberglass, and inside structure of PLA, and a layer of mortite for damping. I use System Three T-88 epoxy.

http://www.diymobileaudio.com/forum/3419657-post502.html


Here's a video showing the CLD construction I'm using for the midbasses:

https://www.youtube.com/watch?v=bOal1ReM5yU