Soundproofing a MKIV - How much of a difference?

Judson

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Joined
Jan 18, 2001
Location
Cheyenne, WY
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2001 Jetta
Folks -

I'm paying a local shop (Stitch Headz here in Cheyenne) to install the soundproofing materials I bought from sounddeaningshowdown.com about two years ago.

Since there's been a lot of talk back and forth in various threads about this, and interest from other members in going down this path, I figured a new thread would be appropriate.

To my knowledge, no one around here has measured decibels before and after. Oddly, general google searches on the 'net has come up with little hard information about just how much soundproofing can help.

Right now at 80 mph on I-25 going south from Cheyenne on somewhat quiet pavement in my MKIV Jetta, decibels are at 80. With the radio on loud enough to hear it, decibels are 83. (It is impossible at this level to use a hands-free phone setup. It is way way too loud.)

A modern Toyota Corolla is a 72 decibels. This is using the very unscientific measure of a decibel meter on my iphone. :)

So, the question is, why am I going down this road? After all, it's a diesel, not a Lexus hybrid, right?

Well, it's this or sell my car down the road and buy something quieter. And quiet costs money, especially if I want a diesel. Take a used A3 diesel if one can find one, or a Mercedes, or a Touareg, or a newer A6 diesel, and etc. A 2013 diesel of one of these is going to start in the mid $30ks. Mid 40s is more like it. I'm not really interested in spending this kind of money.

So, I'm spending about $2.5k on doing the soundproofing (and having a stereo upgrade while I'm at it). If I can get the decibels down to something reasonable - say 72 - then I'll keep my MKIV long term, which will save me a nice chunk of cash, and make driving my car much more pleasurable as well. If not, then in a couple of years I'm looking at selling her and getting something quieter.

Savannah should be out of the shop by the end of the week.

Jud.

PS I'll list the specs of the stereo install at the end of the week as well.

PPS Some caveats: yes I know there are other things I can do to quiet the car - lower gearing, hood liner, different wheels and tires, etc. If I can get the decibels down now, then all of these things will be done over time to further quiet down the car.
 
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dmoonen

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All cars are situated around the 70dbish range my bet is most of the noise you have is road noise and vibration from your modifications mainly suspension-bushings-tires. So essentially you made your car more louder and are now trying to make it more quite. If you have the money go for it the cars 13 years old and is paid off and if it makes you keep it longer I say its a better investment then throwing 20-30k+interest down into another car. Just my two cents
 

john.jackson9213

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Miramar, Ca. (Think Top Gun)
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Glad to see this thread!
I have wondered about using my cell phone (Galaxy S4) as a sound meter. What app are you using and on what phone? I would love to take some sound measurements in my Passat.

I can tell you a longer 5th gear or the 6 speed conversion will make a very large difference in the engine noise. Now wind noise and road noise are what I hear at freeway speeds. I would also like to have some valid before and after measurements.

Look forward to seeing the measured results from your changes. BTW, what did you get from Sounddeadening Showdown and how much did it cost?

Thanks,
 

Judson

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Location
Cheyenne, WY
TDI
2001 Jetta
I am using an app called simply "Decibels." Been using it for quite a while. I use it holding it in front of my in the driver's seat, which is all I care about.

Down the road if I keep the car I'll be putting in a 6-speed. I know that will help. Also, I will look into quieter tires, and under-hood insulation. Nothing I can do about the better suspension bushings in the rear, or the H&R springs upper strut bushings - I'm not about to change those out as I really love them.

I have everything from http://www.sounddeadenershowdown.com/products except the butyl rope. I think it cost me around $800, but can't remember exactly. Got a lot more than needed for my TDI though.

PS He updated his website with cost estimates for different vehicles. For MKIVs, here it is:
http://www.sounddeadenershowdown.com/vehicles/volkswagen-jetta-sedan-1999-2005
 
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NHgranite

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Dec 8, 2010
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New Hampshire
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2012 Passat CKRA
I'll measure my car this afternoon.

I've done full door & floor treatment w/ CLD & MLV. Transmission has a 3.16R&P, Exhaust is 2.5" full w/ aeroturbine muffler.

ATMO, it sounds great for an active 2-way + sub.


Decibel report to follow shortly...
 

Judson

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Jan 18, 2001
Location
Cheyenne, WY
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2001 Jetta
I personally only run Michelins, but they are on 17s now. I could go back to 16s, but generally, I don't think my car will get a lot quieter because of the tires.

I can say this: pavement type can make a HUGE difference on noise!
 

tongsli

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Baltimore, MD
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2000 Jetta TDI, 2004, Jetta Wagon TDI PD
Judson,

The Iphone app is not very accurate. We have a decibel meter at work from Radio Shack and it's much more accurate.

It is also very directional how your levels are measured.

That being said, Have you considered putting the sound insulation material behind the plastic wheel wells?
 

john.jackson9213

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Location
Miramar, Ca. (Think Top Gun)
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1996 B4V
Judson,

The Iphone app is not very accurate. We have a decibel meter at work from Radio Shack and it's much more accurate.

It is also very directional how your levels are measured.

That being said, Have you considered putting the sound insulation material behind the plastic wheel wells?
Two things come to mind:

1) How repeatable is the smart phone app as a sound meter? If it does a good job of repeating the same measurement result, then doesn't that tell me if there has been a measurable improvement or not??

2) How much $$ and which Radio Shack part number?
 

tongsli

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Location
Baltimore, MD
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2000 Jetta TDI, 2004, Jetta Wagon TDI PD
http://www.ebay.com/itm/RadioShack-...703?pt=LH_DefaultDomain_0&hash=item35dd3808d7

This is the one we have 33-2055. The microphone on the radio shack unit vs the iphone microphone are NO comparison. I've used both side by side and the iphone is less sensitive. The Radio shack unit can distinguish between hi and low frequencies. It also lets you control your sample rate between fast and slow.

You can switch DB ranges using the dial and it will give you max and min values.
 
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Judson

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Cheyenne, WY
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2001 Jetta
Hey Lito - long time no talk to!

The iPhone app is not accurate but it is consistent. That and my own experience is all I need. Sound is such a dynamic thing and we feel as much as we hear, which no decibel meter can measure. Just ask any recording engineer how hard it is to record something that sounds good in more than one environment!

As my car is already in the shop it is too late to use any other measurement so I will do my best to describe the difference.

I expect that I will just notice how loud the wind and road noise is! But the real question for me to be answered is: is it livable long term?

Thanks for the advice on the wheel wells. I will have to buy something specific to that application as well as the hood stuff. But that is for another year !
 

NHgranite

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Location
New Hampshire
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2012 Passat CKRA
It's true regarding poor mic performance on the iPhone. Prior to my test for Judson, I downloaded two different SPL apps.

The first one gave me an average of 68dB and the second was 77dB. Cruising at 70mph in 5th at 2200rpm.

Overall, I would say the sound dampening is an improvement. I'm happy with the results. YMMV.
 

tongsli

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Baltimore, MD
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2000 Jetta TDI, 2004, Jetta Wagon TDI PD
Hey Lito - long time no talk to!

The iPhone app is not accurate but it is consistent. That and my own experience is all I need. Sound is such a dynamic thing and we feel as much as we hear, which no decibel meter can measure. Just ask any recording engineer how hard it is to record something that sounds good in more than one environment!

As my car is already in the shop it is too late to use any other measurement so I will do my best to describe the difference.

I expect that I will just notice how loud the wind and road noise is! But the real question for me to be answered is: is it livable long term?

Thanks for the advice on the wheel wells. I will have to buy something specific to that application as well as the hood stuff. But that is for another year !

I'm positive you will be happy with everything. Would love to take a ride at a future GTG.

My buddy is going to do the same/similar with dynamat and I think he's going to line the wheel well plastic.

I have replaced my hood insulation with Dynamat and I have it on my engine cover(underside) and on my steel skid plate. But that's it for now.

L
 

dremd

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South Louisiana
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06 sprinter. 03 jetta wagon premium with 6 speed ALH swap, 14 JSW
Tires make a HUGE HUGE difference, I saw 15 db (iPhone) reduction going from Re050's (run flats) that were heavily feathered to a set of tires that were reviewed as quite.

That said, the 2014 is unbelievably quiet at 75, where as the 03 is probably similar to the 13 Camry I had as a rental last year.
 

FlyTDI Guy

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PNW
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'01 Jetta GLS
I've always thought my A4's were loud. Not engine but road noise loud. Even my new, off-the-lot Golf. Interested in the outcome of this thread. Road noise is always a high priority when buying new tires. Michelins are usually quieter than most, IMO.
 

macoombi

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Location
Ottawa, Ontario, Canada
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'02 Jetta TDI
I have that Radio Shack SPL meter lying around somewhere. I used to be into car stereos back in the day. Back in University, I sprayed the insides of my door panels with rubberized rocker coating and it made a noticeable difference in road noise just from that. Just adding some mass to the panels is going to make a difference. I'd spray everything possible like the wheel wells, inner door panels and the floor.

And tires makes a big difference. I run some half-worn out Dunlop Star Specs (sticky auto-x rubber) for my summers and they're loud as hell. It sounds like I have bad wheel bearing (I've replaced all of them in the last year) and my winter (iPikes) tires are much quieter.

But even with my loud tires, it's still night and day difference between my Jetta and my '00 Honda Civic hatchback that I sold when I got my VW. That thing was loud and it was stock.
 

str8t six

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louisiana
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2001 GLS TDI
what about replacing some of the door seals? im sure after over 10 years they are pretty worn out and not making a good seal.
 

mbalmr

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In the wild
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It may not be so much the DBl readings that are troubling, it might be a natural harmonic resonance you find annoying. Particular frequencies that disturb one person will not be noticed by another. Once you reach the harmonic of any object the sound pressure becomes amplified. This phenomon is how opera singers can shatter a glass, its also the reason your keys may jingle a bit at a certain rpm. If you could find the frequency, then you could better isolate and eliminate the sound. Some products act as buffers and others claim more. Lower frequencies pass though objects where higher ones are attenuated. A resonater added to your exhaust may make all the difference in the world.
 

dremd

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South Louisiana
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06 sprinter. 03 jetta wagon premium with 6 speed ALH swap, 14 JSW
I went on a noise hunt on my last TDI.
I put about 100 lbs of MLV + 30 lbs of CLD definaley helped, but wasn't shockingly great, to be honest it just made me notice how many rattles the car had (which I eventually fixed).
A few sheets of sticky back felt, some spray silicone, plenty of cleaning with vinylX and gummi pflege http://www.amazon.com/einszett-9148...=1416449062&sr=8-1-spell&keywords=Gummi+pfege was what was most satisfying for sure.

Current MKIV has stock suspension, "quiet" tires, full factory exhaust, new DMF, and new motor mounts. It probably isn't quite as quiet, but is close.
 

tongsli

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Location
Baltimore, MD
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2000 Jetta TDI, 2004, Jetta Wagon TDI PD
I've always thought my A4's were loud. Not engine but road noise loud. Even my new, off-the-lot Golf. Interested in the outcome of this thread. Road noise is always a high priority when buying new tires. Michelins are usually quieter than most, IMO.
I had a 99 Passat GLX before this TDI and people used to say how quiet the ride was with the windows closed. I love my TDI but miss the quiet ride of the Passat.
 

Judson

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Jan 18, 2001
Location
Cheyenne, WY
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2001 Jetta
Hey Lito -

Well, I'm not sure about the wheel well plastic - are you talking about outside the car or inside?

The entire interior plastic trim is being removed to install the materials; this includes whatever is lining the rear wheel wells. Also, on our cars, the door windows have to be removed to properly install the materials.

As for the headliner - not much can be done if you have a sunroof, as there's not enough space for anything other than the tiles.

I had already done underneath the carpet when I replaced with a used black one; it didn't make much of a difference. This includes as far up under the front foot wells as I could go.

I have a skidplate yet to be installed. There's just not enough on the roads out here to worry about killing my oil pan. AND it would drop the clearance underneath to unacceptable levels. I do believe it would drop noise levels some, preventing the engine noise reflecting off the pavement. Probably a slight incremental difference, but with an engine cover (which I'll put back on), and a different hood liner, it may add up.

I may purchase a used OEM (plastic) underbelly tray and sideskirts and install that. I threw mine out years ago when it just got too ratty. I think this actually makes a big difference on holding in the engine warmth, which can be a big thing considering Wyoming winters.
 

tongsli

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Location
Baltimore, MD
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2000 Jetta TDI, 2004, Jetta Wagon TDI PD
Hey Lito -

Well, I'm not sure about the wheel well plastic - are you talking about outside the car or inside?

The entire interior plastic trim is being removed to install the materials; this includes whatever is lining the rear wheel wells. Also, on our cars, the door windows have to be removed to properly install the materials.

As for the headliner - not much can be done if you have a sunroof, as there's not enough space for anything other than the tiles.

I had already done underneath the carpet when I replaced with a used black one; it didn't make much of a difference. This includes as far up under the front foot wells as I could go.

I have a skidplate yet to be installed. There's just not enough on the roads out here to worry about killing my oil pan. AND it would drop the clearance underneath to unacceptable levels. I do believe it would drop noise levels some, preventing the engine noise reflecting off the pavement. Probably a slight incremental difference, but with an engine cover (which I'll put back on), and a different hood liner, it may add up.

I may purchase a used OEM (plastic) underbelly tray and sideskirts and install that. I threw mine out years ago when it just got too ratty. I think this actually makes a big difference on holding in the engine warmth, which can be a big thing considering Wyoming winters.
The belly pan definitely keeps things clean underneath especially salt. As you know I put the smaller oil pan cover on my wife's TDI and kept the plastic belly pan on her car.

I lined the side skirts with dyna mat as well.
 

Judson

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Cheyenne, WY
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2001 Jetta
Feedback time: the shop did about as well as they could given that there is almost no rooms in the doors to put soundproofing in without preventing the windows from rolling down.

But this means now that all of the sound comes from the doors and the engine compartment. As a result there really is no difference at all.

My door seals are shot so that is the next step.
 

john.jackson9213

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Miramar, Ca. (Think Top Gun)
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1996 B4V
Judson - You don't pull any punches do you. No difference at all or now you notice different things? Like the door seals?
Reason I ask is: When I went to the long (.622) 5th gear, the engine noise dropped way down. Result was that I started to notice other noises. The driver side door did not fit right so I had lots of wind noise. Fixed that, then noticed I had a lot of road noise that changed depending on the street surface. Since I need to replace tires soon anyway I took note of your comments about Michelin tires.

Which Michelin tires would you suggest for lower noise??
 

Wankel7

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Indiana
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2003 Jetta Wagon
Feedback time: the shop did about as well as they could given that there is almost no rooms in the doors to put soundproofing in without preventing the windows from rolling down.

But this means now that all of the sound comes from the doors and the engine compartment. As a result there really is no difference at all.

My door seals are shot so that is the next step.
Drive you actually buy a sound level meter? Test for results on the same stretch of pavement type? Based on what I saw inside the door when I replaced the speakers there is plenty of room. The glass has to come out though.
http://sounddeadenershowdown.com/vehicles/volkswagen-jetta-sedan-1999-2005
Reading the supply list for the door there is a lot of materials that can go in.
I have installed that peel and seal stuff from HD on the inside of my wheel well liners. A few layers on them. I feel like they make a difference in noise. In the spring when I pull the liners to rinse behind them I will go for a drive with them off and see for sure.

Installing a .658 gear was great for noise though!
 
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LMJ

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Virginia
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2000 VW Golf
Folks -

I'm paying a local shop (Stitch Headz here in Cheyenne) to install the soundproofing materials I bought from sounddeaningshowdown.com about two years ago.
Noise has always been an issue with me, so I'm happy to see that someone is posting about it. Can you elaborate on the type of materials that you bought 2 years ago. What did you buy? Does it include anything in the wheel wells?
 

Wankel7

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Judson

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Cheyenne, WY
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2001 Jetta
The doors were taken apart and the glass removed. Using the "windowing" technique was not possible as there wasn't enough room. Some soundproofing was installed, like the tiles.

Really, I feel like with the exception of the doors the car is pretty well done.
 

inKryptic

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Maryland
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I put Cooper CS5 tires on last week... the difference is amazing. Highly recommend. No observations yet on wear patterns, obviously
 

dremd

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May 31, 2007
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South Louisiana
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06 sprinter. 03 jetta wagon premium with 6 speed ALH swap, 14 JSW
I ran CLD on outer door skin, a few bits CLD on inner door skin (lots of curves not much benefit here), a little on the door card + decoupling foam + MLV between the door card and the inner door skin on my last car. No problems whatsoever.

Edit: it was a 2000 with 04 door cards, I have no idea if that makes any difference or not.
 
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