TheSamba.com :: View topic - Dynamat Sound Deadening Testing Before and After

Wed Nov 14, 2012 10:20 am

Actually, there is no verdict really. All this thread demonstrates is that adding Dynamat to the engine cover, cargo area, and under the rear seat does almost nothing to reduce noise up front, and at best, reduces noise for the rear passengers at lower frequencies 3-5db.

Until myself, or someone else repeats this test and treats the front area, all that exists is anecdotal evidence. On that front, I've read more than one post here that said words to the effect of "I applied product X on the rear bed and the difference was amazing" My tests show that at least with regards to $300 of Dynamat, the difference is just barely noticeable.

Christopher's use of the product B-Quite V-comp makes sense with respect to it's description: "Vcomp is a noise barrier composite consisting of a 1/4" absorber foam with a black urethane film facing, a 15 mil lead barrier and a 1/4" thick foam decoupler. It has a total thickness of 1/2", weighs approximately 1 lb/sq. ft. and it is highly moldable to form to the contours of your vehicle."

I'm tempted to tackle some areas up front and test in the same way...

Wed Nov 14, 2012 11:17 am

I guess so. Your original question was sort of lost to me. I wouldn't spend the money on dynamat. For me, the most important thing to cancel noise is going to be the MLV foam. Driving around without my back cushion tells me that in an instant.

Wed Nov 14, 2012 11:32 am

Yep, the rear foam in place is more effective than the dynamat by a long shot. I didn't test it as covering the van in 5" of foam won't happen!!

Bquiet's Vcomp on the other hand lists an STC rating from between 15db at 125hz to a high of 37db at 4Khz. That deserves a test.

I just ordered some up. I'll be testing it up front.

Wed Nov 14, 2012 2:42 pm

dlb154 wrote: For what it's worth:...I did below both door panels and below the carpet (on the metal below the floor padding). I didn't have any tools to measure the results other than my ears and can say it was well worth the effort.

I've done the low-hanging fruit of the door panels and engine deck, and am next going to tackle under the front carpet.

Did you have to replace or get rid of the stock foam padding there? Does the fatmat fit OK under it? Anything better to replace that with?

Ultimately I want the carpet to fit like factory again.

Thu Nov 22, 2012 1:13 pm

Just received a pile of Bquiet Vcomp: http://www.b-quiet.com/vcomp.html

The material claims:
Transmission Loss, in dB:
15 @ 125Hz
17 @ 250Hz
21 @ 500Hz
28 @ 1KHz
34 @ 2KHz
37 @ 4KHz
STC = 27

Any requests in terms of testing? This time around, I'm thinking of focussing on testing/treatment up front vs the rear. I have enough material to do the entire floor, firewall etc. front to back.

Thu Nov 22, 2012 2:16 pm

use that & a sound deadener up under the dash and measure

Wed Nov 28, 2012 9:15 pm

Still adding sound reducing stuff as I go. The walls are done and I've finished the wiring demolition of the old stereo, alarm and dual battery system and now running new power cables in flexible conduit where possible.

After a road test with only the rear seat and closet cabinet loosely in place, it was much quieter but still significant road noise on the worn wheel rut sections of our Northwest Freeways. Trying to locate the noise, it seemed that most of it was coming through the floor in back and under my seat. So in preparing to put cabinets back in, I decided to replace the factory Westfalia hard floor with some sort of rubber flooring with no seams.

After removing the factory floor, I saw that the floor sat on the high points of the factory steel pan with nothing in the voids between, so I set out to fill in the low points with some of the thin insulation I used in the walls. I used 2 layers to build to the height of the high spots using a 1-3/4" wide strip for the bottom of the void and a 2-1/4" wide strip at the top layer using double back carpet tape.

In searching for a rubberized 3/8" thick flooring, I was running out of time and patience so following a tip about using a Horse Mat, I found a 1/2" thick 5'x7' mat for $62. Cheap enough that I could change later if it didn't work. I was afraid it would smell like old tires (which I'm sure it was made of) but pleasantly surprised that I don't notice it.. At that size, I was able to cut a single seamless floor at 5'x5' that left a 1 inch void at the firewall and behind the stove cabinet for conduit runs and ???

I've sprayed cavity wax at all edges of the floor in hopes of preventing any water from working it's way under the floor mat. Also tossed the factory cheap filler materials that were under the rear seat and cabinets. the "groove" in the rubber floor run lengthwise to the van so any water spill that makes it to the edge at the back will find that 1" space at the firewall and can be removed with the wet vac. The hole at the water tank has been sealed with "The Right Stuff" and will get a glob of plummer's putty to fill the rest as the tank gets set in place.

A definite improvement in sound reduction but I will not know the true ability until all of the cabinets are back in... So in the meantime, here is a little video I made to show this stage of my remodel....:

Thu Nov 29, 2012 7:55 am

I have not read this whole post, so maybe someone has mentioned this, but after many years of insulating, sound deadening etc... It seems to me that until someone comes up with a front fender insert, the front will remain loud.

A while ago I had to do some work to one of my cars and had to remove the plastic fender well insert, it was incredible how loud it was with it removed.

Sitting above a wheel at 65-70 mph is loud on any vehicle, take care of that wheel well and things will get much quieter.

Thu Nov 29, 2012 9:02 am

2ply, that is really nice work. I encourage you to post it to a flooring thread or start a new Rubber Floor thread so it doesn't get buried!

Thu Nov 29, 2012 9:02 am

Would just the plastic wheel insert work, or would a rubberized compound applied to the metal be better? Seems like a plastic insert wouldn't block much noise, but I have never tried that type of solution so could be wrong.

Thu Nov 29, 2012 9:12 am

tschroeder0 wrote: I have not read this whole post, so maybe someone has mentioned this, but after many years of insulating, sound deadening etc... It seems to me that until someone comes up with a front fender insert, the front will remain loud.

A while ago I had to do some work to one of my cars and had to remove the plastic fender well insert, it was incredible how loud it was with it removed.

Sitting above a wheel at 65-70 mph is loud on any vehicle, take care of that wheel well and things will get much quieter.

tarandusVDub wrote: Would just the plastic wheel insert work, or would a rubberized compound applied to the metal be better? Seems like a plastic insert wouldn't block much noise, but I have never tried that type of solution so could be wrong.

http://www.busdepot.com/251800010

I have these and while they do block a small amount of noise, it's not very significant. I am going to pull mine out an add a sound barrier to them to see if that helps.

Thu Nov 29, 2012 9:22 am

tarandusVDub wrote: Would just the plastic wheel insert work, or would a rubberized compound applied to the metal be better? Seems like a plastic insert wouldn't block much noise, but I have never tried that type of solution so could be wrong.

I coated Dixie's fender wells (and more) with roofing cement and road and tire noise was greatly diminished. Its especially noticeable when driving in the wet which we do quite a bit here on the coast.

Sticking a 1/4" styrene sheet to the cement under the steps would have been a good addition. Thanks for the idea! ;)

Thu Nov 29, 2012 9:26 am

Christopher Schimke wrote: tschroeder0 wrote: I have not read this whole post, so maybe someone has mentioned this, but after many years of insulating, sound deadening etc... It seems to me that until someone comes up with a front fender insert, the front will remain loud.

A while ago I had to do some work to one of my cars and had to remove the plastic fender well insert, it was incredible how loud it was with it removed.

Sitting above a wheel at 65-70 mph is loud on any vehicle, take care of that wheel well and things will get much quieter.

tarandusVDub wrote: Would just the plastic wheel insert work, or would a rubberized compound applied to the metal be better? Seems like a plastic insert wouldn't block much noise, but I have never tried that type of solution so could be wrong.

http://www.busdepot.com/251800010

I have these and while they do block a small amount of noise, it's not very significant. I am going to pull mine out an add a sound barrier to them to see if that helps.

How did they fit, Chris? A lot of fussing or pretty straightforward?

Thu Nov 29, 2012 10:14 am

Jake de Villiers wrote: Christopher Schimke wrote: tschroeder0 wrote: I have not read this whole post, so maybe someone has mentioned this, but after many years of insulating, sound deadening etc... It seems to me that until someone comes up with a front fender insert, the front will remain loud.

A while ago I had to do some work to one of my cars and had to remove the plastic fender well insert, it was incredible how loud it was with it removed.

Sitting above a wheel at 65-70 mph is loud on any vehicle, take care of that wheel well and things will get much quieter.

tarandusVDub wrote: Would just the plastic wheel insert work, or would a rubberized compound applied to the metal be better? Seems like a plastic insert wouldn't block much noise, but I have never tried that type of solution so could be wrong.

http://www.busdepot.com/251800010

I have these and while they do block a small amount of noise, it's not very significant. I am going to pull mine out an add a sound barrier to them to see if that helps.

How did they fit, Chris? A lot of fussing or pretty straightforward?

The fronts are a pretty tight fit, but require no fasteners. The left rear fits pretty good, but could maybe use a fastener or two to be 100% secure (although I have about 2000 miles on it without any fasteners and it hasn't moved, so maybe fasteners aren't necessary). The right rear doesn't fit well at all. I tried and tried to get it to seat properly. I even used a heat gun to reshape parts of it, but in the end, I got frustrated and just tossed back in the garage and haven't readdressed it yet.

Thu Nov 29, 2012 10:44 am

Christopher Schimke wrote:
The fronts are a pretty tight fit, but require no fasteners. The left rear fits pretty good, but could maybe use a fastener or two to be 100% secure (although I have about 2000 miles on it without any fasteners and it hasn't moved, so maybe fasteners aren't necessary). The right rear doesn't fit well at all. I tried and tried to get it to seat properly. I even used a heat gun to reshape parts of it, but in the end, I got frustrated and just tossed back in the garage and haven't readdressed it yet.

I have them too, and had pretty much the same experience. The right rear just doesn't fit properly out of the box. I got it to work OK with some trimming. It's nice and solid now. I suspect the fuel filler pipe is in the way, and I'm not sure if a 2wd will have the same problem. Is yours a 2wd or Syncro, Chris?

I also had to heat up and reshape the front lower inner corners to avoid rubbing at full steering lock. They only needed to be bent out of the way a few degrees, and if one runs stock tires, I doubt this will need to be done.

All told, it took about an hour. No difference in noise levels, but they do keep the mud and rocks out of the corners of the fender wells. Worth it for that.

Robyn

Edit: I suck at speeling.

Thu Nov 29, 2012 12:09 pm

Crazy! I had no idea they existed, thanks!

Thu Nov 29, 2012 1:51 pm

Now if only a few would do the before/after testing! 2ply, the rubber floor I suspect would be very effective, likely effective more than the vcomp I have sitting in my garage. The wheel wells up front, even in my 90 have basically nothing over them except for the carpet glued in place. Unless the liners are air tight and back-filled with insulation, I wouldn't expect much of a reduction.

Thu Nov 29, 2012 3:20 pm

I have the ABS fender liners (2pr), and thought I was an idiot, because the Right Rear ones don't fit on either the 2WD van or the Syncro. The other 3 are fine. They hit the shock in a bad way and can't properly seat.

I am also in the midst of installing a Carat interior into a 87 Syncro. When I removed the door panels in the syncro, I was SHOCKED to see there was bupkiss for deadening. This one doesn't even have the sticky tar boards! Maybe the guy that put them in was in the bathroom when my van rolled on thru, but they are not there at all.

Furthermore, there are some inner door panel pieces that are bent over and come close to the outer panels (1/4" or so). At the factory they had a caulk like material "connecting" the 2. In my 25yo rig, it had shrunk and wasn't even touching! It rings like a drum when you rap any panel, and it is quite loud to drive for obvious reasons.

The Carat had tar boards, AND had fiberglass insulation behind the door panels.

Yesterday I finished all the body mods to accept the Carat stuff. I'll take some pictures. We also just added some sound deadening materials to our products, and will be using them to deaden the panels in the Syncro.

I have a lot of Car Audio experience, and had worked with Richard Clark and Dave Navone back in the day. I learned a lot from them, some of it was completely opposite to "popular opinion".

I already put silicone connecting the inner and outer panels, that will help a little bit. I'm also going to put the sound deadener on all flat panels under the door panels, since there is nothing there now. Then I'll transfer the fiberglass, and put the plastic panels on.

Up front will be a separate project, but I'll pull a seat and give a good look around up there. From my previous experiences, the front wheel wells look like a really bad source of tire and road noise. Those are single panel and have no supports, for a nice resonance to get going. I'll likely use the same deadener in there. Same for under the carpet up front.

I have some new high end front speakers coming, and will treat the door properly when the panel is off for the speaker install.

I'll report back when I have more info, but these changes should be quite dramatic in the driving experience of this thing. I'm not going to use a sound meter or anything like that, I did that 20 years ago and have a good grasp on what to do already. Deadening stuff that already has foam on it is a complete waste of time (my opinion). Just have to fill gaps and prevent panels from vibrating. If you had a seat where the upright and lower had a gap in them, you will get a lot of noise passing through the gap, so it's best to close that with SOMETHING.

Thu Nov 29, 2012 4:47 pm

denwood wrote: Now if only a few would do the before/after testing!
I did before and after testing with some of the most amazing listening devices ever made - my ears! ;) 45 years as a musician and luthier has honed and refined their natural abilities. When I say my van is quiet enough to converse in normal tones at 65-70 mph, you can take that to the bank.

Quote: Unless the liners are air tight and back-filled with insulation, I wouldn't expect much of a reduction.

Then you'll be pleasantly surprised by the results when you smear half a gallon of roofing tar in each fender well. ;)

Thu Nov 29, 2012 5:21 pm

I guess what I'm saying here (as a musician and audiophile myself!!) is that my goal is to replace anecdotal with measured results. A db meter alone is of limited use..as all it measuring is peak.

$250 of Dynamat covering the entire rear of the van is pretty much a waste of time. The question now is, what is the best buzz for one's buck up front. My van is quiet enough up front for normal conversation, stock. It's sound profile is similar to our 03 CRV...posted back a few pages.

Jake, the tar thing makes sense, however in theses climes, the rust situation dictates anything under the van is viscous, self healing and applied every year or two. Anything that can trap water between itself and the body is likely a safer bet where winter salt is not an issue.