All Vehicles Sound Deadener Technology

[Amskeptic]

Our understanding is evolving. Coating the interior of your bus with silvery Dynamat, apparently, is a waste of money and resources.

I have seen the multi-pronged approach spoken of in this link throughout the Lexus LS400, which is a quiet ride.
Colin


http://www.sounddeadenershowdown.com/

[chitwnvw]

k.

Seems like they are a sales site. The Mass Loaded Vinyl barrier technology sounds interesting, and jibs with the results I've seen with the sound deadener, that it deadens the panels to touch, gives a nice door shutting sound, but that noise on the highway is still excessive.

Thanks for the link.

[hambone]

My camper howls, rattles, vibrates. The windows clatter. I don't think sound deadener is going to help. 40 years of clunking down bad roads. Even the metal in the bed vibrates at certain speeds. It's not as bad in a fully loaded bus, but empty forget it. I've just learned to live with it.

[glasseye]

Noise over time results in at best, fatigue, at worst permanent hearing loss.

This is a topic of great interest to Sprinter cargo version owners. An empty "tin can" van is essentially a excellent bass drum and, as satchmo will testify, Frito creates a truly awful driving experience on rough roads.

Recent posts on my Sprinter forum indicate significant improvement in ride quietness resulting from the application of panel-deadening materials similar to those available from mobile audio dealers but at a fraction of the cost of the dedicated materials.

Lowe's sells "Grace Vycor® Butyl Self-Adhered Flashing" which several Sprinter owners have applied to the interior of their vehicles and have succeeded in reducing noise considerably. I recently purchased about 100 square feet of this material for $60 and will begin to apply it soon. I'll report on the results.

[Sluggo]

I covered the interior of my Bus with sound deadener mats (R-Blox, MatZilla & E-Dead). 2 to 3 layers in the nose, roof, floor, wheel wells & around the engine. Then used closed cell, plastic coated styrofoam sheets. I know I went way overboard on the mat stuff. But my Bus is the quietest I've ever been in. I can barely hear the engine. With the windows up, road noise in minimal. New seals helps too.

[fancy pants]

I am following this with great interest. I just finished removing the interior on my bus, and after Willy does his magic I will be looking into some sound deadening materials.

[Amskeptic]

Thank you, chitwnvw.

This is an interesting topic. There was a site from several years ago where this guy went ape on his bus going so far as to shoot expanding foam up in the a pillars and pretty much entombing the sheet metal of his entire bus. He was after both the sound deadening and heat insulating properties of the materials applied. Once done, he sold it. Went too far, I guess.

As I looked at this link (sales huckstering duly noted), I realized that Lexus really had done something different. It was the quietest passenger car sold at the time, yet it weighed only 3,700 lbs. It did not have the heavy applications of asphalt as noted on my '62 Lincoln, the carpeting looks light, the doors are light, yet the car is so hushed. The notion of both dampening sheet metal resonance and decoupling interior surfaces without just blanketing everything intrigued me. The Lexus rings with heavy rain on the roof. That is when you know it is a light tin can in reality.

I had applied Dynamat to the floor of the Road Warrior in two layers, including the wheel well stampings, and I did the cargo floor and the gas tank bulkhead. I was very sorry that I did that. Apparently, I was not fully cognizant that I had removed all the nice higher frequencies of the engine at work, and I was left with an oppressive thumping-under-load coming up through the floor. So I was wondering, what the h**l? How do luxury cars that weigh only a couple of hundred pounds more, half of which is in the engine alone, do it? Well, when I look at the thin plastic flooring of the Lexus sitting on a dense foam backing that is formed to the contours of the floor that is dampened with Dynamat only in the center areas, there's an answer.

After the Lexus was introduced, Mercedes went hog-wild trying to regain the luxury quiet supremacy, and introduced the double-pane windows W140 Huge Pig weighing in at 4,960 lbs, but alas, it still sucked.
Colin
(and the brand new Lexus LS460 now weighes 4,365 lbs and came in dead last in every category but silence and engine thrills in the comparison with MB, Jag, Audi, BMW . . nice one Toyota)

[glasseye]

So I was wondering, what the h**l? How do luxury cars that weigh only a couple of hundred pounds more, half of which is in the engine alone, do it? Well, when I look at the thin plastic flooring of the Lexus sitting on a dense foam backing that is formed to the contours of the floor that is dampened with Dynamat only in the center areas, there's an answer.

My take-away from a long phone conversation with an expert in this field was that, in addition to the wheel wells, the floor is critical to noise reduction and de-coupling the floor pan from the interior flooring is what's required. I'll be pulling the floor in the Sprinter and isolating the flooring material from the sheet metal beneath with closed-cell foam.

They mentioned that Dynamat and other solutions like mass-loaded vinyl sheeting needs to be applied only in the center of panels to damp the panel resonance.

Other Sprinter forum posts refer to the Sprinter's poor door sealing to the airstream and suggest using residential weather stripping to fix this. I noticed on a Vanagon recently that the doors were sealed right to the edges, where the Sprinter has the door sealing recessed an inch or so from the door edges. This creates a lot of noise at cruise.

Loaded with 500 lbs of fiberglass insulation recently, Frito was incredibly quiet. The bass drum noise totally disappeared and I was left with door wind noise, centered around the A-pillars. I noticed this same wind noise with my Bay. It should be an easy fix with good door sealing.

[Amskeptic]

They mentioned that Dynamat and other solutions like mass-loaded vinyl sheeting needs to be applied only in the center of panels to damp the panel resonance.

I think they agreed that Dynamat needs only to dampen the panel resonance, but the mass-loaded vinyl sheeting needs to actually perform some contiguous barrier, isolating via complete coverage?
Yaah?
Colin

[justgimmecoffee]

Yes, I agree quiet is good and going deaf is bad. But, there is something to be said for hearing your engine. When I was driving my newly rebuilt engine that was leaking oil like a sieve, I could hear a difference when it got low on oil. The leak is fixed, but it convinced me not to get a radio, just so I could hear the engine.

I like the soundproofing idea up front.
I appreciate the link Colin. I wish his site had directions or links to directions.

[justgimmecoffee]

I'm getting ready to remove the nasty carpet from my bus and thought I"d do a little sound reduction while I've got stuff out. I like the idea of using hardware-store materials (as opposed to buying the Good Stuff online. Its the shipping that kills that), but there's health concerns about butyl and asphalt roofing materials that aren't meant for camping interiors.

Its hard to separate the good information from the advertising. Or the bad ideas. This writeup at Type2 has roofing materials and large hunks of fiberglass insulation in the walls. I'm not sure that's wise. http://www.type2.com/library/heat/intrir2.html

[glasseye]

Here's a report on my latest research and testing. Colin, did you investigate the noise removal technologies in your Lexus?

I did a test with the Lowe's flashing I mentioned in a previous post. Zero effect. Nada.

Apparently, de-noising requires a combination of effects. Damping, isolation and blocking. Critical areas are: floor, firewall (front engine), doors and wheel wells.

High frequencies are easy to block, low ones nearly impossible. That's why Colin was left with the thumping, and that's why we can hear those idiots with their subwoofers from blocks away.

Damping is well done by "Damplifier" and its brethren, but it doesn't block or isolate much. Plus, it's very spendy. A little bit in the center of a panel damps vibrations adequately. I bought a couple of square feet and it does work at changing door slams into something nicer than the tin can sound we love to hate.

Isolation is apparently well done with closed-cell foam glued tightly to the previously damped panels. www.closedcellfoams.com I'm gonna go with a roll of 3/8ths "Volara". Closed cell foam won't retain or trap moisture, yet offers good insulation of sound and heat.

Blocking can be accomplished with lead sheeting (!) or mass loaded vinyl. At $3.25 a square foot, it'd better work! Frito has a lot of square feet.

[Amskeptic]

Here's a report Blocking can be accomplished with lead sheeting (!) or mass loaded vinyl. At $3.25 a square foot, it'd better work! Frito has a lot of square feet.

Keep us posted! I am curious to see if I can put in slip-in noise cancellation technology in the BobD, though with my summer supplies in the interior, it is a very nice sounding ride.
Colin

[hambone]

I've noticed that too. A full camp-load makes for a quiet bus.
It also seems like the bus was designed for maxium ride comfort and handling when loaded as opposed to empty.