IMPORTANT

Foam doesn't do anything unless there is a very dense material mated/covering it. The foam just allows space for air to exist. Then the dense material decouples that air from the cabin. Air is the best sound insulator only if it is decoupled.

And yes, Cascade is the easiest stuff out there to install. I love it, it's just a bit pricey for some people.

 

dont think the dynamat didnt work, it may not be best tool for the problem. Remember this is road noise from your cars tires, this noise is airborne AND this noise is structure borne (the tire vibration is transferred to the mount points of the suspension and then to the entire body of the van) the dynamat will do 2 things 1- act as a sound transmission loss (barrier) as measured by ASTM E90 (associated with mass load) and 2) Damp the amount of energy added to the vehicle as measured by ASTM E756 the effectiveness will be limited to the area treated
to eliminate the road noise you are generating you need to do 1 and 2 above. The dynamat and foam together would be using constrained layers and that will have some effect. This may not be all that cheep to fix... I like to use jute as much as possible as it is good at sound absorption (ASTM C423) and is cheep.

Cars come from the factory with jute, damping goop, and a hard septum under the carpet to block noise... cargo vans not so much

 

this is why I generally go crazy when people on the forums call ANY material a sound deadener, because no single material does everything to stop sound intrusion or exit.

 

well very nice answer!! Thanks.

The van is actually a passenger van... It had jute, or underlay, but needed repalcing. As soon as I lifted the carpet for the first time it stayed on the floor with the van! The hard septum under the carpet held up OK, but is cracked and worn from being wet so long.. I'm not to sure how long this has been an issue in my van, but suprisingly the floor was not to bad with rust. I had to use a wire cup on a drill in some spots to remove the chipped paint and rust. I applied rust primer, then touch up paint to the bad spots, wiped/cleaned it then added my dynomat material.

I work with buidling materials day in and out, so i have access to try r19 insualtion.. The white commercial grade johns manville insualtion. It will be interesting, and might rot out ina year or two from work boots, etc, but at a price of almost nothing, I think it's worth a try?!?


For the ASTM C423 material. Is this ordered through factory, or available aftermarket?

Thanks

 

ASTM C423 is the only common product here (damping material is only common in automotive applications and SOME sound studios)... it is simply a product that absorbs sound so anything will do it some more successfully than others. Jute is good at absorbing low frequencies which is another reason why it is all over cars (but mostly it is cheap (recycled blue jeans)) for the higher frequencies products like melamine, or urethane foam are pretty good, but the fiberous products are better and cheaper (fiberglass is king over 1000 Hz). The rubatex or neoprene rubber would also be little absorbent but mostly a 'sound path breaker' (ASTM E90) like bradsk88 discussed it helps decouple.

 

I use imn my car some Neoprene foam mainly at the frount of my car and I´m very happy with it. I´d recomendy it!!!