Sound deadening on bed?

I have a cap on my truck. I usually have the back window open with my dogs in the back. It's pretty noisey but has been made much better after installing a gasket around the window.

I have lots of butyl sound deadening left over and I was wondering if installing it under the bed would offer any noticable reduction in noise. Assuming I can actually get it to stick.

 

Maybe get a BedRug?
https://bedrug.com/bedrug-impact-bedliner

What year is your truck? Metal or composite bed?

 

Composite. I have a rubber mat in there already. It's not a huge problem. I wouldn't even care if I didn't have more sound deadening laying aroubd

 

You wont be able to install the sound deadening under the bed as the reinforcing ribs of the composite would make it very difficult.

 

I've not been able to get much to stick to the plastic, either. Tried adhering something to the tailgate plastics without success a few months back.

 

I'm looking at try-ing the same,
for the same purpose -
but I'm planning on dampening the interior of the bed side-walls where I can sand to metal.

any notice-able dampening,
assuming you pulled the trigger?

 

Did you try installing carpet? Should make a difference, much easier.

 

How about of thick layer of spray material (like underbody coating) on other side of bed? Should be relatively easy to apply with long hose sprayer,
adheres to anything, reduces noise....

 

composite is a different material that transmits noise differently. steel works well with mass loading as it's thin and easily vibrates, which creates other sound waves that can sometimes cancel out the desired sound waves. composite is somewhat thick, and doesn't produce sound waves so much, but does do a nice job transmitting noise elsewhere due to it's rigidity. so mass loading it isn't going to work as effectively until getting into obscene amounts because it's not moving the same as a steel panel does.

a bed rug is a good idea-- because the composite is so rigid, it's better to reduce the vibrations entering/exiting it than attempting to dampen the vibrations within the composite.

 

bought dampening material with the intent of dampening rear doors and using excess around the body -
didn't get past the doors before running out.

plan to finish the doors out, then will look to doing some body application.
un-scientific results to follow