dhmcfadin

Luxury liner pro

woodall01

Thanks, I am assuming you did the entire back of the truck?

nineball

a CLD or constrained layer damper is the first step. applied directly to metal it needs roughly 25% coverage on large flat panels, others areas as needed. while it may make the vehicle sounds more quiet to the ear it does not block any sound. it lowers the resonant frequency of the metal panels and absorbs some of the vibrations they make and converts it to low level heat which is dissipated by the aluminum layer on top.

the next step would be a decoupler, typically CCF or closed cell foam. this does block some of hte higher range of frequencies but it's purpose is to be between the CLD and the MLV.

MLV, or mass loaded vinyl, is the part that actually blocks noise. this, like the CCF, needs 100% coverage including sealing all seams (overlap them and glue with contact cement, same for the CCF). it typically weights about 1lb/sf.

some companies combine the CCF and MLV into one two layer product. i prefer to install them separately as it makes the install easier.

most people take the first step, think the noise is being blocked and stop. there is nothing wrong with that, but it is the equivalent of only putting on a sock and then going out for a run - sure, you can make it back home but if you put on a shoe the results would be a lot better.

dhmcfadin

Only the lower portion to eliminate the vent noise. CLD followed by sandwiched CCF AND MLV.
Attachment 567094

HushCarAudio

He used both a vibration dampener called Damplifier Pro and also a closed cell foam with heavy rubber mat called Luxury Liner Pro. The combo works extremely well together. Foil tape is sometimes used for the seams to join everything together and further reduce the sound waves from creeping in between the seems. You can also use more vibration dampener instead of foil tape to do the same thing. It's actually much thicker material so should work better than foil tape.