Sound Deadening

On the maiden voyage of Oscar the ability to talk to the passenger was hindered by the amount of noise echoing through the cab. I invested in a lot of Dynamat to get the noise down to regular conversation level. I took the time to measure the noise level at an idle every step of the way. I will continue to add to this post as I finish out the interior with Dynamat and paneling.  Below is the original decibel level without any sound mat of any kind.


Just for reference a vacuum cleaner is about 80db. So imagine driving in your car with a vacuum cleaner on without the benefit of getting anything clean or driving your dog nuts. Here is the basic overview of the layers I am creating within the cab.

ROOF: Dynamat Extreme & 1/2″ Dynaliner in valleys of metal work
DOORS: Dynamat Extreme (on exterior metal and metal framework)
REAR QUARTERPANELS: Dynamat Extreme & 1/2″ Dynaliner
DASH PANELS: Dynamat Extreme (limited surface area)
BACK WALL: 1/2″ Dynaliner in valleys of metal work
FLOOR WELL: Dynamat Extreme & Dynadeck
UNDER CAB: Dynamat Hoodliner

I started with Dynomat Xtreme on the ceiling and the doors and door panels. Then placed 1/2″ Dynaliner on the ceiling in the valleys of the roof.  It brought the levels down 10db to 69db and I still have the back wall, floor and engine-well to go. Not to mention I am creating panels with felt for the back wall, headliner and door panels to cover the mess of logos all over the sound deadener.

I finished up the back wall with 1/2″ Dynaliner and felt panels. As well as filling in a few spots on the top of the engine well.


I have liner material to put n the underside of the cab as well but the hydraulic lift for the cab has crapped out on me so I need to figure that out. Most of the noise is coming from the engine so the Hoodliner will make the most difference. I know that because after finishing the back of the cab the noise level was still at 69 decibels.


I finished the floor on the driver and passenger side with Dynamat Extreme and then Dynadeck which will serve as the flooring. I was able to order one 72×54 sheet and cut both sides out of it. I made a template out of the box that the Dynadeck actually came in and over the course of a half day went from the cardboard template to the cutting of the material. I used the original cover over the engine tunnel after spraying it with a 3M rubber coating material.


And with that I am down to 64 decibels without door panels, new door gaskets or hoodliner. I should be under 60db with the last remaining items.


I’ve just recently finished the headliner. It consists of 3/16 MDF and is wrapped with the same fabric as the rear panels.


This has brought the cab down to 58, which comes as a surprise since the doors and underside of the cab are yet to be finished.


I continued on the underside of the cab, using both a product call raptorliner then dynamat hoodliner.



At this point the cab was around 53 decibels without door panels. It’s damn quite and I’m really excited to get this knocked out.


  1. Did this help with reducing the heat both for the engine and the outside ambient temperature? Did it help keep the cab cooler with when the ac was running?


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