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.

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