Sound Proofing/Deadening The Cab?
 

I just finished installing a new stereo in my '65 C10. It sounds great when the truck is sitting still, but at highway speed, the road noise, drivetrain noise, and wind noise pretty much drown it out. I recently installed a very quiet exhaust system on the truck. At this point, the road noise is louder than the engine noise. I can turn up the stereo louder, but then I just have a cacophony of music clashing with the drone of the uninsulated truck cab.

So, I'm asking for advice on how to deaden the "metal box" effect, and to sound proof the cab as much as reasonably possible. I'm not looking for competition level sound quality, but I'd like to be able to enjoy some tunes while driving down the highway. While I'm at it, it would be nice to cut down on the heat transfer through the firewall and the floor pan.

When I pull the interior apart for rust repair, I intend to line the floor, firewall, rear cab wall with Kilmat. Then, I plan to install new jute and carpeting. In my son's 1983 El Camino, the Kimat helped to take some of the "ring" out of the metal panels, but it didn't really quiet down the interior as much as we had hoped. I'd like to do better with the C10.

The question is, what else can I do to help seal and deaden the cab?

What materials and techniques have others had success with? Are there any products out there that help with sound AND heat?

Are there other layers that I should add to the floor?

What's the best way to insulate/deaden the doors?

What about the roof? I hadn't planned to install a headliner, but if it will help quiet down the cab, I'm definitely open to suggestion.

Thanks for any advice you can give.

John

Re: Sound Proofing/Deadening The Cab?
 

Foil back stuff is good but a nice fat piece of jute will knock down alot of noise. Inside the door a medium or 1 sheet can be applied center outer panel. Full coverage is not needed. Plug all holes. New seals.

Re: Sound Proofing/Deadening The Cab?
 

Installing a fan clutch made a huge difference on both of my trucks.

Re: Sound Proofing/Deadening The Cab?
 

Thanks for the suggestion. I hadn't even considered a clutch fan. I'll have to put that on my to-do list.

Re: Sound Proofing/Deadening The Cab?
 

Here's from a bit back when I wrote up my impressions of Noico Red from Amazon. I still do like it.
http://67-72chevytrucks.com/vboard/s...d.php?t=814233

Re: Sound Proofing/Deadening The Cab?
 

What brand of foil backed material did you use? I'd like to see how it compares to the Kilmat brand I'm familiar with. Thanks.

John

Re: Sound Proofing/Deadening The Cab?
 

It's funny because the quieter you make it the more noises you can hear. For instance before I made the exhaust super quiet I had no idea how much noise was coming out of my intake and carb thru my 360 degree open element air filter. Then I changed that up and I noticed my alternator was getting loud. The wind noise is a problem but I double weatherstripping the doors helped. I used the squarebody door pieces for that. (I'll find a link). I also used "mass backed" carpet. It adds weight, but it's nice. I made an insulated removable filler panel to block off the lower cab corners where my bottle jack lives. I blocked evey hole in my firewall. I insulated my hood...one thing just lead to another as the ride kept getting quieter and I kept noticing more stuff. And it was totally worth it in my case.

Re: Sound Proofing/Deadening The Cab?
 

Interesting stuff. It looks like it's sold out on Amazon, but there are several similar products at 394 mils. The combination of 80 mil Kilmat and 394 mil sound/heat mat ought to quiet things down nicely.

Please keep the suggestions coming. The more the better.

Re: Sound Proofing/Deadening The Cab?
 

Here's the one on the door edge seals. I ultimately ended up taking it around the whole door.
http://67-72chevytrucks.com/vboard/s...d.php?t=819887

When I did Hoodliner by Dynamat.
http://67-72chevytrucks.com/vboard/s...9&pp=35&page=2

Update: Clutch Fan
 

Member Caseyjones suggested installing clutch fan in place of the flex fan that the previous owner installed. This was an interesting suggestion, because flex fans cool well, but they roar as engine RPM's climb.

Before I started the experiment, I got a baseline sound level reading with my smartphone. At 60mph, radio off, and heater fan off, the cab sound level was 72db.

I had a 7 blade fan on hand, but the clutch on it was for an Oldsmobile water pump. I ran to my local O'Reilly and picked up a compatible clutch.

After the installation, I took the truck for another drive. Again, at 60mph, no radio, no heater fan, the sound level was 72db. The clutch fan didn't change the interior sound level.

Now, the really interesting part is that the clutch fan did change the tone of the engine noise. To my ear, the engine tone is lower, with less of a "roar". The cab is still very noisy, but it's easier to listen to the radio now. It will be interesting to see how future sealing, sound deadening, and sound proofing effect the sound level readings. It will be awhile before I get around to the interior work, but I'll try to remember to update this thread with new readings as I go along.

John

Re: Sound Proofing/Deadening The Cab?
 

Just throwing my .02 cents into the mix.

I spray the bottom the cab with bed liner like coating, then use Por 15 on floor on side, then apply a good thick sound deadener mat, then I get carpet with the mat and add Jute matting to the kick/firewall.

A bit excessive, ya maybe BUT I really like to hear my stereo - funny I say that and if you see the stereo... ya nothing will be louder but I just like to hear and talk to passenger and not need to talk over road noise.

Anyways, just an added thought.

Re: Sound Proofing/Deadening The Cab?
 

Thanks for the suggestions. I saw some of your sound deadening in your build thread and I agree with your approach. My stereo won't be nearly as high-end as yours, but I would like the cab to be quiet.

I'm looking at using these two products in addition to jute and carpet.

Kilmat 80 mil butyl sound deadening mat:
https://www.amazon.com/dp/B0751CBXBT...v_ov_lig_dp_it

Gosche 394 mil sound insulation mat:
https://www.amazon.com/dp/B097JRTRLV...v_ov_lig_dp_it

I've used the Kilmat before and it does a good job of dampening the metal surfaces, but I've never used the thicker Gosche sound insulation. I'm hoping it will help block more of the road/wind noise and tone down the heat too.

Thoughts?

Thanks.
John

Re: Sound Proofing/Deadening The Cab?
 

I believe that was FAT Mat. I have used whatever on sale. That was leftovers. I did some 180 Noico foam on my doors on Dodge diesel Sound Quality truck. Pretty much they all the same. But that big pad can be replaced with cheap jute

Re: Update: Clutch Fan
 

According this quote from the CDC 72DBs can damage your hearing: "Sound is measured in decibels (dB). A whisper is about 30 dB, normal conversation is about 60 dB, and a motorcycle engine running is about 95 dB. Noise above 70 dB over a prolonged period of time may start to damage your hearing. Loud noise above 120 dB can cause immediate harm to your ears."

Keep up the good work. It's totally worth it.
Edit: btw it was this article that helped me decide to go with Kilmat https://soundproofguide.com/fatmat-v...co-vs-dynamat/

Re: Update: Clutch Fan
 

I'm with you 100%. This is exactly why I'm trying to quiet the truck down. I like to listen to music and audiobooks. BUT, I don't want to have to turn the stereo up to overcome the roar of the truck.

For reference, my '21 GMC Sierra is 62db at 60 mph. The listening experience in the GMC is very enjoyable. That's my target. If I can get the C10 down to that sound level, I can live with it. Anything quieter than 62db is just gravy.

Re: Sound Proofing/Deadening The Cab?
 

I like the Kilmat stuff, used it before and it works good. The thicker (goodness that is thick) stuff I have never used before. That is not to say it is not good, just that I have 0 experience with it. It appears you have alot of great suggestions and your thoughts are good no matter direction you choose. Maybe let us all know what way you go and then maybe an update on how it worked out.

Re: Sound Proofing/Deadening The Cab?
 

You're right about the thickness of that material. It's 3/8" thick. If that doesn't quiet the cab down, nothing will!

It's going to be a while before I gut the interior for rust repair, paint, seats, etc. But, when I get there, I'll try to remember to update this thread with final sound level readings.

Re: Sound Proofing/Deadening The Cab?
 

I used Noico from Amazon, worked excellent.

Re: Sound Proofing/Deadening The Cab?
 

Chilli,
Which of the Noico products did you use? Was it the 80mil black/foil material or one of the thicker Noico Red products?

Thanks.
John

Re: Sound Proofing/Deadening The Cab?
 

I've done all the things listed here, dynamat throughout including inside the doors and the back wall, insulation, carpet, the doors are sealed, and it's still loud at highway speed. These trucks are aerodynamic disasters, and the wind noise and road noise is just a fact of life. The windshield is almost straight up and down, and the roof in the front extends past the windshield. Try holding your hand on the roof at 70 mph and you can feel the vibration of the outer sheet metal wiggling. Not much you can do. On a long trip it can get to you a little. These trucks weren't designed to go much more than 50 mph. I think riding in the newer vehicles spoils us, as they are so quiet and the stereos are so good. Also, the only upholstry in the whole truck was the seat. Everything was metal. I love these trucks for their styling and everything else, but I don't think there is a solution for the noise.

Re: Sound Proofing/Deadening The Cab?
 

This is the kit I used..
Noico 80 mil (2 mm) 36 sqft (3.4... https://www.amazon.com/dp/B00URUIKAK...p_mob_ap_share

Re: Sound Proofing/Deadening The Cab?
 

Thanks Chilli. That's almost identical to the Kilmat product we used in my son's El Camino. We followed the directions and covered 60%-70% of the floor pans, firewall, and roof. It definitely took the tin can resonance out of the cab, but it didn't really "sound proof" it very much. When I do the C10, I'll aim closer to 100% coverage, like you did. Then, I'll probably go over that with one of the thicker 394mil sound/heat barrier products.

John

Update: New Door Seals
 

Just before the winter weather hit the midwest, we had a warmish weekend. I took advantage of a rare free Saturday to install new door seals on the C10. I used push-on style seals from Brothers. The new seals are definitely tighter than the crumbling original seals and, just like the clutch fan, the new seals changed the tone/drone of the cab, but they didn't do much to quiet the cab down.

With the new door seals installed, I took the truck for another test drive. At 60mph, no heater fan, no radio, the sound level was still at 72db. The one variable was the wind. There was a 20mph cross wind that day that very well may have added to the cab noise. My previous test drive sound tests were done on calm days. I'll test the sound level again if we ever get another calm day...

John

Re: Sound Proofing/Deadening The Cab?
 

RustBucket,
Thank you for joining the conversation. You're right about the shape of the truck. Great styling, lousy aerodynamics. You mentioned the roof vibration. Did you, by any chance, install Dynamat on the cab ceiling? I know these trucks don't have headliners, like a modern vehicle, but there are aftermarket headliners available. They cover the center section of the ceiling, probably 70% coverage. I'm wondering if a layer of Kilmat and a headliner would help with the roof noise? Thoughts?

Thanks.
John

Re: Sound Proofing/Deadening The Cab?
 

I used Flatline Barriers on mine - https://fpautoparts.com/flatline-barriers
Not that I can find any pics of the install for some reason. :)