Does hood liner reduce interior noise?

[AcampoDave]

I decided to find out. Using a free app on my tablet i measured the interior noise at around 55 mph to be 47db. (With the windows up and a/c on low speed). First I applied Kilmat in 2" strips to the entire underside of the hood. I also spaced the strips at 2" apart figuring I'd have 50% coverage and not weigh down the hood to the point of it closing unexpectedly on my head. This already made the hood feel way less tinny and I hadn't even applied the liner yet.

[AcampoDave]

I used Dynamat Hoodliner applying it in sections with a seam dead center, a seam under each brace, and a seam at each body roll (but you get no pics for that because now the site tells me I am missing a "security token" even tho' I just posted the one above.)
Upon completion of the job, I went and re-drove the same test road and found the truck to be noticeably quieter and I confirmed with the app that I had achieved a reduction of around 4db.

[AcampoDave]

One more try on the pics...

[AcampoDave]

The liner really firmed every thing up nicely and a quick "thump" on the hood with my knuckle showed an obvious difference. I was pleased that the reduction in exterior noise translated to the interior driving experience as well. 4db isn't huge, but it is certainly noticeable. (Sorry for the multiple posts but at least I managed to get you the other pics.)

[Steeveedee]

Just so you know, the sound deadening detection equipment uses a logarithmic scale. 3 dB is ~1/2 the level of noise, so 4 dB is slightly more. 10 dB would be 1/10th the noise level. Any deadening is a good thing.

[AcampoDave]

Yep, I've reached that age where I'm starting to pay the price for my loud hobbies, too many hot rods, Waverunners, jet boats, sanders, grinders...etc. And although I have always protected my ears where power tools are concerned, my ears ring constantly and the doc says its due to high frequency hearing loss.

[Steeveedee]

Shooting guns when young, racing with open headers, and working in the engine rooms of Navy ships, all without hearing protection, has left me with tinnitus, too.

[The Rocknrod]

Originally Posted by Steeveedee

Shooting guns when young, racing with open headers, and working in the engine rooms of Navy ships, all without hearing protection, has left me with tinnitus, too.

Flight decks on Aircraft Carriers for me, catapults and arresting gear. When I first started in the mid 70's you could hardly find a set of sound attenuators that had foam inside or rubber seals. They still kicked you upstairs.

[roll_the_dice]

I feel like your 47db was a good level to knock it down 3 more db's is great. I just tested the noise inside my living room with the a/c running and it averaged 54.7dbs with HVAC air handler blower in an adjacent closet. I hope when I get to cruise again my levels are similar to yours, if not maybe I will try the hood liner approach. Thanks for posting.

[AcampoDave]

For reference, my 2017 Silverado scored a 35db on the same test drive.

[forestb]

I have done absolutely nothing in life and my hearing is just fine.

[AcampoDave]

Originally Posted by forestb

I have done absolutely nothing in life and my hearing is just fine.

That's funny.

[curvedglass]

AcampoDave - Welcome to the ringing world of tinnitus!!

Mine was loud music - how many Spark-o-matic speakers can you get in the cab of a pickup truck! One thing I can still hear is my Father telling me I am ruining my ears.

In 1989 I went to a Lynyrd Skynyrd concert 3rd row from the stage on a Sunday - my ears rang until Wednesday!

[AcampoDave]

Thanks, Tinnitus sucks but I'm getting used to it now.
At the spur of the moment today I tried something kinda funny. I knocked another easy decibel off by shoving foam pipe insulation between the bed and cab right at the bed floor level. It seemed logical that keeping the noise confined under the truck would help and I already had the pipe wrap so...why not.