How to Quiet Road Noise in a Car

It can be really annoying to try and talk or carry on a conversation in a noisy car.  Some vehicles are better than others.  A Tesla is absolutely whisper quiet due to its electric motor; however, Jeeps and trucks are often very loud.

In this article I want to share some of the things you can do to DRAMATICALLY (not a small difference) reduce the road and engine noise in a vehicle to make it much more pleasant to ride in.

The Number One Way to Reduce Road Noise

By far, the best thing you can do to reduce road noise is a very simple fix which really doesn’t cost very much.  It’s called Dynamat.  It’s a foam shield that you put under your floor mats under the two front seats.  This soaks up sound coming from the tires from entering the cabin.

FatMat is available on Amazon and I can totally recommend it. Awesome product. Click to check it out.

However, Dynamat is really expensive, and there’s nothing about it that makes it any better than the cheaper foam shields you can buy on Amazon.  This FatMat sound deadening foam is available on Amazon and is half the cost of the Dynamat (Aff. link).  It gets excellent reviews, and I hear that it’s just as good.

The install takes about one hour and requires absolutely no special knowledge.  If I can do it, you can do it.  You simply take out your floor mat, apply the mat, and you’re done.  The sound deadening foam has an adhesive on one side so you don’t even need to mess with glue.

How much sound deadening you get depends on (1) how loud your car is to begin with, and (2) how much area you cover with the foam.  After you do the bottom of the floor mats in the front, you can also do the area in the trunk which is where a lot of noise from the rear wheels comes through into the car.  This is especially true if you have a large flat trunk area.  If the seats of your vehicle extend almost to the back of the vehicle, then doing the foam in the back will make less difference.

The Belt AND Suspenders Approach to Auto Sound Deadening

If you’re REALLY fed up with road noise, or if you have a problem with heat coming up from the floor panel of the car, then you might consider also adding reflective insulation under the foam.

Reflective insulation will block 98% of the heat coming from the floor board of the car, and will also provide sound insulation.  I was surprised at how much sound deadening this adds to the vehicle.  I thought after seeing the tinfoil-like insulation that it wouldn’t do much for sound, but I was wrong.

Read through the Amazon reviews of this reflective automotive insulation and you’ll see that nearly every reviewer comments on how surprised they were at the difference it made in the soundproofing of the car.

The cool thing is that you can layer this UNDER the foam from step one of this tutorial if you want to go belt-and-suspenders.  You’ll just need to buy 3M General Trim Adhesive and spray it on the floor of the car, then place the reflective insulation on the adhesive.  Once that dries, then apply the foam (which has glue on one side already) to the top of the insulation.  This way your car will be as silent as possible.

Where to Apply Sound Deadening Products to a Vehicle

As I mentioned before, the best place to put the sound deadening stuff is under the driver and passenger floor mats.  This is because it’s where you’ll be in the car, and will block most of the sound coming from the tires.

This is also an important spot because the floor panels act like a huge sound diaphragm that makes the road and tire noise resonate throughout the cabin.  It’s like when you take your iPhone speaker playing a song and it’s quiet, and then you set your iphone into the cup holder of your car and it sounds twice at loud.  The cupholder (just like the floor board) acts like a huge sound diaphragm.

The second most important spot to cover is under the back tires.  If you have a Jeep Cherokee style vehicle with a large flat trunk and only two rows of seats, then this is an area where sound deadening is a MUST.  This is a HUGE sound diaphragm for making amplifying sound, so you really need to cover under the floor mat in the trunk.

The third area to focus on is under the floor mats in the rear row of seats in the vehicle.  Typically there is no axle running here or wheels on the sides, but it’s still a large diaphragm.

The last area to work on is really only important if you want to go crazy on soundproofing your car–the doors.  Jeep doors are notoriously thin, so deadening them will really quiet the ride.  However, you have to remove panels from the doors and take things apart, so it’s much much harder to do than the other projects.

How to Get the Best Sound Deadening Application

Imagine you are trying to soundproof the windows in your home.  If someone were outside talking, the window would block most, but not all the sound.  Now imagine you open the window just a TINY crack.  Now it will sound like there is no window between you and the other person at all.  Even a little crack lets plenty of sound through.

The most important thing you can do when applying a sound deadening kit in your vehicle is to be certain you don’t leave even the tiniest gap between sheets or cuts.  cover the ENTIRE floor area and even up the sides a bit if it won’t show.  Use the tape to cover any seams.

What Kind of Sound Deadening Can You Expect?

I haven’t done any actual scientific testing, but I would say just putting down the sound foam alone can cut out about 40% of the road noise on most vehicles.  The louder your car is to begin with, the easier it will be to notice a significant improvement.

Older vehicles tended to have larger floor areas with less insulation, so if you drive something with a few years on it, you’re likely to see a HUGE improvement.  If you drive a newer car and just want it 15% or 20% quieter, you can probably achieve that too without any trouble.

I might recommend downloading a decibel meter app on your phone (there are lots of free ones in the App Store) and driving down a road near your home at a set speed.  Then do the soundproofing and drive the road at the same speed again.  Be sure to turn off AC/Heat in the car.  I’d love to know in the comments what kind of numbers you get.

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