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Can I Use Sound Deadening Spray for Car Audio?

When searching for car audio sound dampening alternatives, one worth considering is a sound deadening spray. But should we use sound deadening spray for car audio?

Using a sound deadening spray is an excellent solution for covering unfilled gaps left in the car interior after installing standard sound dampening mats.

Sound dampening spray can be applied to any complicated areas in the body panels that are hard to reach, like tight inner door corners or nonsymmetrical curved shapes, and it gives an even layer of sound insulation.

A sound-deadening spray can also be used as the only filler in the entire cabin. This is however less popular, and most people use dampening sprays together with sound deadening mats or foams.

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In the article below, you will find more information about sound deadening sprays and how to create an exceptional environment for high-quality car audio.

What is a sound deadening spray for car audio?

A sound-deadening spray is a foam that, when sprayed over metal body parts, gives an even application of sound insulation on the whole surface. Using a spray is the most effective way to insulate the car, especially gaps left after installing sound deadening mats or other hard-to-reach places like tight corners inside door panels.

sound deadening spray for car audio

The sound deadening spray allows us to cover the entire surface without leaving any uncovered area.

In addition to reducing noise and vibrations, sound dampening spray is an excellent product for protecting cars from corrosion, rust, salt, or as a heat barrier.  

Although spray can be used as a single product to cover the entire cabin, I rather use it in combination with sound dampening mats. The one I trust the most and can recommend without any doubt is Boom Mat.

It is a fantastic product if you want to reach not covered by insulation mats metal elements not only inside doors but also on the floor and in the trunk.

I have found it an easy and fast way to cover the car interior, and although it requires drying time after applying, it is still quicker than preparing and cutting dampening mats. Most importantly though, Boom Mat is much more effective in tight corners.

Boom Mat dampening spray is available on Amazon, so if you need a really good product, click this link and check the latest price.

One thing to add is the coverage that, according to the producer, is 20 sq. ft. from a can. That depends on the surface, and if you want to cover flat areas like roof or floor, it can actually cover more than 20.

is boom mat good sound deadening spray

Is sound deadening spray more effective than mat?

Sound damping sprays are made of sound dampening particles that are mixed with fluid rubber or vinyl sheets. Such material composition guarantees excellent sound absorption and heat resistance.

The sound damping spray’s overall effectiveness depends on the number of layers applied, and for the best results, it is worth covering the car interior twice.

Below are a few main advantages of the sound deadening spray:

  • Reduce unwanted road noise and car body vibration, especially in hard-to-reach tight areas
  • Will not crack or melt from the covered surface
  • Helps to prevent corrosion and keeps temperature out of the interior
  • Fast to apply
  • For better final results, it can be used in multiple layers

When you wonder if it is worth sound deadening a car using spray foam, the short answer is yes. Thanks to its elastic structure, applied spray covers vehicle elements, including the hottest areas under the bonnet.

They are best for insulating small and hard to reach places, but also to cover larger areas like car floor, or roof.

I have installed sound deadening mats in many cars. This process is always time-consuming if you want to make it right. Mats are great, for example, for covering holes in metal door panels, therefore creating acoustic boxes and help the speaker to produce better sounds.

However, the final perfect acoustic effect is difficult to achieve without finishing this job using the sound deadening spray. There is always a possibility that something will rattle in the corner.

I do not like cutting corners and using just mats for soundproofing the car, but not finishing the job with spray is like cutting corners and making it “done” quickly. 

The most significant advantage of a spray over the mats is their application speed and ease to use. Many mats are thick, heavy, and when they are not high quality, they may be difficult to cut and install properly.

is sound deadening spray good
Door interior filled with dampening spray

How does sound dampening spray work?

Sound deadening sprays are designed to create a coating on the metal surfaces, and therefore reduce the production of sound waves by vibrating car body panels. Dried sound deadening spray absorbs any generated sound waves; therefore, it makes noise to disappear.

When compared to the sound dampening mats, the spray has an advantage because it covers the entire surface and entirely blocks all sounds.

The typical spray is a liquid version of Mass Loaded Vinyl (MLV), which is a popular and effective soundproofing material, usually in the form of rolls. Thanks to sticking to the metal surfaces, sound deadening spray reduces vibrations in two ways.

  • Adding mass to the surface makes it heavier and thicker, therefore harder to move and vibrate.
  • By its finishing surface which is not smooth, it will absorb vibrations and sound waves energy before they will appear.

The sound deadening spray is generally applied to the bare metal of all the interior surfaces, the same way that mats would be. However, it is made to withstand very high temperatures and can also be used in engine compartments, as well as under the car, or as damping material covering wheel arches.

Although mats may potentially be more effective at soundproofing flat and large areas, they are more difficult to prepare and install. Because of this, it can be easier to use spray for a sound deadening car. If you still want to use mats on the flat surfaces, choosing an aerosol for the more difficult areas will be a great option to cover the whole car interior.

Which tools are needed to apply sound deadening spray?

Applying spray on the metal does not require any special tooling. Nevertheless, before spraying your vehicle, make sure you have the basics covered, especially when you are applying spray from the bulk pack that requires a spraying gun.

  • Use gloves to avoid skin contact with the spray. Some ingredients can be hard to clean, particularly these non-water-soluble, so it is good not to create a mess on the hands.
  • When you apply spray inside the garage, it is worth to wear a mask. Also, some sprays spread small particles all over the place, so it is worth filter them out.
  • To cover any areas that will not be sprayed, you have to use masking tape in the same way as when painting a car. When you do not want to clean the painted interior or windows after spraying, cover with cardboard or foil all surfaces that will not be sprayed.
  • Depending on the product type used, you may need a spraying gun and compressor. This is especially useful to cover large surfaces or multilayers. Before buying sound deadening spray, check how it should be applied.
  • For spray purchased in the bucket, you have to ensure its consistency is even before starting applying it. It is worth to mix the sound deadening fluid before using it and achieve the same effect as when shaking spray in an aerosol can. The simplest way to start mixing the liquid is to use a drill with a paint mixer. You can try mixing it without a drill, but using a drill will speed it up.

How to sound deaden car with spray?

Before deciding which product will suit your needs, you need to know how to apply it to avoid further problems. Various products may have different instructions, so it is crucial to check and compare different products.

Many of the sprays used at home come in aerosol cans that need to be shaken up well before applying the coat. Although you may need more than one can to cover the entire surface, sound deadening aerosol makes the whole soundproofing car process very simple.

To make soundproofing your car with spray easy, you have to understand all steps needed to be taken.

Below a few most important points to follow, which will help you avoid any problems down the line.

Prepare the sound deadening spray

Regardless of the type of spray you use, the material has to be prepared. This step, however, is different for aerosol spray and different for liquid in bulk pack.

– Aerosol before use should be shaken continuously according to the instruction in the room temperature.

– Sprays in gallons have to be well mixed, ensuring the same liquid consistency. Use drill and paint mixer, and mix the product for around a minute.

Prepare the surface for sound deadening

Like the sound deadening mats, the spray also has to be applied to the bare metal surface that is clean and free of rust or other dust. To clean the rusty surface, use a sandpaper or steel brush before final wiping with rubbing alcohol.

All surfaces for the sound deadening have to be clean and free of the dust. Thoroughly cleaned areas will make soundproofing effective that will last a long time.

To cover with spray only the area you want, use tape and newspaper to cover other parts of the surfaces. That will save cleaning time after spraying, especially when using products that may be difficult to remove after applying to the metal.

I am always covering everything around the surface planned for soundproofing. That saves a lot of time afterward, and it does not matter whether you sound deaden metal under the hood, on the roof, or in the trunk.

Applying sound deadening spray to the car body

The simplest way to apply sound deadening spray is to use a readymade product in an aerosol. This type of spray you can use right away after shaking it.

  • Hold the can between 8″ and 20″ from the covered surface, depending on how much surface you will cover, and how thick it will be.
  • Press the spray button down and apply it by short steady movements. Every few completed lines shake the can, to keep the spray well mixed to avoid clumps.
  • After covering the whole surface, wait the time required before applying the second layer. Do not make a layer that is too thick or when the previous one has not dried. The maximum thickness of the single-layer should be around 0.08″ (2mm), always follow to instruction, because every type of the product can have different material characteristics and can react differently to the same method.

Cleaning the equipment after sound deadening

Once you have finished applying the spray, you’ll need to clean everything down. If the product used is water-based, soap and water will be enough to do the cleaning. For other types of sprays, you can use rubbing alcohol, or paint thinner.

When you are using a spray gun, wash it immediately once you have finished, before it dries inside. Remember, this is not a thin paint that you can remove easily from inside.

Assemble car interior back together

As soon as the sound deadening spray dries completely, you can start putting everything in its place. Assemble all interior panels in the reverse order to how did you remove them and make sure not to damage any surfaces covered with sound-deadening spray.

After placing all parts back to the car, you should notice a huge difference right after the engine’s first start.

I remember when decades ago, I was driving my car first time right after sound deadening. This was an amazing but bit scary experience.

Because I used to drive and change gears (yes, I love manual transmission), by listening to the engine noise rather than looking at the speedometer, I drove much faster than usual, and the car was still silent. Likely nothing happened, but the noise reduction I achieved was outstanding.

What are the benefits of using sound dampening spray for car audio?

When you wonder if there are any benefits of using a sound deadening spray for cars, you do not have to think twice to answer yes.

  • Sound dampening spray used in the car audio is the best way to remove any noise coming to the car through the places that are too small for sound deadening mats, like inside the door, roof panels, or trunk lid. Soundproofing spray will access the most hidden corners in the car body panels.
  • The spray is a lightweight, therefore perfect solution in all places where you do not want to add too much weight, such as door panels.
  • Unlike sound deadening mats that cannot be used to cover corners and uneven edges, spray can be applied to any surface shape.
  • Using sound dampening sprays save time. You do not have to spend hours measuring, cutting, and pre-positioning anything before application, like in case of butyl mats.
  • Sprays are more cost-efficient in comparison to mats. You do not have to cut the needed shape and throw away the rest of the material. Everything that is inside the can will end up on the car body.
  • In addition to the soundproof, sprays can protect the car from heat, rust, or salt. A spray can be applied on the outside panels, underneath the vehicle, and inside the wheel arches.
  • If you are unhappy with one layer result, you can add second or more to improve the sound deadening effect in the car.

How to choose sound deadening spray foam for cars?

When preparing a car for a high-quality car audio system, it is worth to search for a low-density sound deadening spray. This type of material will maximize sound absorption inside the vehicle and will create a fantastic environment for hi-end sounds from the speakers.

Check also other properties of the sound deadening spray. Noteworthy is the ability to protect the vehicle from the heat coming from outside, which is especially important in hotter regions with little or no clouds. Driving a car that is cool inside is much more comfortable, and it does not overstretch the AC unit.

It can be handy to search for material that is flexible to use with various types of surfaces. With such kind of spray, you can cover not only interior of the car, but also exterior, or already installed sound deadening mats. These are usually high-quality materials, therefore expensive, but you buy once, and this investment in the sound dampening spray will pay back over a long time.


When thinking about improving car audio quality, not many changes can compete with sound deadening car interior. We all want to listen to the music in a nice quiet cabin while driving, and achieving this does not have to be complicated.

While sound deadening mats can be expensive and tricky to install, using spray happens to be a fantastic car audio sound deadening alternative that not everyone is aware of.

When looking for a solution to make a car quiet inside, it is worth considering sound deadening spray that is easier to apply than sound deadening mats. Sprays can work together with the mats and fill the gaps left by other soundproofing materials.

Sound deadening quality of the sprays is comparable with the mats, especially when we spray the surfaces with more than one layer. The sound deadening spray has a consistency like the mass loaded vinyl sheets. Therefore it is not only soundproof but also heat resistant.

Sound deadening sprays are a fantastic solution to absorb sound waves making them disappear and reduce door vibrations, especially in areas of connection metal panels with plastic interior. Sound deadening sprays significantly reduce vibrations transferred from the speakers to the car interior and should found its place in every car on the road.