Why Is It Good to Sound Deaden a Car?


When upgrading a car audio system, we often have to make other changes in our vehicles, but why should we sound deaden a car?

Sound deadening car interior significantly increases the driving comfort, especially when driving at high speeds on highways, when the noise gets inside the car from the wind, tires, engine, and all around. Having a vehicle that is silent inside makes driving more comfortable for children and animals.

It is also an excellent solution for audiophiles because even the best and most expensive audio system will not play well in a loud car. In a well-soundproofed cabin, you can also make phone calls or having a conversation without shouting over each other.

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If you would like to go through more details about sound-deadening cars, the article below will show you the benefits of soundproofing the car, what to focus on, and how to choose the right sound-deadening materials.

Where is the noise inside the cabin coming from?

sound deadening car door

The noise level inside of the car primarily depends on the driving speed.

  • When driving slowly in the city at around 30mph, most of the noise we hear comes from the engine.
  • At speed between 30mph and 50mph, the most audible are tires rolling on the tarmac
  • Above 50mph, and during monotonous driving on the highway, most of the noise is caused by airflow around the car.

In the case of tires, the cheap all-season and winter tires make most of the noise because of their material composition. In many cars, the quality of factory-fitted tires is mediocre, so they do not offer either comfortable driving or low noise.

Thus, we often replace factory tires with better quality aftermarket tires that make much less noise inside the car.

Engines are also troublemakers. Although most modern engines are quiet, they do not stay brand new forever, and with a car’s age and increased mileage, they get louder. Components inside the engines like shafts or bearings wear out and become loose. It also does not help when we skip regular services or oil changes.

Also, door seals that wear and become harder over time, cause excessive noise of the airflow around the car’s shape. There are ways to soften the door and windows seals, and by doing so regularly, we not only increase their lifetime but also make them to better form against the metal door and, in effect, we keep the wind out of the cabin.

To all of these noises that our cars make, we have to add sounds that we rather do not listen to with pleasure, like the other car engines, especially these with damaged or tuned exhaust, bikes, music all around, etc.

People usually do not realize how all these noises affect our nervous system (article opens in the new window). A busy street can generate noise of 100 dBA or more, while the safe noise level for human ears is 85 dBA (article about various noise levels opens in the new window).

It is a sizeable difference in the noise between various car types. While luxury cars create below 60 dBA inside the cabin, in small sports cars, we can experience over 70 dBA, because of less sound-deadening materials installed due to the weight reduction, or less resistant mufflers to increase performance, etc.

One can tell it is just 10 dBA, so not much. Well, not exactly. In reality, 70dBA is over three times louder than 60dBA, because the sound is measured in the logarithmic scale, which means that with every 3 dBA increase, the noise is twice as loud.

How sound deadening affects music quality?

There are not many more annoying sounds we can hear, than rattling or squicking door right after installing brand new speakers. When we spend thousands of dollars on the quality car audio, including powerful door speakers and amplifiers, we should not save on sound deadening the car. Especially soundproofing doors should be part of every car audio improvement.

In a soundproofed car, you can listen to music like the inside of the acoustic studio. In other words, you can start hearing how speakers actually perform, and the difference is huge. You do not hear any more plastic resonance, distortion, or interior vibrations.

Even average quality soundproofing materials can make a noticeable difference. Is it, therefore, recommended to add sound deadening mats and foams to the door at the same time when you replace the speakers.

I could not believe when listened to the music the first time after I made from doors proper enclosures thanks to butyl mats and foams. Sounds became much more dynamic and precise. The difference is especially noticeable in mid-bass.

To imagine the difference, try to listen to the music from the speaker lying on the table, and then take the same speaker and install it into the enclosure. The similar effect you will see in the car before and after sound deadening.

Although there are more cars on the roads with a completely soundproofed interior, the most critical areas for the music quality are the doors or side interior panels in the back of the two-door vehicles.

In general, every piece of a car interior to which we connect speakers should be covered with sound deadening panels and foams. Even if you have a tight budget and do not want to soundproof the entire car, adding mats to the door will provide you with much better acoustic experience, than mounting speakers in a raw sheet metal enclosure.

The final effect will be actually much better than adding an amplifier to the same speakers but without sound deadening the door.

Why is it worth to sound deaden the car?

Although the sound deadening car interior will improve music experience, this is not the only reason why we should go ahead and add rubber panels to our cars.

With each year, more drivers decide to soundproof their cars, and they are not all audiophiles. And this is not only for the used cars, with old engines that are louder. More and more new vehicles being soundproofed because of their mediocre factory insulation.

Sound deadening can be skipped when you drive Rolls Royce or Bentley, but unfortunately, I am not one of these happy drivers.

In addition to the sound reduction after soundproofing, we notice that the car interior is not heating up as much when it is hot outside. This is due to insulation layers that prevent heat from entering the cabin, primarily through the roof and doors.

Every person has its reasons that drive soundproofing decisions, but in general, sound deadening increases the driving comfort.

In my case, I love silence while driving. Driving a car for me is pure relaxation. I often listen to the favorite Jazz filling the entire interior from 11 speakers around but is not too loud. It is just perfect, exactly as I want it to be. This level of silence was not possible to achieve without soundproofing when I had to hear all of the wind noises mixed with high tones.

Which soundproofing materials should I use in a car?

When searching for the sound deadening, you will see a wide selection of materials with different thicknesses, shapes, and of course, different prices, but which one is the right one for your car?

First, it depends on the part of the car you want to soundproof, and whether the material must also be water or heat resistant.

For example, foam panels that work great when installed in the door will do more harm than good when placed under the hood. And vice versa, soundproofing panels with silver foil that absorb heat are not needed on the floor where is always lower temperature than on the roof.

which sound deadening materials to choose

Below are the most common material types we use in our cars:

  • The wool sheets, also known as felt mats, are the simplest and cheapest way to reduce noise in the car. They are quite thick and have excellent noise absorption. However, they quickly absorb water that can cause corrosion, besides they are heavy.

Wool pads are often used as factory soundproofing of floors and wheel arches and placed directly under the floor carpets.

  • Bitumen sound deadening pads are the other cheap option for car insulation. They are heavy and tend to crack due to their stiffness. Also, before sticking them to the metal parts, they have to be heated to become more elastic.

Bitumen panels reduce vibration and are excellent for large flat surfaces, like floor or trunks. However, they are not the best choice for the door and roofs because of the high temperatures in the summer that can cause the rubber to melt.

  • Butyl is the higher level of the sound deadening material. Butyl mats are more expensive but provide better damping noise protection than bitumen. Also, butyl can better handle extreme temperatures, which means there is no risk for the butyl panels to break or melt.

The aluminum layer that covers butyl panels makes additional heat protection in the areas with high temperatures. They are perfect for sound deadening engine areas as well as other parts of the car.

  • Sound deadening foams have an additional benefit over the rubber mats. They can reduce high-frequency noises coming, for example, from the wheels or wind. This is why they being often used on the wheel arches and as a second layer on the floor and inside of the door panels that are placed right on top of the butyl mats.

Can I sound deaden the car myself?

It is possible to soundproof the car ourselves at home, and I did it a few times. However, this is not the simplest task and may not bring any results if it is not done correctly.

First, we have to choose the right materials and quantity. Next is disassembling the entire car interior, and although it may not sound complicated, it is important not to damage anything, especially small plastic mounting clips.

Another important thing is to precisely measure and cut the sound deadening panels to make sure they match together. Do not leave any free spaces or gaps that may cause noise not to be reduced to the level we want.

The doors have two layers of metal sheets. The outer one that is painted from outside, and the inner panel, that holds all door equipment, including speakers and door handles.

sound deadened door panel

For the best results, we have to cover both door panels with soundproofing materials. The outer side of the door has to be covered with a butyl mat that is sound and vibration resistant, and the inner panel, in addition to the butyl mat should be covered with either rubber or foam panels that offer better noise protection.

Let’s look at the example of steps to be taken when a sound deadening car door:

  • Prepare the right amount of selected soundproofing materials. For example, the door needs around 9 square feet of flexible butyl panels and the same amount of the rubber or foam mat.
  • Remove the plastic door panel. t Depending on the car model, we need to loosen the screws, debond the mounting clips and properly disconnect wires to the windows and mirrors steering. In cars with manually lowered windows, we have to remove window handles.
  • Remove the interior door handles, speakers and their covers, other plastic elements, wires with their clips, and plastic or paper sheets.
  • Clean and degrease the raw metal surfaces.
  • Place prepared butyl panels inside of the door and stick to the outside door panel. This is a tricky part because we have to push the rubber through the holes (also through the speaker holes), which are small in some cars. At this point, we have to be careful and not to block any drain holes at the bottom of the door.
  • Stick prepared rubber or foam mat to the metal door panel from the cabin side. Make sure there is left room for free movement of the door handles and window mechanism.
  • Put back in places all plastic clips, connect wires and install speakers. At this point, we have to test if speakers, electric windows, and mirrors work correctly.
  • If all equipment functions correctly, we assemble the door back together. With additional layers of soundproofing mats, you may need to push plastic door panels harder, to make sure plastic clips click correctly into a metal door.

Conclusion

The noise in a car is one of the most common reasons we replace cars. Many people think that the only way to reduce noise in the vehicle is to replace it. However, the majority of new cars are also too loud, and with time, we feel that driving it is not as comfortable as we thought.

It is also worth mentioning that better sound insulation is one of the criteria distinguishing cars’ premium class.

You can reduce noise in the cabin without replacing it with a new one, and you can do it by soundproofing your car. This is a cheap and effective way thanks to which, you can increase driving comfort and start listening to the music of better quality.

Martin

Welcome to ImproveCarAudio! I am Martin, and I love to write about everything related to car sound systems. I strive to provide the most accurate and helpful information about car audio through extensive research, as well as my experience with car audio installations.

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