How Does SOUNDPROOFING Work? The Science Behind It

Though there are many beautiful sounds you can hear throughout the day, there’s also unwanted noise. Different sounds can be especially annoying when they appear at the wrong time when you’re trying to sleep, study, or talk on the phone.

If there’s an issue with some kind of noise, the best thing to do is try to kill it at its source. Try to identify the sound and where it’s coming from. If the problem is in another room of your house, the solution is simple.

However, you might need a different approach if the sound is not coming from your house. If you live near a bar, or your neighbor has a recording studio, it might be impossible to get rid of the noise. In this case, you’ll have to convince your neighbor to soundproof its house, or you’ll have to adjust yours.

If you’re a musician or a DJ, you can easily be a noisy problem to someone else. Maybe your washing machine is disturbing the neighbors below, and they complain every time you’re doing laundry. Whatever the case may be, it’s best you consider a method of soundproofing to prevent the noise from bothering you or your neighbors.

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What exactly is soundproofing?

Absorbing and reducing the noise and preventing the sound from traveling are what we consider soundproofing. It also doesn’t matter whether you’re trying to stop the sound from leaving or entering your room.

Have you ever seen those foamy walls in a recording studio? Well, that’s soundproofing at its most common use. Soundproofing has its professional use as it’s often found in recording studios and offices. However, nowadays more and more residential buildings, apartments, and houses also turn to it, especially if there are shared walls.

How does soundproofing work?

The first thing you should know is that there are two different types of noise. The airborne noise is the one we come across the most often, and it’s the one that travels through the air. It’s usually talking, loud TV noise, music, etc. Impact sound is a common issue as well, and it’s usually a problem in apartment buildings where you can hear the neighbors above you when they walk, run, or drop something on the floor.

There are three ways in which you can soundproof your room. One of them is to block the sounds by adding more mass to your walls, so the noise is reduced or converted into heat. Another thing you can do is stop the noise from traveling from one structure to another. The third method is called sound absorption which is essentially adding a material that absorbs the noise and reduces it.

However, regardless of the method you opt for, you have to do it the right way. If you leave the smallest gap, the sound will travel through it, and it will be as if you’ve done no soundproofing at all.

Why should you soundproof your room?

Soundproofing isn’t something you have to do so it’s up to you to decide if you need to. If your house/apartment has thin walls, floors, and ceilings, it’s likely that you can hear lots of different noise throughout the day.

Older houses usually have quite thick walls, so they don’t require soundproofing as much as recently built houses. However, mass is the main thing that protects your indoors from outdoors noises, so it’s about adding as much to your existing walls.

Even some every day sounds like TV, music, washing machines, and heating pumps could be an issue in which case you should consider some type of soundproofing.

Though soundproofing won’t increase the general value of your property, it’s a bonus for when you’re trying to sell it. Most building owners nowadays try to improve sound insulation in shared properties such as hotel rooms and apartments.

Still, no law requires you to soundproof or not. If you’re making noise, you’ll have to turn it down, but you don’t have to soundproof your house. It’s a matter of your choice.

Types of soundproofing

There’s a difference between whether you want to absorb the noise within the room or reduce and prevent it from entering the room. Though they seem the same, they offer different solutions. For best results, it’s recommended you apply them in combination.

Doing just one of these is still effective, but the results won’t be nearly as impressive as when you combine all the elements of soundproofing.

There’s reducing, absorbing and decoupling. These are the three elements of soundproofing that offer the best results when you apply them all.

1: Reducing

Reducing sound means minimizing and preventing it from leaving or entering the room. This is usually done with insulation materials that act as barriers that prevent noise from traveling to another room.

Room dividers, temporary walls, curtains, and foam are the most commonly used materials that reduce sound. Most are made of fiberglass and wood though there are other choices, too. Creating an airtight barrier is also an effective method to reduce noise, but this is a bit tricky to do since you can’t breathe in a completely airtight room.

The most popular method of sound reducing is building two doors or walls with air in between. Two walls or doors block the sound while the air in between helps furthermore.

The key is to block the path sound can take into the room. Heat insulation can help at times, but the effect won’t be the same as if you were to use actual soundproofing materials.

2: Absorbing

Reducing noise is an excellent method though it does leave an issue behind. Once you install thick walls and doors, the sound will bounce off them creating an echo effect. So, you need a softer material to absorb the sound that’s already in the room.

The most commonly used material is dense foam though you can find several others that work just as fine. Because these materials are soft, they absorb and reduce the noise. This is something you can do either inside or outside of a wall. Sound absorption materials are close to useless for soundproofing on its own as they should be used in combination with actual soundproofing materials.

3: Decoupling

Acoustic decoupling is usually also called a “room within a room.” The two rooms are built from solid and heavy materials, but they cannot be touching one another. If they do touch, the sound will travel right through. Since sound is a vibration, it goes when there’s a clear and direct pathway.

This is why you build a smaller room inside a larger one with some space between them. In most cases, the inner room is supported by small clips, and you’re supposed to line the walls with appropriate materials that have sound-absorbing qualities.

How to block out sound

Soundproofing is essentially just blocking sound to go out or get in. It can be done in three ways that provide somewhat the same results but are different in terms of simplicity. You can use space, mass and dampening to reduce or block pretty much any noise.

  • Space – this is simple to understand since we come across the example in everyday life. If there’s a noisy bar down your street, you probably cannot hear it since it’s so far away. There’s too much space between so the noise simply can’t reach you.
  • Mass – this is also nothing complicated as mass can help lower the noises. The more mass between what’s making the noise and your room; the less noise you’ll hear. The clearest example is when you simply close the door of your laundry room to lower the noise the washing machine is making.
  • Dampening – this may not be as simple, but it’s effective. We’re talking about forcing the sound waves to go through lots of layers absorbing it along the way. You dampen the sound and its ability to vibrate which is one of the most effective ways to soundproof a room.

What can you soundproof?

In most cases, every room or area of it can be soundproofed one way or another. You can soundproof your entire house as you build it or just a few rooms.

Sound travels through even the smallest gaps, so windows, doors, floor, and walls are almost no barrier at all. Stop and listen before you do anything. Identify where the noise is coming from and how it’s entering your room. Inspect all walls and doors to see if there are any gaps where the sound is getting in and out.

The great thing is that you can soundproof just about any part of your house. If you choose to do so only with windows, you can. It’s also possible to soundproof just doors or a specific wall.

If you live in an apartment building, you can do many things to soundproof your ceiling in order to reduce the noise from above. The same goes for your floor. If you feel like you’re the noisy neighbor, you can add mass to your floor, so you don’t disturb other tenants.


Is soundproofing something I can do alone?

There are countless ways and methods in which you can improve the ability of your room to block or absorb the noise. The choice of materials is also quite vast so that you can choose according to your budget and skills.

Some larger projects like adding concrete to your walls might require hiring a contractor. However, other projects are simpler for you to do them yourself. Soundproofing doors and windows are quite easy, too.

Soundproof vs. sound absorbing materials

Since sound absorption is an element of soundproofing, it shouldn’t be considered the same. Materials used for soundproofing prevent the noise from going out or in your room. On another hand, materials we use for absorbing are those that improve the acoustics.

If you just use sound absorbing materials, you’ll do very little in terms of actual soundproofing. You want to combine the two to get the best results.

What are the most common materials used for soundproofing?

As we’ve mentioned, the market is packed with different materials that vary in thickness, texture, and ease of use. One of the most popular choices is mass-loaded vinyl. Green Glue is also a practical option, and it’s quite affordable. Soundproof foam panels and curtains are often found in recording and rehearsing studios. For domestic use, door sweeps and seals are a great way to soundproof.

Does insulation help with soundproofing?

Heat insulation can’t help a lot, but soundproofing insulation can. If it’s made of fiberglass, cellulose or foam, it will be able to protect you from outside noises. These can be installed in floors, ceilings, and walls.

Can you soundproof an existing wall?

Yes, and in many ways. There are many methods in which you can improve the soundproof qualities of an existing wall without hiring a contractor.

Simple things like Green Glue and mass-loaded vinyl can help and aren’t so complicated to apply. Even adding foam panels or soundproof paint is a good way to block the sound from entering or leaving the room. In most cases, even the smallest effort will pay off since you just need to soften the surface a little or add mass to it.

What is the cheapest way to soundproof?

Soundproofing can cost up to hundreds of dollars for simple pieces of foam, so it’s a good thing to consider less costly alternatives.

If you’re on a budget, make sure all your doors are sealed. It’s also essential to install a door sweep that’s a cheap and simple solution for stopping the sound. An acoustic sealant can help prevent noise from escaping through crevices.

Another thing you can do is hang heavy curtains over your windows. An even cheaper option is to hang thick blankets.

Don’t forget to soundproof the floor, too. Concrete or hardwood floors are the worst when it comes to echo, and sound travel so make sure to add something that would dampen the surface. Just adding a thick rug will do wonders in terms of preventing the noise from bouncing around the room.