Carpeting your walls doesn't help soundproof them, yet it can help improve the acoustics of a room if done correctly.
Ideally, carpet should be hung around 125mm away from a wall instead of secured directly to it, this will create an air trap which will help deaden sound.
Sticking carpet directly to a wall will have no impact from a soundproofing perspective.
In terms of the acoustics of a room, it will deaden high-frequency sounds but will have no impact on mid-low frequency sounds, making the acoustics sound dull.
Before we dive into the details of wall carpeting it's important to clarify exactly what soundproofing is.
Confusing soundproofing and sound dampening is an easy mistake to make.
If you want to completely block sound from traveling through a wall then you need to soundproof it.
If you want to improve the acoustic of a room and reduce echo then you need to dampen the sound by absorbing it.
Putting up a few foam panels on your wall will do nothing to stop sound traveling through the wall however it will make the sound inside the room sound less echoey and therefore better if you are recording a YouTube video or podcast.
In short, not really.
Carpet isn't designed to block sound.
Mass, such as a wall, blocks sound.
Carpets have very little mass and are not very dense or thick so are therefore not great at soundproofing.
That said, soundproof carpets or acoustic carpets do exist (though the name is a bit of an overstatement).
They are designed to reduce the amount of impact sound that travels through the floor - ideal for apartment living.
They do this by being soft and spongey so that when something hard or a heavy foot impacts the floor the blow is softened which reduces the amount of sound energy that travels through the floor into the room below.
The thicker the carpet the more softened the impact will be and the less noise will be produced, for example a deep pile carpet will do a much better job of dampening impact sound.
A floor's main soundproofing problem is with impact sound (vibrations traveling through them), they deal with airborne sound quite well as they are usually dense enough to block it, especially if the floor is concrete.
Carpet is not thick enough to have a big sound dampening impact when you hang it on a wall.
It will only dampen high-frequency noise and make no difference at all to medium and low-frequency noises such as bass.
If you are using the room as a recording studio or music room then this can distort the sound, making music sound very dull.
If you've got your heart set on soundproofing a room with carpet don't worry all is not yet lost because there are a few tricks you can use to make it work.
If you can find carpet which is rubber backed this can make a big difference.
Rubber backed carpet should be airtight (providing it is not damaged) so can be used to create a seal.
If you can hang the carpet around 125-170mm away from the wall and find a way of sealing it around the edges then it can make a big difference to sound transfer in and out of the room.
If you want to soundproof an entire wall using carpet then we recommend you make a stud frame which fits the room and secure the carpet to the frame ensuring that all the edges are fully sealed up with a combination of rubber carpet and green glue so that air (and more importantly sound) cannot pass through.
This works because the rubber backed carpet creates a dead air space between the wall and the carpet which seals the sound in.
If you are more concerned about improving the acoustics of a room you can also use rubber backed carpet to seal off corners of the room like a D.I.Y bass trap, this will help dampen lower frequency noise though it won't do much to soundproof the room besides reducing bass reverberation.
Another thing you can do with rubber backed carpet to reduce echo is hang strips of it around the room near the walls, roughly 100-150mm away from the wall.
As sound waves bounce off the wall they will hit the rubber carpet which will absorb and dampen much of the sound energy, the overall acoustical impact is similar to the effect of sticking purpose made acoustic panels on your wall...just cheaper!
Unfortunately not only does carpet not work well for soundproofing walls but it makes your room look awful!
It is only really good as a short term solution when you have no other options available.
Of course, the best option will always be to properly soundproof the wall however there are plenty of alternative cheap (carpet-free) ways to soundproof a room, if time and budget constraints are issues.
Here are a few you could try instead:
Mass blocks mass, windows are therefore a weak point in most walls as they contain far less mass than a wall does.
If your window is single-glazed you will definitely notice noise easily passing through it.
Creating a window blocker will make a much bigger difference to how soundproof the room is than carpeting the walls will.
With a small window, blockers can be made from sofar cushion which can be squeezed to fit inside the window frame.
For bigger windows, a more effective long term solution is a custom-made soundproof window plug designed to precisely fit the window.
You will need to make a wooden frame that fits your window, mount the frame on a hardwood board and then use green glue to seal a thick soundproof mat to the window side of the board.
These are excellent at dampening vibrations and providing it fits the window frame well also makes a big difference to airborne noise too.
If you have a problem wall which you need to soundproof sometimes the problem can be fixed simply by moving the correct furniture in front of it.
Big floor to ceiling bookcases are ideal because they add a huge amount of mass to the wall (unlike carpet) if they are filled up with books which does a great job of blocking sound from traveling through the wall.
Weather stripping is one of our favorite soundproofing materials here at Soundproof Panda.
It is very cheap, very easy to use and very effective.
It one of the first things I do in any room that has soundproofing problems.
Often sound travels under doors and through gaps around the door frame, the same is also true of older windows which may be poorly fitted or have warped frames.
Fitting weather stripping inside the door frame seals up gaps and makes it far harder for airborne sound to travel through the door.
If you combine weather stripping with a door sweep (to completely close off the gap beneath the door) and even consider swapping the door for a more dense hardwood door then you may find that all your soundproofing problems are resolved already, without any need to hang ugly carpet up!
You see them in the background of many a YouTube video.
Acoustic panels do what rubber backed carpet hung close to the wall does...but they don't look anywhere near as ugly and they are purpose made for it so they are more effective.
They are designed to reduce reveberation and echo in an enclosed space which is why you see them in recording studios.
They are very simple to install, panels can be hung up much like a picture, if you opt for hte foam squares these commonly have a sticky back on them allowing you to peel them and stick them to the wall.
These have a similar impact to acoustic panels, the sound deadening layered fabric of a thick soundproof curtain helps reduce reverberation and echo thus improving the quality of audio in a room.
They look far nicer than carpet and can be more effective too, especially if you get a floor to ceiling style curtain.