Adding mass is one of the most important things when it comes to soundproofing, as it can block sound vibrations very effectively. In fact, when it comes down to seriously soundproofing a room, adding mass to the walls, doors, windows, etc becomes a must.
To this end, here are a couple of materials that are great barriers for sound:
#1 Mass Loaded Vinyl(MLV)
MLV is one product that is heavily used for soundproofing, and it’s probably the most popular also.
The biggest reason?
I’d say it has to do with the fact that it is extremely dense and at the same time, is very thin, and doesn’t add to the wall thickness by much.
This is a huge thing because a big issue with soundproofing a wall, say, is that as you add mass- an extra layer of drywall, or some insulation, you’ll have to give up a bit of floor space around the walls.
To give you an idea- MLV usually comes in two types- ¼” and ⅛”. The ¼” category has a standalone STC rating of 32 and the ⅛” has a STC rating of 26.
Don’t know what STC means? Read this article first. Go on, I’ll wait here!
Another great thing about MLV is that it is supple. More flexibility means that it performs even better at stopping sound vibrations
Drywall or as it’s known in the US through a popular brand name- Sheetrock- is again, one of the top materials for soundproofing.
The reason is simple:
Most US homes already have a layer of drywall. Adding another layer on top of that is simple to do and provides some real soundproofing benefits.
And it doesn’t just have to be a brute force tactic of installing another layer of wall on top of another, and hoping that their combined mass brings a reduction in noise transmission.
There are a couple more sophisticated techniques you could apply, such as:
- Staggered stud construction
- Adding a resilient channel
- Adding sound clips
- Adding a damping compound in between the drywall layers
- Adding insulation between the layers
Sounds like a lot of options, doesn’t it? Don’t worry, I’ll cover all of them in this post
#3 Floor Underlayment
If you live in a house with multiple floors, you really don’t want to be woken up in the middle of the night when someone needs to use the upstairs bathroom.
If the flooring on the upper floor isn’t properly reinforced, there is a very big chance you’ll be hearing every footstep, down on the ground floor.
This is why, most soundproofing contractors you speak to will recommend reinforcing your flooring with underlayment.
That’s another way of saying add mass to the floor. The material could be anything, really. In fact, this is another really popular use for MLV
#4 Floating floor
This is basically a new layer of flooring that goes on top of the underlayment(see point #5). Floating floors are useful because they are placed together like the pieces of a jigsaw puzzle and aren’t hard-glued together like your standard flooring.
Makes them eco-friendly too as they don’t require as much of the VOC laden glues and resins.
#5 Soundproof Glass
If the majority of the unwanted sounds are coming in through your window, it makes sense to actually devote your efforts into soundproofing it first.
The quick fixes are many. For instance, you could go around the edges, and seal any cracks with caulk/acoustic tape. This will only cost you about 20$ and 30 minutes of your time.
The REAL solution, though, will be expensive, and will put you back by about 1000$. Yes, I am talking about adding a layer of soundproof glass on your window.
One quick suggestion here- try out sealing the cracks and leaks around the window sill first and see if the amount of noise reduction you get is worth it. You may just find out you don’t need to invest a 1000$ extra.
#6 Oriented Strand Board(OSB)
A comparable material to drywall in terms of mass and soundproofing benefits, OSB, is a pretty great product.
It is made from large, cross oriented wooden strips and is generally considered a stronger material than your standard plywood.
Read more about it in this comparison post I wrote on drywall, plywood, MDF and OSB
There are some materials that act as great insulators of sound, as well as being great insulators of heat as well.
#7 Mineral Wool
Mineral wool is a material that is heavily used as an environmentally responsible means of providing noise and thermal insulation in buildings. In fact, it is extremely popular in Europe, where efforts to combat climate change are more prevalent.
According to the European Insulation Manufacturers’ Association(EURIMA), mineral wool is mostly made of industrial slag(waste material) that gets spun into fibrous threads that have unique insulating properties.
A popular mineral wool brand in the US that you might’ve heard is Roxul.
#8 Cotton Batts
A recycled insulation material- usually from post consumer use- cotton batts are slowly being used more and more these days, like this product on Amazon.
A big drawback with these is that they don’t tend to come in the exact sizes as advertised. If you try to compress them, they lose some of the insulating effectiveness.
However, they are much easier to handle than fiberglass or cellulose.
#9 Blown Cellulose Insulation
Another great insulating medium, blown cellulose insulation is made from shredded paper, that is simply slapped between two layers of walls as a noise barrier.
It’s pretty eco-friendly as well, as most times, your contractor will take a bunch of old newspapers you might have lying around the house and shred them in order to create the insulation.
It’s not recommended you make this a DIY project as there is a real chance of inhaling the harmful dust that gets created while applying insulation.
Fiberglass is essentially made by melting sand and glass together and spinning it into interlocked threads.
Fiberglass has a lot of tiny air pockets inside it which, first of all makes it a great thermal insulator. At the same time, it also is a great sound insulator.
Again, Fiberglass insulation is best left to pros as incorrect handling can be really bad for the skin, eyes and lungs(small fibers break loose when handling and can be inhaled).
Decoupling means mechanically isolating two sides of a wall in order to not allow sound to transmit from physical vibrations. Here area couple of ways that is done:
#11 Wooden Studs
While I talked about adding an extra layer of drywall to your existing wall, earlier, I also mentioned that studs can be used to make the soundproofing benefits even more enhanced.
Wooden studs are basically a couple of wooden logs that are long enough to cover the height of the wall. After placing the stud on the first drywall layer, you’ll apply the second layer of drywall on the other side of the stud instead of directly on the first layer of drywall, which leaves a small air gap in between them.
When correctly done, the air gaps become insulating rather than conducting for sounds and the studs stop mechanical transmission of sound through the layers.
#12 Resilient Channel
A resilient channel is basically another isolation method. It’s like a metallic bar that runs the length of the wall and is placed on between the studwork and drywall layers to isolate things even further.
Now, this is a topic in itself, so I wrote a complete on resilient channels, if you’d like to know more.
#13 Sound Clips
Quite similar to a resilient channel, a sound clip will usually have a rubber dampener base to stop sound vibrations further. They are generally regarded as better performing than resilient channel.
These products literally do what their name suggests- dampen the noise vibration. Standalone, a damping compound may not be as effective, however, when combined with other soundproofing methods, such as adding mass, it provides even better results.
What it basically does is, it resists the force of vibration that sound exhibits on a medium. The vibration energy, instead, gets dissipated in the form of heat, at a molecular level.
Another thing to note about damping compounds is that they don’t give immediate results. It usually takes about 90 days for the compound to be fully set and start providing effective sound reduction.
If you live in a cold climate, this period could well be extended by another few weeks, so you should keep that in mind.
Also, like I said earlier- damping compounds are meant to be used in conjunction with other soundproofing materials, and not as the most important method of soundproofing.
I suggest you get a professional opinion first, even if you plan on doing the soundproofing yourself. Otherwise, you may just realize later that you needed to add more mass or decouple the walls to get the kind of sound reduction you were looking for and be disappointed.
#14 Green Glue
The most popular noise dampening compound on the market today. I wrote a whole article on it. Check it out here
#15 Quiet Glue
The only other competitor to Green Glue in the market, Quiet Glue has quietly made a name for itself(sorry for that pun, I just had to)
While it is a slightly cheaper product, there are a few drawbacks with Quietglue:
- Doesn’t seem to be as efficient at noise dampening as Green Glue
- Beginners usually find it tougher to use than Green Glue
- Takes a longer time to set
For Plugging The Gaps
You could’ve gone ballistic with your soundproofing efforts and redone the windows, walls, doors- only to still have sound leaking through a few areas.
That’s why soundproofing should be a holistic exercise, with you taking every aspect of a room and it’s surroundings into account before doing anything.
That being said, here are a few places where sound can leak through and what you can do about them:
#16 Door Sweep
You may have the sturdiest door but if there’s a small gap underneath it where sound can escape from- be assured you WILL get noise.
Which is why I recommend this simple to apply and inexpensive door sweep as something you should consider getting as a first step before soundproofing your door.
Use it for a day or so and see if the sound levels get lowered to any significant extent.
Caulk is great for filling in cracks- which usually form at the corners of a room. Places such as your window sills, around the door frame edges, etc.
All in all- another space where sound may leak through into your room.
#18 Acoustic Putty
Adding an extra layer of drywall or MLV is tricky around the electrical outlets. You have to make sure you don’t accidentally cover the wirings with insulation, as well as not to block the outlet itself.
This involves cutting the material around the electrical outlet so as to avoid it. If not done properly(which can be quite tough), you may end up with a gap around the outlet where noise leaks through.
Which is why, the best practice, really, is to wrap an acoustic putty around the outlet before that layer of drywall or insulation is applied to the wall. This protects the wirings, as well as ensures that the insulation settles around the outlet in a uniform manner.
For Improving Room Acoustics: Absorption Compounds
These aren’t technically soundproofing materials- rather materials that improve room acoustics. However, a lot of people tend to mix up the two of them, which is why I decided to include both of them in this article.
Just to be clear, the products listed below will improve the acoustics of the room you are in, i.e: decrease the amount of echo or reverb you hear. They will definitely NOT block noise from coming into the room/ going out.
Typical use cases for these materials are for building a home recording studio, music room or home theatre.
#19 Acoustic Foam
These are good for stopping mid to high range frequencies(150 Hz+) but not really good enough for bass frequencies.
Acoustic foam comes in many styles- such as egg crate, wedged, smooth- and is widely used in improving room acoustics.
Go to any professional studio and you’ll see all the walls completely covered with acoustic foam.
While that’s an expensive proposition for almost anyone who isn’t a pro, it doesn’t mean you can’t use acoustic foam. About 25% wall coverage will give you good results. This comes to about 150-200$ in expenses, for the average room.
If you’d like to know my top picks for acoustic foam, as well as exact directions on where and how to apply them, the results you can expect- go here.
Resonating bass traps
These are professional solutions, and probably overkill for home usage. However, when it comes to a REAL solution for eliminating low frequencies, resonating bass traps are it.
#20 Helmholtz Resonators
Like the name suggests, these products stop the propagation of bass frequencies inside a room- which can be terribly hard to do.
A helmholtz resonator consists of air tight cavities that have ports to let in bass frequencies from outside. It needs to be tuned to a particular frequency in order to absorb it, which is why it’s the most effective solution.
A professional will calculate and give a recommendation for the frequency it should be tuned at in order to remove the most pervasive low frequencies- which can be different for every room.
#21 Diaphragmatic Bass Traps
A diaphragmatic bass trap will absorb bass frequencies that crash against the membrane. Unlike the Helmholtz resonator, it doesn’t really need to be tuned to a particular frequency, and it absorbs a range of lower frequencies.
All in all, a bit more user friendly.
#22 Foam bass traps
Foam bass traps are something that people at home can think of buying. They’re made of open cell foam, fiberglass type materials that are good at absorbing lower frequencies in the 100 Hz to 150 Hz range.
I know, it’s not really a bass trap if it only works for for above ~100 Hz frequencies. If you have medium expectations though, these will work just fine for you. Read this post about foam bass traps to know more.
#23 Soundproof Curtains
They perform reasonably well at blocking outside sounds, and also double up as insulators that will keep away the heat in summers and keep the cold out in winters.
Soundproof curtains are really heavy because of the material used and the way they’re woven. This is why most of these are also marketed as blackout curtains.
Here are my recommendations on the best soundproof curtains and how you can use them well.
If you don’t have the extra cash though, you don’t really have to spend 150-200$ on a pair of curtains. As an alternative, a pair of thick moving blankets can also be used as curtains.
You’ll have to be a bit creative with figuring out how to hang them, and granted, they may not look amazing- but they’ll get the job done just as well.
#24 Soundproof Paint
Last and DEFINITELY the LEAST, comes the matter of soundproof paint.
What can I say, there actually are pages on the internet trying to convince people that a layer of paint can have soundproofing benefits.
Let’s go back to the principles of soundproofing. To be an effective soundproofing medium, it needs to:
- Have a lot of mass OR
- Dampen the vibrations like green glue OR
- Decouple the structure(i.e: isolate each layer of the structure you’re soundproofing)
A layer of paint does none of these.
Enough said now- just please do not waste your money on these products.