MLV vs. Drywall for Soundproofing
As an expert in soundproofing, I’m often asked about the benefits of MLV vs. drywall. After spending some time researching, I’ve come up with a quick answer:
The benefits of using MLV vs. drywall relate to its mass and density. MLV is great for blocking and dissipating sound waves, and its density makes it much more effective at this than drywall. In fact, it’s one of the most useful products for soundproofing a structure.
Also read: Green Glue vs. MLV
What is MLV?
MLV is short for mass loaded vinyl (Amazon link). It’s a great product for soundproofing a range of structures and was designed specifically for this task.
Importantly, it’s what’s known as limp mass. This means that when sound waves make contact with it, they’re unable to make it vibrate.
Limp mass is particularly effective for soundproofing because it physically blocks sound transmission rather than just absorbing or dampening the sound waves.
But how does it work?
MLV is made from 2 outer layers of vinyl with a core of high-density material, which is usually calcium carbonate or barium sulfate. Both of these products are dense and flexible.
MLV comes in a range of densities, from 1/2lb. per square foot to 2lbs. per square foot. Obviously the denser the material the better it is at blocking sound.
It’s known as a viscoelastic compound, which means that, although a solid, it has elastic properties. These are what provide it with the ability to block sound waves.
Viscoelasticity is very useful in soundproofing because it flows when a force makes contact with it (sound waves) but then returns to its original form once the force has been removed.
A common and useful analogy for understanding this concept is throwing a ball at a hanging bedsheet.
You throw the ball at a bed sheet hanging on a washing line, and what happens? The ball drops to the floor because the bed sheet has dissipated the energy in a 3D space.
If you throw a ball at a rigid surface, such as a wall, it’s able to bounce off again. The residual energy would cause the wall to vibrate, to an extent.
The process is exactly the same with sound waves, which are vibrational energy. They’re good at making rigid objects vibrate, but this same energy is dissipated by a flexible material, such as MLV.
What is Drywall?
It’s fair to say that most people know what drywall is, but it’s probably worth defining in the context of soundproofing.
Drywall is made from a sheet of gypsum sandwiched between 2 sheets of paper. As a construction material, it’s useful because it’s inexpensive, easy to use, and widely available.
In terms of soundproofing, it’s not great. In fact, it’s basically the wall we mentioned above: sound waves will easily bounce off it and transfer through it.
Realistically, drywall isn’t designed to be soundproof; it’s too thin and rigid.
That said, it often forms the basis of many soundproofing projects because it’s pretty easy to modify with other materials, such as mass loaded vinyl.
It’s possible to add several more layers of drywall to overcome its failings, but this really doesn’t add as much as using actual soundproofing materials.
You can buy soundproof drywall, which has an inner layer of viscoelastic material. But this is a specialty product and doesn’t really make much difference.
MLV vs. Drywall Comparison
While these products are fairly different, it’s possible to compare them in a few ways.
To make this easier, here’s a handy comparison chart.
| MLV | Drywall | |
| Material | Vinyl, viscoelastic compound | Gypsum board, paper |
| Cost | Moderate-high | Low |
| Availability | Easily available online | Available online and in-store |
| Density | 1/2-2lb per square foot | 1.6lb per square foot |
| Ease of use | Easy-moderate | Easy |
| Effective against | High and mid-range frequencies | N/A |
| STC | 30-50 | 30-34 |
Generally speaking, there aren’t any useful factors in which drywall wins. Sure, it’s more widely available and cheaper, but these aren’t really helpful if you want to soundproof a room.
That said, mass loaded vinyl can get quite expensive if you need a lot of it. It’s worth the investment though because it does a great job of blocking sound transmission.
This is evident in its STC or sound transmission class. STC is a numerical rating that states how well a material or structure isolates sound. The higher the number the better.
Depending on the thickness, drywall has a maximum STC of 34, which isn’t amazing.
MLV, on the other hand, has a maximum STC of 50, which is one of the best ratings you can get. Again, this depends on thickness and material used.
It’s also more effective against a wider range of sound frequencies, but this is because drywall isn’t designed as a soundproofing product. However, even MLV is let down at low frequencies.
To overcome this problem you’ll want to use it alongside other materials that are good against low frequencies, such as mineral wool insulation (Amazon link).
It’s also worth considering ease of use. Drywall is designed to be easy to use; you simply need to screw it to wall joists.
MLV isn’t a difficult product to use, but you’ll need to use it with something more rigid to provide stability.
It’s entirely possible to fix it straight to wall joists, but its weight and flexibility make it a bit of a challenge.
You’ll have a much easier time mounting it on a sheet of drywall, for example, and then hanging this in the normal way.
So to summarize, mass loaded vinyl is a very useful product for soundproofing and has a wide range of uses.
However, it’s worth using other products alongside that compensate for its weaknesses. A good soundproofing project will make use of materials that block, absorb, dissipate, and isolate sounds.
How to Use MLV for Soundproofing
One of the best things about mass loaded vinyl is its versatility. Here are the best ways to integrate it into a range of soundproofing projects.
In Vehicles
Not everyone wants to soundproof their car. But if you do, MLV is a good product to use.
Its flexibility is useful here because you can fit it into small gaps inside the vehicle’s cabin or wrap it around the inside of doors or the trunk.
However, if you need to soundproof the vehicle’s hood, I’d recommend using a sound deadening mat.
These are made from butyl rubber, which shares many similar properties with mass loaded vinyl. The major difference is that it has much higher heat resistance, making it suitable for putting near the engine.
Under flooring
Mass loaded vinyl can be put under flooring, both hard (such as laminate) and soft, such as carpet.
It’s not specifically designed as floor underlayment, but there’s absolutely no reason why it can’t be used for this job.
You’d simply have to put a layer down, possibly with some Green Glue (Amazon link) underneath, and then lay the flooring on top.
However, a good alternative is acoustic foam underlayment. This generally performs better because it’s designed to be effective against impact noises over airborne noises.
This is possible because it’s able to compress slightly under force. MLV doesn’t really do this; it just doesn’t vibrate.
MLV would still do a good job under flooring though, so don’t overlook it.
Ceilings
Ceiling cavities are often an issue in soundproofing projects. They’re perfect for transferring sound waves between floors, and if left hollow can help to amplify impact noises.
You can combat this by not only putting MLV under the upper floor but also on the ceiling of the lower floor.
I’d recommend assembling materials before fitting them in place though, as it can be difficult to work on ceilings with accuracy.
Simply do the following:
- Start with sheets of drywall measured and cut to size for the ceiling.
- If the cavity is empty, line it with mineral wool insulation.
- Working on the backside of the drywall, add a layer of Green Glue (2 tubes per sheet).
- Lay the mass loaded vinyl on top and fix in place with staples or tacks.
- Fix the drywall in place with the drywall facing the cavity.
And that’s all there is to it. Adding the Green Glue provides an extra level of sound dampening, as it converts sound waves to heat energy.
Similarly, the mineral wool will help to absorb and muffle some of the noise coming from the floor above.
Soundproofing walls
To soundproof walls, you’d pretty much follow the same method as for ceilings.
However, it’s possible to make your own acoustic panels for walls too. You can use these as room dividers or to replace the existing drywall.
You’ll need:
- Mass loaded vinyl
- Drywall
- Green Glue
- Dynamat (Amazon link)
The method is as follows:
1. Measure and cut your materials
It’s easiest to assemble these on a sheet of drywall, which is usually 4ft x 8ft. Cut your MLV and Dynamat to these dimensions now for easier assembly.
Of course, if you’re replacing existing drywall, ensure pieces are cut to the right size for the room.
2. Begin assembly
Starting on the backside of one sheet of drywall, add a layer of Green Glue. The manufacturer’s guidelines state you need 2 tubes per sheet squeezed over in a random pattern.
Put a layer of mass loaded vinyl on top. As Green Glue isn’t an adhesive, you’ll need to use staples or tacks to hold it in place.
Green Glue takes roughly 15 minutes to begin curing, so you can add the MLV after this point.
3. Add the middle layer
The middle layer should be made of Dynamat or any other sound deadening mat. Its properties are very similar to mass loaded vinyl, but it’s very effective at deadening sound waves of all frequencies.
At a push, you could use something cheaper, such as neoprene mat (Amazon link).
Of course, this isn’t specifically a soundproofing material so don’t expect wonders. You’ll need several layers of it too.
4. Add the outer layers
To finish this off, you’ll just need to repeat step 2 and attach it with the drywall facing out. You should end up with a sandwich containing sound deadening mat and MLV.
You can now fix this to the wall or put it on casters and use it as a room divider. If you’re using it as a wall, be sure to fill the wall cavity with insulation too.
Is More Drywall Worth it?
One question I often get asked is whether you get good results from simply adding more drywall to an existing structure.
The short answer is no. While extra drywall will make a difference to the level of sound transfer, it’s not a good soundproofing material, to begin with.
Essentially you’ll be wasting your money on a thin and rigid material that won’t add enough extra mass to really do anything.
So Which is Better, MLV or Drywall for Soundproofing?
I’d hope by this point that the answer to this question is obvious. Mass loaded vinyl is clearly the better product for soundproofing, if only because it was designed for this purpose.
MLV is mass-rich and flexible, meaning it dissipates sound waves that come into contact with it. A high level of mass also makes it harder to vibrate in the first place.
Drywall is basically the opposite: it’s thin, lightweight, and rigid. While this is great for construction, it’s bad for soundproofing.
Some Final Thoughts
Hopefully, this article has highlighted the benefits of MLV vs. drywall for soundproofing.
MLV is a versatile and effective product that can be used in almost any soundproofing project.
While it can be expensive, it’s definitely worth the investment.
My advice, however, is to use it alongside other soundproofing products to get the most out of it.
