plywood vs drywall soundproofing

I live in a very noisy area, but I needed my office to be very quiet and block out the external noise. This got me wondering, drywall vs OSB vs plywood vs MDF for soundproofing: which is better? After thorough research, I have some interesting findings that I’d like to share with you.

Drywall is the most cost-effective and the most noise-reducing since it has the most mass. Plywood is the least effective since sound transfers quickly through the wood. OSB and MDF have similar soundproofing characteristics as drywall, but they have other drawbacks that make them a less optimal choice in many situations.

Although they have similar abilities to block noise, these materials all have their own strengths and weaknesses that make them more or less applicable for building a soundproof wall. None of these materials on their own will be soundproof. Let’s discuss the benefits of one material over another, and some ways to make them more effective at reducing noise.

Principles of Soundproofing

When trying to make a wall or other structure soundproof, there are four main principles to take into consideration. These are:

• Mass
• Absorption
• Damping
• Decoupling

On their own, each of these principles of soundproofing is only moderately effective. To reduce sound transmission, you’ll need to combine the effects of several or all of these concepts. Let’s take a look at what each one is and how we can improve them for more effective soundproofing.

Mass

Mass is the amount of material between your sound source and the area you are trying to keep quiet. For sound to pass through a wall or other surface, it must cause it to vibrate. The more material that it must vibrate, the heavier it will be, making it harder to cause these vibrations.

The most simple way to increase the mass of a surface you wish to soundproof is to double layer it. If you’re building a wall, you would use two layers of ⅝” drywall to create the most mass. If you were building a soundproof box for a compressor, you would build one box inside of another to increase the mass.

While increasing mass does improve soundproofing abilities, it’s not enough on its own to make something soundproof. On a standard, single-stud wall, doubling the layer of drywall will result in a noise reduction of about 5db. For a little perspective, a normal conversation is about 60db.

Absorption

Absorption is how much of the sound’s energy gets reduced as it passes through the wall. This will be taken care of by a low-density medium such as fiberglass insulation in walls. If you were building a soundproof box for a compressor, absorption may be performed by styrofoam or even sound control foam.

Damping

Damping is the most effective soundproofing principle for low frequencies. This is a layer that will be added between two stiff panels such as drywall and acts to stop vibrations by converting their energy into heat.

Green Glue noise proofing compound is currently the most effective dampening agent, and it will be discussed more in-depth later in this article.

Decoupling

Vibrations are most effectively carried out through physical contact. Decoupling is when you put space in between the separate parts of a structure so that they can’t transfer vibrations directly.

To achieve decoupling in a wall, you would stagger the studs so that the inside and outside drywall are attached to different sets of studs.

How is Soundproofing Measured?

The noise reduction characteristics of different materials are measured on a scale called the Sound Transmission Class or STC levels. The higher a material’s STC rating, the more sound it blocks. A standard wall will have an STC rating of 35-45.

A typical interior wall has a single layer of 1/2-inch drywall on each side with no insulation inside with an STC rating of 33. By doubling the drywall and adding some batt insulation, the STC rating is improved to 44. A reduction of 10 STC levels results in an apparent sound reduction of 50%.

Drywall vs OSB vs Plywood vs MDF for Soundproofing

Although each of these materials is very similar in terms of soundproofing effectiveness, they have very different qualities that make them more or less suitable for different applications. Here we will look at each material more closely and see how they stack up.

Drywall

Drywall is the most cost-effective option and is the go-to choice for double layering walls. This is in large part because it is much more moisture resistant than the other materials.

It is also much easier to cut and attach than other materials such as MDF that must be cut with a large saw, while drywall can be cut with a utility knife.

Regular drywall has a very similar STC to plywood, OSB, or MDF. However, it is much cheaper and can be double layered for the same price or even less than a single layer of MDF.

For improved soundproofing, Quietrock drywall is the best way to go. Quietrock is sheetrock that has an improved STC rating while still having the benefits of gypsum board. If you’d like to learn about Quietrock vs double-layered drywall, read this article.

Drywall has a density of about 650 kg/m3.

Pros

• Not moisture absorbent
• Very cost-effective
• Sufficient STC rating
• Easy to work with
• Lighter than other materials of the same thickness

Cons

• Not very strong
• Can be difficult to finish and may require a professional

Price

The price of drywall depends on the thickness. Standard interior walls are usually covered with ½” drywall that goes for just under $12 per 4’X8’ sheet.

To increase the mass, and thus the soundproofing, I recommend using ⅝” type X drywall instead, which currently costs about $14 per sheet. This is the most cost-effective way to add mass to your interior walls.

Medium Density Fiberboard (MDF)

Medium Density Fiberboard (MDF) has an STC rating similar to drywall, although it has a higher density. However, it is much heavier and harder to work with.

It is also held together with chemicals called VOCs that are released when you cut the board, making this much more difficult to deal with than drywall.

MDF is very strong, and if you need structural integrity to come from the panels you are using, then MDF may be the way to go.

MDF has a density of about 720 kg/m3, making it the densest option for soundproofing.

Pros

• Very Strong
• Sufficient STC levels
• Holds screws very well
• Very Smooth
• Easy to paint

Cons

• Very moisture absorptive
• Very heavy compared to same thickness drywall
• VOCs released when it is cut
• Expensive

Price

Similar to drywall, the cost of MDF will change with the thickness. A 4’X8’ sheet of MDF that is ½” thick is about $25. A ⅝” thick piece is $30. You can see how this would add up quickly if trying to cover walls in a double-layer of MDF!

OSB

OSB has similar soundproofing qualities as drywall or MDF. It is considerably cheaper than MDF and doesn’t absorb water as quickly. However, it holds on to moisture for a very long time when it does get wet, which is why it isn’t used in walls.

While OSB is not as strong as MDF, it is stronger than sheetrock and could be used in applications where support is needed.

Unlike MDF, the adhesives used in OSB gas off naturally and will not release harmful VOCs when cut.

OSB has a density between 600-680 kg/m3.

Pros

• Strong
• Cheap
• Doesn’t absorb water fast

Cons

• Holds moisture for a long time
• Splinters
• Harder to work with than drywall
• Doesn’t look great/not a finished product

Price

OSB comes in slightly different thicknesses than the other materials we’ve discussed. A 7/16” thick 4’X8’ sheet of OSB costs only $9. However, this is thinner than the ½” drywall and will provide less soundproofing. A 15/32” sheet of OSB is just over $15, making it a bit more expensive than drywall of a similar thickness.

Plywood

Plywood is not nearly as dense as OSB or MDF, which means it is not quite as effective at blocking sound transmission. Many types of plywood are available that range in cost, finish, thickness, and kind of wood used.

Basic plywood sheathing used in construction has a density of 460-520 kg/m3. A hardwood, finish plywood sheet has a density of 620-680 kg/m3.

Pros

• Very Strong
• Not as susceptible to water damage
• Holds screws well
• Low to No VOCs

Cons

• Not very dense
• Splinters easily
• Hard to cut and work with
• Not the best soundproofing characteristics
• Expensive

Price

The price of plywood changes dramatically based on factors such as the type of wood used, the thickness, and the adhesive.

A 15/32” sheet of non-sanded sheathing plywood currently costs about $17, which is $2 more than a comparable sheet of OSB. The same size sheet in sanded plywood would cost $26, almost on par with the much denser MDF.

If you went with higher-end hardwood plywood, a single ½” sheet would cost about $46, making it the most expensive material on this list.

MDF vs Drywall for Soundproofing

Since MDF and drywall do have similar soundproofing capabilities, there are different applications where you might choose to use one material over the other.

On interior walls where a lot of coverage is necessary and a finished look must be achieved, drywall is the definite choice. Sheetrock is not absorbent; it finishes well and is easy to install. Because drywall is so much more cost-effective, you can also double-layer it for less than a single layer of MDF, giving you more density and improved sound reduction.

On the other hand, MDF is much stronger than drywall and can be used in situations where structural support is necessary. MDF would be the best choice for an inside unit such as a soundproof box for a compressor. MDF is also the go-to choice in applications such as home theatres and soundproof doors.

Plywood vs MDF for Soundproofing

While MDF is the go-to choice for many indoor soundproofing applications, there are situations where it is not optimal because of its water-absorbent properties.

Plywood would be the choice for sheathing your floor since non-sanded sheathing plywood is so much cheaper than MDF and is more resistant to moisture. To make the floor more soundproof, you could also add a second layer of plywood or a layer of insulation underneath.

Drywall vs OSB for Soundproofing

Both drywall and OSB have similar characteristics for soundproofing, and they are also priced very close to each other. So where would each one be the better option?

As discussed, drywall is the best choice for covering interior walls for many reasons. On the exterior walls, however, OSB is superior. It does not absorb moisture very quickly, and since it is so cost-effective, it can easily be double-layered for additional mass.

Because it is much stronger, OSB can provide the structural integrity necessary for sheathing external walls.

MDF vs OSB for Soundproofing

MDF and OSB are both very strong and have similar applications. Although MDF is denser, OSB is so much cheaper that in many applications you could double-layer it for the cost of a single layer of MDF. Of course, this would make your unit extremely heavy and is not recommended for something mobile.

OSB can also be used in any exterior applications, which MDF wouldn’t be a good choice for because of its water-absorbent properties. This makes OSB the best choice for an application such as a soundproof shed for air compressor.

How to Improve Noise Reduction

When you’re trying to make a space quieter by implementing soundproofing techniques, there are several ways you can improve the noise reduction. In this section, we will cover several different ways to improve your soundproofing.

Add Insulation

Insulation will provide absorption, one of our 4 principles of soundproofing. This will help kill the energy that the audio waves contain, stopping them from being transmitted.

Insulation can be added inside of interior walls to reduce noise transmission. It can also be added to floating floors to decrease vibrations further. Insulation can be used almost anywhere; there is an open space that sound transmission needs to be reduced.

There are many different types of insulation available. While standard fiberglass insulation does offer some dampening benefits, there are other options such as sound guard Rockwool that will provide even better soundproofing. For more information on different types of insulation and how they improve soundproofing, check out this article!

Increase Mass – Add More Material

This improvement relates to the soundproofing principle of mass. By using thicker material, or adding additional layers, we are creating more mass for the vibrations to attempt to move.

On interior walls, this would be achieved by double layering the drywall. On an exterior wall, you could achieve this by double layering OSB. If you were building a soundproof box for a compressor or vacuum, you could do this by building a box within a box, effectively creating two layers the sound must pass through.

Use Acoustic Drywall

Instead of doubling up on your drywall layers, you could try using acoustic drywall such as QuietRock. QuietRock alone can improve your STC rating by 15-20 points! For more information about this, check out my article on QuietRock here.

Resilient Channels and Sound Isolation Clips

Resilient channels are thin metal strips that attach to a wall, on top of the first layer of drywall. The second layer of drywall is then mounted to these strips, effectively decoupling the second layer of drywall from the rest of the wall.

Sound isolation clips work under a similar premise, except they attach directly to the studs. The rubber-backed clips are mounted to the studs, and then a metal channel is attached to the clips, running perpendicular to the wall studs. The drywall is then fastened to these metal channels.

Both resilient channels and sound isolation clips work by decoupling your wall from the outside and are very effective for improving soundproofing qualities.

Wall Studs

When you’re building walls that you want to be soundproof, opt for metal studs over wood studs. This change alone will result in a decrease in reduction by about 5db. Metal studs are not as rigid, and therefore they do not transmit the vibrations as easily as wood studs do.

For maximum soundproofing, you can stagger your studs, so that the inside and outside layers of the wall are each attached to their own set of studs. This is the decoupling principle of soundproofing in action.

Note: For another soundproofing wall option, please check out our article How to Build a Soundproof Room-Within-a-Room.

Use Mass Loaded Vinyl

Mass loaded vinyl or MLV is a rolled membrane that can be used to cover any surface to drastically reduce the sound that’s transmitted through. Because it is a very viscous material, it stops vibrations and is one of the most effective soundproofing materials available.

MLV is most effective when applied between layers, such as in between to sheets of drywall. MLV is very expensive, however and is best used when the price is not a factor.

Green Glue

Green glue is currently the most effective form of dampening available for soundproofing. It is applied between two panels, such as two sheets of drywall. It acts as a flexible, sound-absorbing layer that stops vibrations.

This is very easy to use and effective method. To use green glue to improve the soundproofing of your walls, you would simply apply it to the back of a piece of drywall, and then screw that drywall sheet to your existing wall. You now have a double-layered, dampened wall that even without any insulation inside, and without being double layered on the other side, will improve to an STC level of 43!

Conclusion

Depending on what you’re trying to soundproof, OSB, MDF, plywood, and drywall all offer soundproofing characteristics with their inherent advantages and drawbacks. After reading this article, hopefully, you understand which one best suits your particular needs!

If this article was helpful to you, feel free to share it so that it can reach other people who may also find it helpful. As always, comments and questions are appreciated and can be left in the comment section below.