8 Best Insulation Materials For Soundproofing And Acoustics

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Do you live in a busy neighborhood? Maybe you have a large family and need to shut out some of the noise. Perhaps your teenager insists on blaring their radio or playing their electric guitar way too loud. For whatever reason, you need insulation that aids in soundproofing and acoustics. We scoured the internet for the best soundproof insulation materials. See our findings below.

When it comes to soundproofing and acoustic treatment, the following insulation materials are best:

  • Mineral wool
  • Cellulose 
  • Fiberglass

Don't stop reading just yet. There is still a lot you need to know about soundproofing and acoustic treatment. Follow along as we discuss the difference between soundproofing and acoustic treatment, whether or not soundproof insulation offers thermal benefits, the best R-value for soundproofing, and more. Without further ado, let's get into it!

A sound engineer workplace, 8 Best Insulation Materials For Soundproofing And Acoustics

Soundproofing Vs. Acoustic Treatment

Before you begin purchasing insulation for your home, it's important to understand the difference between soundproofing and acoustic treatment. Not all insulation will double as an agent for both.

Soundproofing

Woman covering ears

If you live in a busy neighborhood or have noisy children, you need soundproof insulation. This insulation keeps sound trapped inside a room while also blocking outside noise from entering.

For example, if you use soundproof insulation in your children's playroom, they will not be able to hear you yelling at them from downstairs or across the hall. Although you may be able to hear muffled sounds from their playroom, it likely will not be loud enough to disturb your peace.

This also means the neighbors won't be bothered by the noise.

Acoustic Treatment

Installing coustic foam

While soundproofing means blocking sound from entering or leaving a room, acoustic treatment is the act of bettering the sound quality of a room. Choir and band rooms are one example of areas that could benefit from acoustic treatment.

Let's put it into perspective. Have you ever noticed that some rooms seem louder than others? Surely you have heard the adage "everyone's singing sounds better in the shower or bathroom."

This is because the acoustics in those rooms are better than in others. Acoustic treatment is usually achieved by placing panels on the walls. This method, however, will not work for soundproofing.

Sound Transmission Class (STC)

Before we get into types of insulation, it's best to understand the ratings. One rating you will see is the Sound Transmission Class (STC).

This rating is a way for consumers to know how well an object reduces sound transmission. The higher the number, the better the object is at reducing sound. The International Building Code requires buildings to have a minimum STC of 50.

According to the Insulation Institute, an STC of 25 means that speech is easily understood between walls. An STC of 35 means you can hear the words coming through the wall but not understand them, and an STC of 50 means that speech cannot be heard between walls.

Mineral wool batts have an STC of 45, while mineral wool panels boast an STC ranging from 45 to 52. Fiberglass batts only have an STC of 39, while fiberglass panels have a slightly higher STC of 44. The STC of loose-fill cellulose is 44, while densely-packed cellulose can have an STC ranging from 44 to 68.

Noise Reduction Coefficient (NRC)

Noise Reduction Coefficient (NRC) is another rating you will see when shopping for insulation. This rating tells consumers how much sound an object absorbs and reflects.

The scale ranges from 0 to 1, with 1 meaning all sound is absorbed and 0 meaning no sound is absorbed. However, this number can sometimes be greater than 1 but less than 2.

The NRC of mineral wool panels can range from 0.95 to 1.09. Mineral wool batts, on the other hand, all have the same NRC of 1.05.

Fiberglass batts only have an NRC rating of 0.85. Fiberglass panels, however, can have NRC values ranging between 0.50 and 0.95. Loose-fill cellulose has a fairly high NRC value of 0.80, while densely-packed cellulose boasts an outstanding 0.90 NRC.

Best Types of Insulation for Soundproofing and Acoustics

Soundproofing

When it comes to soundproofing, mineral wool insulation is the best. It is denser and stiffer than fiberglass and features higher R-values. It also has less of a tendency to become compressed over time, which would lessen both its thermal ability and its sound-absorbing qualities.

Acoustics

If you are more interested in improving the sound within a room, cellulose is your best option. Not only does it reduce vibration resonance but it also absorbs, deadens, and dampens noise. Cellulose, in any form, will greatly increase the sound quality of your room.

Mineral Wool

Stack of thermal insulation material in roll is wrapped with cellophane foil

Mineral wool is lightweight and extremely dense, featuring higher R-values than fiberglass insulation.

Some higher-performing mineral wools boast an NRC of 1.05. Not only does it have excellent sound absorption properties but it is also ideal for improving the sound quality in rooms. Even lower-performing mineral wools have an NRC of 0.852 and reduce both noise and echos.

1. ProRox SL 940 Rockwool Mineral Wool Insulation Board

This three-inch-thick mineral wool insulation board features an R-value of 12.6 per inch of thickness, meaning it will provide an excellent thermal rating of 37.8. What's more, it minimizes the vibration time of soundwaves.

You can view this product on Amazon.

2. Roxul Rockboard 60 Mineral Wool Board

If you are more interested in acoustic qualities than soundproofing, this mineral wool board is for you. It is known for its acoustic values, and many musicians use it when setting up bass traps. Additionally, it features a 4.3 R-value per inch of thickness and a density of 6 pounds per cubic foot.

Click here to see this product on Amazon.

3. Roxul Rockboard 80 Mineral Wool Board

Roxul Rockboard 80 is very similar to Rockboard 60. However, this product features an 8 pound per cubic foot density and an R-value of 6 per inch of thickness. Like Rockboard 60, it is popular for its acoustic abilities along with its use in creating bass traps.

Click here to see this product on Amazon.

4. Rockwool Acoustic Mineral Wool Insulation 60

Rockwool acoustic insulation can double as both soundproofing insulation and acoustic treatment.

It has a 6-pound density with an R-value of 8.4 per inch of thickness and an outstanding 0.9 NRC rating. This pack features rigid, pre-cut boards which are ideal for creating bass traps or applying to the wall as acoustic panels.

Check out these panels on Amazon.

Cellulose

Worker spraying blown fiberglass insulation

If you are planning to install your own blown-in cellulose insulation, you will need a blower machine. If you do not own one, you can usually rent them from Home Depot. Additionally, many stores offer a 24-hour free blower rental with the purchase of 10 bags of insulation.

1. U.S. GREENFIBER LLC INS541LD Fiber Insul 40FT Cocoon

This loose-fill insulation is lightweight and easy to use. It is meant for dry use and can be blown into attics, floors, and walls. Each bag covers approximately 40 square feet. With every 4 inches of this loose-fill cellulose, you get an R-value of about 19.

Click here to view this product on Amazon.

2. BXI Soundproofing Closed-Cell Foam

These closed-cell foam panels are excellent for improved sound quality and feature self-adhesive backs for easy installation. You'll enjoy extra sound absorption and noise reduction, and it can be applied both indoors and outside.

Check it out on Amazon.

Fiberglass

Man installing fiberglass insulation in the wall

1. Certainteed 90007902 R38 16" x 48" Unfac Battery

This fiberglass batt is 13 inches thick and has a total R-value of 38. It's easy to apply and fairly durable with the ability to reduce the noise level, echo, and feedback of a room, making it more suitable for soundproofing than acoustic treatment.

Click here to see this product on Amazon.

2. Owens Corning R-13 Pink Kraft Faced Fiberglass Insulation Roll 

This is a top brand of fiberglass, featuring an R-value of 13 per inch of thickness. At 3.5 inches thick, it is excellent for noise control, and it is also easy to install.

Click here to see this product on Amazon.

What R-Value is Best for Soundproofing?

Many people only link R-value to thermal ability. However, a higher R-value also means better soundproofing qualities.

When it comes to insulation, the thicker the product, the higher its R-value will be, and the more noise it will absorb. Therefore, you should purchase insulation that totals no less than R-19.

To find the total R-value of a product, multiply the given R-value by the inch of thickness. For example, if a product is 3 inches thick with an R-value of 5, you would multiply 3 x 5, giving you a total R-value of 15.

Is Sound Insulation as Good as Thermal Insulation?

Since R-value plays a major role in a product's ability to absorb sound, sound insulation is just as good as thermal insulation. In fact, the two go hand-in-hand.

How Thick Should Sound Insulation Be?

Sound insulation should be a minimum of 1.9 inches thick for walls and 3.93 inches thick for floors.

Is Rockwool Good for Soundproofing?

Rockwool has excellent soundproofing ability. However, some variations will be better suited for acoustic qualities than soundproofing. Just make sure you choose the best product for your needs.

In Closing

When it comes to insulation, choosing the right product for your needs can be a bit overwhelming, especially if you are trying to soundproof your home or improve the acoustics.

To make things simpler, mineral wool is the best insulation for soundproofing, and cellulose is better suited for acoustic treatment. Fiberglass is also a suitable option, but it comes in at the bottom of our list.

For more information about thermal value and soundproofing, take a look at these other posts on our blog:

What's The Best Insulation For Soundproofing Ceilings And Walls?

9 Types Of Thermal Insulation You Should Know

What R-Value Is 6 Inches Of Insulation?

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