Cotton has many uses and is utilized to create clothing, towels, and coffee filters. Though, you may not know that cotton is also used to make sound-absorbing products. Yet, is cotton good at absorbing sound?
Cotton does absorb a lot of sound. Cotton is porous and fibrous, allowing it to absorb sound by trapping that sound within its fibers. When used properly, it’s as effective as other sound-absorbing materials, such as foam and polyester, and is often used for insulation and noise reduction purposes.
In this article, I’ll go into more depth about why and how cotton absorbs sound and compare it to other soundproofing materials. I’ve also included some additional resources you can take a look at if you’re interested in using cotton for soundproofing.
Also read: 4 Natural Sound Absorbing Materials
How Does Cotton Absorb Sound?
Cotton absorbs sound because it’s a porous material. Sound energy enters the openings of the pores and then bounces around within the cotton, dragging on the sides of the material. This ultimately dulls the vibrations and thus, the noise that can be heard, as the sound converts into heat energy.
However, the position of this cotton is going to matter. As sound absorption works by taking this energy and converting it to heat, the placement of your cotton and the sound you’re trying to block will matter.
According to Dennis Folley, an acoustic professional, there is no “one size fits all” sound-absorbing material, which is explained in the following video:
He continues to say that the best material choice will depend on the room it’s going to be in, as the air amplitude will vary in different rooms, and therefore, the speed of the sound impacts the effectiveness of other materials differently.
Nonetheless, he does mention that cotton is one such material found to be most effective. At the end of the day, this is because it’s fibrous and porous, which allows for the conversion of sound to heat.
How Sound Absorption Works
Sound absorption works through a pretty complicated scientific process, but, simply put, sound absorption works by converting sound to heat. The sound energy that creates the noises you hear is then lost or minimized.
If you’re interested in hearing an expert talk about this process, here’s a video in which Dennis Folley speaks about sound absorption:
In this video, he essentially states that sound absorption isn’t precisely sound absorption but sound loss, as the sound turns into something new (heat) and is lost in the process. Ultimately, this process requires air movement (which happens constantly) because it helps the sound change into heat.
How Cotton Compares to Other Sound-Absorbing Materials
The best sound-absorbing materials will be mostly air, as sound needs to be able to penetrate it. Let’s look into some other airy materials and how they compare to cotton.
Foam is a popular option for sound absorption. Acoustic foam and cotton are both found to be highly effective against noise. The only real difference is that you will need more cotton to absorb the same amount of sound foam panels would.
Simply put, cotton is just about as effective as foam, but you’ll need more to achieve the same levels of noise absorption.
Polyester is a synthetic material that is sometimes used for sound absorption. Polyester works the same way cotton does, absorbing sound through its pores and turning it into heat energy. The polyester used in noise-absorbing products is similar to cotton, but it’s synthetic.
Because this product is synthetic, it’s more uniform, which is why it absorbs sound slightly better than natural cotton will.
Is Cotton Used Commercially for Sound Absorption?
Cotton is used commercially for sound absorption, as it’s effective and available in many different forms. Businesses specializing in sound absorption usually have options made from cotton. These forms are almost all economical when compared to alternatives and effective against noise.
Cotton Is Used for Insulation and Noise Reduction
Commonly, cotton is used commercially in products made for insulation, and cotton-based insulation is known for its effective soundproofing abilities.
One such example is an option like Frost King Multi-Purpose Insulation (available on Amazon.com).
It’s made from recycled denim, which is a sturdy, warp-faced textile that creates a dense weave, making it perfect for use in noise reduction. In fact, one reviewer states that it “works great for specific soundproofing applications.”
If that’s not enough proof, this insulation was determined to “absorb sound better than needle-punched cotton fabrics” by researchers studying the effectiveness of cotton materials for sound absorption in the American International Journal of Contemporary Research.
How To DIY Cotton Sound Absorbing Material
You can use cotton to make acoustic panels right in your home. Almost all DIY inexpensive soundproofing guides ask you to use towels, which are, you guessed it, often made out of cotton! These towels are layered and inserted into a self-made wooden frame.
As we learned earlier, foam and cotton are equally as functional if enough cotton is used. So, layering the cotton, as is done in the tutorial, may make these DIY panels even more effective than foam!
This tutorial itself shows that cotton does indeed absorb a whole lot of sound! As the sound penetrates this cotton, it bounces its way around throughout its pores and converts into heat energy. Cotton is a fantastic and economical way to reduce noise that is proven to be incredibly effective.
Whether you’re looking for something to soundproof a room or just curious about the sound-absorbing abilities of cotton, I can assure you that cotton does, indeed, absorb a large amount of sound.
It’s capable of doing this because its pores, which are full of air, take in noise, or sound energy, which drags along the cotton, reducing the sound. Ultimately, cotton is an excellent option for soundproofing or noise-canceling material.