Is 1-Inch Acoustic Foam Enough for Soundproofing?

If you reside or work in a noisy neighborhood, you’ll sooner or later decide to soundproof your room or office. Acoustic foam is a popular item in the world of sound management, so it might have been the first solution to pop into your mind. Acoustic foams range from 1 to 4 inches (2.54-10.16 cm) in thickness, but is 1-inch (2.54 cm) foam enough for soundproofing?

A 1-inch (2.54-cm) acoustic foam isn’t enough for soundproofing. It can only cushion the effect of sound produced in a room. A 1-inch (2.54-cm) acoustic foam absorbs sounds in high and mid frequencies. So it’s best used for rooms that don’t require complete sound absorption.

Soundproofing and sound absorption are different concepts. I’ll shed more light in the following sections and show you how best to use acoustic foams.

Soundproofing vs. Sound-Absorption
- Soundproofing
- Sound Absorbers
Acoustic Foam: What To Expect
How Do I Know How Many Inches of Acoustic Foam To Use?
Conclusion

Is 1-Inch Acoustic Foam Enough for Soundproofing?

Soundproofing vs. Sound-Absorption

It’s easy to confuse soundproofing with sound absorption. While some materials can function in both ways, these terms represent different concepts.

Soundproofing

Soundproofing refers to blocking sound from filtering into or out of a room. Soundproofing materials, therefore, can prevent sound from entering a room or leaving the room.

If you soundproof your room, you’ll no longer deal with noise from traffic, loud neighbors, construction sites, etc. Also, if you’re a loud person or enjoy your loud music, rest assured that no angry neighbor will knock on your door in protest.

Still a bit confused? Read on.

Sound travels in waves, and it needs an outlet when it is released. If there is no outlet, it hits the walls and ceilings and bounces all around the room until it dissipates.

When it bounces back, it causes an echo or reverberation. If you want to stop this from happening, you’ll need to layer your walls with a material that can catch the sound and stop it in its path.

This is where soundproof materials come in. Soundproof materials must be thick and heavy in order to trap the sound waves and stop them from going out or bouncing back.

Here is a list of soundproof materials for various areas of a room:

Soundproof doors
Drywall
Inserts
Mass loaded vinyl
Soundproof curtains
Soundproof room dividers
Rugs and carpets
Double glazing
Green glue

Sound Absorbers

As the name implies, sound absorbers are materials that soak in sound to reduce its effect. Sound absorbers don’t block outgoing or incoming sounds. Instead, they absorb the sound in a room so it doesn’t bounce. They soak in the echo and vibrations released.

Let’s say you install a sound absorber in your room so you can use it as a recording studio. It’ll help make the place quieter for clearer songs without any echo in the background. However, it won’t stop you from hearing the music coming in from your loud next-door neighbor.

As the sound waves move, the sound absorber collects them like a sponge and converts the energy absorbed to heat.

Sound absorbers are like helmets. They reduce the effect of a hit. It doesn’t mean you won’t feel anything, but the effect will be smaller than if you were not wearing a helmet.

Unlike the hardness and thickness of soundproofing materials, sound-absorbing materials are soft, flexible, and porous.

Here’s a list of sound-absorbing materials:

Foams
Ceiling clouds
Acoustic panels
Fiberglass insulation

Acoustic Foam: What To Expect

Acoustic foams may not soundproof a room, but they have many great features. Here’s what to expect with acoustic foam:

Absorbs sound (echo, sound waves, and vibrations)
Easy to install and work with.
Quite affordable.
It absorbs 90-100% sound the thicker it gets.
It has a variety of sizes, colors, designs, and thicknesses.
It can be used in restaurants, schools, churches, studios, rooms, podcast rooms, gaming rooms, theaters, and anywhere else noise needs to be suppressed.
Little or no health hazards.
It lasts for 5-7 years if properly handled.
It can take on mild stress without falling apart.
It’s soft and flexible.
It’s made of polyurethane, which makes it a fire retardant.
It improves sound quality in studios and theaters.

In addition to thickness, placement is also an important factor when it comes to acoustic foam. That brings up an interesting question: should you install acoustic foam behind speakers? I’ve written a detailed answer, which you can read by clicking on the link. Should You Put Acoustic Foam Behind Speakers?

How Do I Know How Many Inches of Acoustic Foam To Use?

If you’re planning on using acoustic foam to pad the walls of your studio, you’re probably wondering how many inches can give you the desired effect.

First, you should ask yourself a couple of questions:

What kind of sound is produced in the room?
What is the purpose of the room? Are you creating a home music studio or a YouTube studio, or do you want a room that doesn’t echo your every word?

When you’ve decided what you want to use the room for, you can now determine how thick the acoustic foam should be.

1-inch (2.54-cm) thick acoustic foams: One-inch thick foams are best for rooms that don’t require complete sound elimination. They can also be used in schools and restaurants.
2-inch (5.08-cm) thick acoustic foams: Two-inch (5.08-cm) thick acoustic foams are a bit better at providing sound absorption. They’re best used in home recording studios, podcast studios, or other non-professional but still high-quality DIY scenarios.
3-inch (7.62-cm) thick acoustic foams. They can absorb high, mid, and low frequencies. They’re used in recording studios, theaters, and in other professional scenarios.
4-inch (10.16-cm) thick acoustic foams. Do you want to completely eliminate high, mid, and low-end sounds? Then go for 4-inch (10.16-cm) thick acoustic foams. They can be used anywhere—especially in professional studios, where total sound absorption is required.
Bass trap. As its name implies, it traps bass sounds. Bass traps are the thickest acoustic foams and are suitable in rooms with bass equipment such as bass guitars, drum kits, subwoofers, etc.

If you don’t have acoustic foam, one option may be to use a blanket. Find out if using a weighted blanket for recording gets the job done. Will a Weighted Blanket Block Sound for Recording?

Conclusion

One-inch (2.54-cm) acoustic foams cannot soundproof a room because acoustic foams are not soundproof materials—they’re sound absorbers.

If you aim to block sound from entering and going out of a room, then acoustic foam is not what you need—you need soundproof material.

Acoustic foams only cushion sound in a room. The thickness of an acoustic foam determines its sound absorption capacity. The thicker the acoustic foam, the more sound it will absorb.