A Guide to Soundproofing Materials

Residential and commercial soundproofing is common for many reasons, from providing noise reduction to enhancing room acoustics to achieving echo reduction. However, the process depends on various factors to successfully solve noise problems, including the area that needs soundproofing and the type of noise that needs reducing. For example, creating a quiet environment for working at home will require different soundproofing materials and techniques than improving acoustics in a recording studio.

Today’s guide includes an in-depth look at the different soundproof materials available, including how soundproofing works, its fundamental principles, and which materials are best suited for reducing different types of noises.

Soundproofing is all about noise control. In general, sound reduction uses materials and soundproofing techniques for two purposes: reducing sound transmission from one area to another (i.e., reducing outside noises from entering a home) or controlling the transmission of sound within the space (i.e., dampening loud music from within a nightclub). Sound proofing techniques help create environments where unwanted noise is minimized by either buffering or containing the sound.

Understanding how soundproofing works begins with understanding sound itself. Sound travels through air, solids, and liquids in waves. When these soundwaves encounter a barrier, they can pass through, bounce off, be absorbed, or bend/break up (i.e., diffract). Therefore, the key to any type of soundproofing is selecting the right material to disrupt or absorb the travel of the soundwave (i.e., sound transfer) within a space.

However, there is not a one-size-fits-all solution to reducing or absorbing sounds. Determining which soundproofing solutions best fit your needs depends on the specific requirements of your space, the type of noise you want to block or reduce, and your budget. Therefore, it’s essential to understand the key principles of soundproofing to ensure the proper soundproofing materials are selected for the space.

Understanding these principles is critical to selecting suitable materials and implementing the proper soundproofing techniques to control or reduce unwanted noise in any space.

Deflection

Deflection involves using mass to bounce sound waves away from an area. For example, placing a sturdy, solid obstacle between your home and a noisy street, like a brick wall, can help bounce the traffic noise away from your house. The more mass a barrier holds, the better it becomes at blocking sound transmission. In other words, heavier and denser materials impede sound waves more effectively than lighter ones.
Absorption
Sound absorption involves using materials that capture sound waves and convert them into a small amount of heat, reducing sound reflections and reverberations within a space. Much like a sponge absorbs water, there are specific acoustic materials that absorb sound energy. It’s important to remember that absorption does not block sound but reduces the amount of reflected noise within a space.

Decoupling

The principle of decoupling involves preventing soundwaves from traveling in continuous paths by creating separation between structures. The sound transmissions, i.e., noises, are interrupted and significantly reduced by breaking a sound wave’s path. Decoupling is more of a structural approach to sound proofing, as it involves mechanically separating the two sides of a wall or surface to make it harder for sound to pass through.

Damping

This sound reduction principle, often called constrained layer damping, involves using a dampening compound between two rigid layers, such as drywall. When sound waves encounter a barrier, they cause the material to vibrate. These vibrations can pass through materials and structures, leading to sound transmission from one side of a barrier to the other.

Damping reduces the vibrational energy of sound waves within materials, converting it into heat through internal friction. This thermal conversion process helps mitigate sound transmission by absorbing the kinetic energy from sound waves.

Sealing

Sealing, as the name implies, involves using acoustic caulk, weather stripping, or alternative materials to seal gaps, cracks, and openings in walls, windows, doors, and floors to help prevent sound leakage.

As already mentioned, there is no best or one-size-fits-all sound proof material. Different soundproofing materials address different noise reduction or sound absorption needs. As outlined in the above principles, a noise proof material serves a purpose, typically including sound dampening, sound deadening, sound insulation, or sound absorption.

Depending on the type of noise, you can use these materials alone or together to provide a noise barrier, sound isolation, or acoustic treatment in a space. Let’s explore the best soundproofing materials based on an area’s noise control needs.

Sound dampening limits the amount of noise that leaves or enters a room. The best sound dampening material reduces the vibrational energy of sound as it passes through the soundproof materials, effectively reducing noise within a space. Following are a few examples of sound dampening materials.

Viscoelastic Damping Compound

These sound absorbing materials are excellent for sound dampening due to their ability to absorb and dissipate sound vibrations. This sound proofing material effectively reduces sound transmission and improves the acoustic environment by converting vibrational energy into heat. Their unique viscous and elastic properties make them versatile and one of the best sound absorbing materials for walls, floors, and ceilings. Common examples of this soundproofing material include Green Glue and polyurethane foams.

Sound Dampening Drywall

This specific form of drywall includes layers of gypsum and viscoelastic polymers for sound dampening. Although these sound absorbing materials for walls may be more expensive than standard drywall, they are excellent sound dampening materials, enhancing soundproofing performance in areas.

Resilient Channels

Resilient channels are metal devices that decouple and soundproof rooms and buildings—these devices separate drywall from framing, reducing sound transmission by interrupting the soundwave path. Resilient channels are an economical solution for soundproofing walls and ceilings, suitable for commercial and residential soundproofing.

Sound deadening is a sound reduction technique that blocks and reduces sound waves through barriers. The best material for sound deadening has a high mass and solid core. Following are a couple of popular and effective options.

Mass-Loaded Vinyl (MLV)

Unsurprisingly, the most versatile, best sound deadening material includes vinyl. MLV is a dense, flexible soundproofing material constructed of vinyl and another high-mass ingredient, like calcium silicate or barium sulfate, that amplifies the material’s density to impede sound. MLV is an easy-to-install, water-resistant, noise proof material usually added to walls, floors, and ceilings for sound proofing.

Soundproof Doors

These STC-rated, sound deadening doors are specially designed with solid cores and soundproofing materials to inhibit sound transmission. An STC rating quantifies the ability of a structure to block sound. The ratings typically range from 25 to 75, and higher STC ratings indicate better sound blocking performance.

Sound insulation is a method used to reduce sound between spaces with materials that absorb or block sound waves. The best sound insulation material is fibrous or foamy, and installing it in walls, floors, ceilings, and doors helps minimize noise transfer. The following sound barrier insulation types are good soundproof materials for this technique.

Fiberglass Insulation

This fibrous material isn’t just for thermal insulation – it’s also a good soundproofing material. Fiberglass insulation is made from fine glass fibers, sometimes including a formaldehyde-free binder to hold the fibers together. This soundproof material for walls, floors, and ceilings effectively absorbs sound waves, reducing noise transmission between rooms, and is available in batts, rolls, and loose-fill.

Mineral Wool Insulation

This sound absorbing insulation consists of natural rock, like basalt, or recycled slag from steel mills. Like fiberglass, this soundproof material is available in batts and rolls. However, it’s also available in rigid boards. Ideal for walls, ceilings, and floors, this high-density insulation offers excellent sound absorption, making it one of the best soundproof insulation options. It also has the added benefit of being water resistant.

Blown-in Cellulose Insulation

The last in this list of insulation sound resistant materials is blown-in cellulose. This sound insulation material is loose-fill insulation made from recycled paper products treated for fire resistance, making it a very eco-friendly sound proof insulation option.

Sound absorbing materials are ideal when the goal is to reduce echoes and improve acoustic quality within a space, such as a listening room, recording studio, or home theater. While soundproofing aims to block sound from entering or leaving a space, sound absorption focuses on managing and controlling sound within the space.

Acoustic Panels

Acoustic panels are excellent for absorbing sound and reducing the amount of reflected noise bouncing around the room. These panels consist of sound absorbing materials like foam, fiberglass, or mineral wool and come in various shapes, sizes, and colors, offering a decorative solution for reducing reflected noise and echo.

Acoustic Foam

Acoustic foam features an open-cell structure that absorbs sound waves. This specialized foam’s unique design increases the surface area interacting with sound waves, enhancing absorption to reduce overall noise and improve sound clarity. This sound absorbing material is lightweight and easy to cut and install to fit various space requirements.

Bass Traps

Bass traps are essential acoustic treatments made from acoustic isolation material, including fiberglass, mineral wool, or acoustic foam, designed to absorb low-frequency sound waves. Available in various shapes, such as triangular, rectangular, and cylindrical, they strategically fit in corners and along walls to effectively reduce bass buildup and improve room acoustics.

Now that you have a general understanding of the best soundproofing materials, the next step is determining what kind of noise control a space needs for effective soundproofing. Next, we’ll examine the different types of noises that commonly affect spaces, including what soundproofing materials and techniques offer the best control.

Airborne Noise

Airborne noise travels through the air and can penetrate walls, floors, and ceilings. This type of sound includes talking, music, and traffic, to name a few. This noise is the most prevalent and easily remedied by various soundproofing techniques using appropriate sound absorbing materials. Depending on the space, sound blocking strategies like sealing gaps and cracks, adding mass, decoupling, and incorporating absorption materials can significantly reduce airborne noises and create a quiet environment.

Impact Noise

Impact noises are sounds that travel through floors and walls in a building. Common examples of impact noises are footsteps, objects dropping, or furniture moving. The principles of soundproofing that best quiet impact noises in spaces include absorbent flooring (i.e., carpeted or padded floors), decoupling ceilings, and padding walls with acoustic panels.

Structure-Borne Noise

Structure-borne noises are vibrations that travel through a building’s structure, causing noise in different parts of the building or home. These types of noises are challenging and result from various sources, like mechanical equipment (i.e., elevators or HVAC systems), impact noises, or construction activity. Decoupling, damping, adding mass and density to walls, and floor soundproofing can significantly help control sound transmission in areas affected by structure-borne noises.

Flanking Noise

Flanking noises are tricky, often bypassing standard soundproofing barriers such as walls, floors, and ceilings. These noises follow multiple transmission paths, usually combining airborne and structure-borne components, including through outlet gaps or floor framing. An example is when someone watches TV in the living room, and another can easily hear the sound in a room on the other side of the house. Depending on the source and pathway of the sound, a combination of soundproofing techniques like sealing gaps and cracks, insulating ductwork with acoustic insulation, soundproofing doors/windows, decoupling structural elements, and adding mass and density where applicable can help.

Soundproofing a space can create a quieter environment for home offices, theater rooms, or gaming spaces. Whether the goal is to keep noise inside or outside a room or improve the overall acoustic performance, it’s manageable with the right combination of soundproofing materials and techniques. Although many soundproofing solutions are simple enough to DIY, larger, more complicated projects require expert help. If you have questions about soundproofing a space in the Los Angeles area, MIR Audio Video can help.