Soundproofing Vs. Sound Absorption: The Most Important Differences!


Have you ever wondered about the difference between ‘soundproofing’ and ‘sound absorption’? The majority of people including regular home owners, designers, engineers, building owners and facility managers usually treat these two 2 words as synonyms. But there is a difference and you should probably know it.

Soundproofing is a method of blocking sound from entering or exiting a room, while sound absorption absorbs the sound inside the room, reducing echo in the process. The two methods often overlap since many of the materials can serve both functions. 

But that’s not always the case. For example, some materials such as lightweight acoustic foam help almost exclusively with absorbing sound. Egg crates are another example. Both of these materials are too light to block sound so they’re NOT soundproofing materials. But they’re soft and designed in such a way that they can absorb or trap sound already present in the room, preventing sound reverberation and echo. However, a heavy fiberglass panel installed on a wall can serve both functions: soundproofing and sound absorption. First of all, it’s heavy and dense enough to block noise, and secondly it’s made of soft material that can absorb sound as well.

I highly encourage you to read the rest of this article for a more detailed explanation of both methods and materials. This will help you pick the right products for blocking noise and improving acoustics in a room or a vehicle.

What is Soundproofing?

Soundproofing is a technique that is used to restrict or block any unwanted sound from either entering or exiting a room. In layman’s terms, soundproofing can be referred to as sound blocking or sound insulation. Sound blocking or soundproofing is also used to avoid unwanted noise that can be a result of the reflection of echoes, resonances, and reverberations.

What Are Soundproofing Materials?

Soundproofing materials are products that stop or block sound from entering or leaving a room. Here are some of the common properties of soundproofing materials:

  • They are cumbersome (large and heavy)
  • Density: Denser and heavier materials are generally better at soundproofing (mass loaded vinyl, fiberglass..)
  • Tortuosity: Tortuosity is the measure of the twists and turns in the material’s cell arrangement. Soundproofing materials have more twisted cells
  • Porosity: Soundproofing is less porous
  • Flow resistivity: Flow resistivity is defined as the flow resistance to noise per unit thickness of a material

How Does Soundproofing Work?

Soundproofing can be achieved in 4 different ways, and these are:

  • Dampening– Oscillating sound waves are made to undergo resonance, concerning the surface it hits. In simple words, dampening is the process by which sound waves and vibrations are dissipated before they build up and radiate sound.
  • Add/increase Mass or Density – Sound waves lose more energy when traveling a longer distance. Therefore, one way to soundproof space is to add more mass or density to it.
  • Decoupling – Sound-waves are nothing more than vibrational energy that travels through a medium. If you introduce gaps or you decouple the medium, the vibrations get interrupted and so, sound can no longer be conducted.
  • Absorption –Soundproofing through absorption occur when sound waves hit a surface and get absorbed within the material.

Where is Soundproofing Used?

Soundproofing can be applied to commercial buildings and other places including:

  • Backyards
  • Theatres
  • Cinemas
  • Front yards
  • Restaurants
  • Offices
  • Schools
  • Hospitals
  • Home theaters
  • A recording studio
  • Around firing ranges
  • Hotels
  • Conference centers
  • TV/Radio studios

What Are the Common Materials Used for Soundproofing?

A wide variety of soundproofing materials are available in the market today. While some materials are truly useful for soundproofing, others are of questionable benefit to homeowners and businesses. Here are some of the best soundproofing materials you should consider:

  • Acoustic Foam or Studio Form– These materials are distinctively wedged or pyramid shaped and are effective for absorbing sound. They are usually attached to walls as panels, hung from ceilings as baffles, or placed in corners as bass traps.
  • Acoustic Coatings– Acoustic coatings are dense rubber-like materials used as a sound barrier in cars, machines, other appliances, and as an underlayment. A perfect example of Acoustic coatings is Mass Loaded Vinyl (MLV).
  • Floor Underlayment– This is a soundproofing material used to reduce noise transmission in a hardwood or tile floor. Common examples of floor underlayment include: cork, felt, and polymers.
  • Architectural Soundproofing– Includes all forms of soundproofing used in the structure of a building. These can include soundproof windows and doors, soundproof walls, and decoupling materials.
  • Sound Insulation– These are sound insulation batts, usually made of fiberglass, mineral wool, or rock wool. The batts are designed to fit snugly between the studs of walls, and in the process, they take up airspace that can transmit sound.
  • Acoustic Fabrics– These materials are made from thick and heavy fabric, and can be used as studio blankets, theater curtains, or blackout curtains.
  • Acoustic Panels/Boards– These products come in different appealing colors, patterns, and fabrics.

Other examples of soundproofing materials include Polyurethane foams, Epoxy, Green glue, Polyester fiber, Silicone, RSIC-1 Clips (resilient sound isolation clips), Sound-break XP (soundproof sheetrock), and many more.

What Are The Advantages of Using Soundproofing Materials?

Along with minimizing the transfer of unwanted noises, soundproofing materials offer the following benefits:

  • Improved acoustics by reducing sound reverberation
  • Easy to install
  • Durable with long-lasting results
  • Improve aesthetics of a room
  • They are relatively affordable
  • Available in an assortment of patterns, styles, and colors
  • Some soundproofing materials also provide termal insulation. They help in controlling room temperatures by keeping spaces cooler in the summer and warmer in the winter

After looking at soundproofing, let’s dive into the topic of sound absorption.

What is Sound Absorption?

Sound absorption is the process in which sound is soaked up or absorbed by certain types of materials. Materials which have the abilities to absorb sound are commonly known as sound absorption materials, acoustical materials, sound absorbers, or sound diffusers.

Where is Sound Absorption Used?

The common examples of places where sound absorption is applied include:

  • Theatre rooms
  • cinemas
  • TV/Radio studios
  • Computer rooms
  • Gymnasiums
  • Concert venues
  • Auditoriums
  • Call centers
  • Conference rooms
  • Recording studios
  • Workshop
  • Arenas
  • Study rooms
  • Dog kennels
  • Sports halls
  • As aircraft engine liners
  • In the combustion chambers for rocket engines

Sound absorbers have the following properties:

  • Sound Absorption materials are more porous
  • Made of fibrous materials
  • Have open-celled structure
  • Sound absorbing materials have different shapes and surfaces i.e. pyramid surface, peaks and valleys
  • Soft and lightweight materials

How Does Sound Absorption Work?

Rather than reflecting noise, sound absorption works by converting/transforming sound energy into another form of energy such as heat, mechanical, or deformation.

What Are the Different Types of Sound Absorption Materials?

There are different types of sound absorption materials. It important to note that the ability of these materials to absorb unwanted sound highly depends on the following factors:

  • Frequency
  • Material composition
  • The thickness of the material, and
  • The method of mounting

These are the three categories of sound absorption materials:

1. Porous or fibrous sound absorbers

These materials are usually soft, porous, elastic, permeable, and not very dense. Porous absorbers absorb noise through deformation and vibration of the air.

A common example of these materials includes:

  • Insulation blankets
  • Mineral wool
  • Carpets
  • Certain forms of foam plastic
  • Fiber-boards

2. Membrane/Plate Absorbers

Plate absorbers are air impervious, non-rigid, non-porous materials that are usually fixed over airspace. The vibration of the absorber is converted into mechanical energy in the springs attached to them.

These are common examples of membrane absorbers:

  • Wood or hardboard paneling
  • Suspended plaster ceilings,
  • Windows
  • Gypsum boards
  • Wood doors
  • Wood floors

3. Resonate/Resonance Absorbers

Resonate absorbers work in the same way as membrane absorbers. However, these materials focus on issues related to bass frequencies.

Examples of resonating absorbers:

  • Layers of perforated plasterboards
  • perforated metal corrugated sheets

Which Products Can I Use to Absorb Sound At Home?

Some sound-absorbing materials can be used to add aesthetic along with performing sound absorption. Here is a list of some of the practical materials you can use at home:

  • Cushions and Pillows
  • Wall Hangings
  • Carpets and Area Rugs
  • Curtains and Blankets

Advantages of Sound Absorption Materials

In addition to improving sound quality within a space,cvyou’ll enjoy the following benefits:

  • Some sound absorbers are highly customizable for a fun look
  • Easy to install
  • Some materials are washable
  • Budget-friendly
  • Sound absorbers are easy to cut and trim
  • Safe to use and environmentally-friendly
  • Highly durable, water-resistant material
  • Flame or chemical resistance
  • Strong resistance against fungi, mold, or mildew
  • Almost all sound absorbers meet building codes
  • Sound absorption materials are available in different fabric options to match any décor

Important Factors for a Soundproofing or Sound Absorption project

Here are the important tips to utilize:

  • Identify the type of noise you want to control. Identifying this will help you choose the right options.
  • Select the method that will meet your needs in terms of budget, time and workload.
  • The size of your project. Soundproofing is ideal for big projects, especially during construction and renovation.
  • What look do you want? Pick the right products that will fit well in the space you’re trying to improve.

Final Thoughts on Soundproofing Vs. Sound Absorption

Hopefully, this article has helped you learn the difference between soundproofing and sound absorption. In summary, soundproofing blocks sound, whilst sound absorption absorbs sound.

With that said, you should now be able to embark on your soundproofing or sound absorption project with greater confidence. Feel free to browse other articles on the website to find the best project guides (like how to soundproof a door) and the best products and materials for the job.

Sources:

Luka Baron

Soundproof expert and a staunch opponent of noise. This website is a free source of information on how to 'keep it down a notch'. I update the content regularly to keep up with advancements in the soundproofing industry.

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