Absorption vs. Diffusion

Absorption vs. Diffusion

As history has given us many beautiful architectural wonders, so has the growth and understanding of acoustic treatment. Acoustical concepts have transformed public spaces, manipulating sound through different materials, geometric shapes and vocal projection. As the process has evolved, we can provide better sound quality, clarity and focus through two principal acoustic tools — absorption and diffusion. While these techniques are used for the same goal, they have different methods of application. Understanding the differences between the two is critical to optimizing your space. 

Both tools will improve sound perception in spaces that would otherwise reduce sound quality if left untreated. However, the wrong choice can be unhelpful in solving the acoustic issues at play. Through guidance and testing, you can achieve the right balance, and create a dynamic space that is ideal for your intended application. 

Understanding Absorption

Sound absorption reduces sound energy in a reflective space. This is done by converting sound energy into small amounts of heat within absorptive materials, and the result is that the waves are not reflected back into the area. The opposite of absorptive materials are defined as being reflective, and can be useful to apply in certain applications whenever a space lacks acoustic energy.  The need for reflective materials to improve acoustics in a room is a rarity, but can be assessed by an acoustics engineer if it is needed in a specific space.

The right choice of absorbent materials creates a suitable environment for places like conference rooms, classrooms, houses of worship, recording studios, theaters, and concert venues by reducing the reverberation time and improving speech intelligibility. You can transform the sound of a space with different absorptive materials. A short reverberation time can add listening clarity, while a longer one adds warmth and depth. 

Some commonly used materials for absorption panels include acoustic foam, insulation wool, cork, fiberglass and acoustical fabric. 

Understanding Diffusion

Unlike absorption, diffusion aims to scatter the sound waves in different directions. Sound diffusers spread out the energy in a room to improve the even nature of different areas in the room.  As a room is diffused properly, it will help to ensure that all individuals in their own listening locations will receive the same amount of energy as other individuals. Reflective tiles or panels have uneven surfaces to disperse the sound energy. Depending on your objectives, you can choose from multiple build materials such as wood, fiberglass or plastic. The uneven surface manipulates the sound waves which would have previously reflected in one direction, and spreads them out to eliminate dead areas in that space. This even distribution of sounds creates a more immersive and balanced environment. 

Various types of diffusers exist on the market. Each works differently to scatter the sound vibrations. Some common examples include: 

  • Skyline diffusers: These diffusers are constructed from a collection of wooden blocks at various heights to reflect sound waves at different intervals, projecting them evenly across and area. 
  • Pyramid diffusers: This type of diffuser consists of pyramids with uneven sides, scattering sound around a space and handling complex audio challenges like flutter echo and standing waves. 
  • Quadratic residue diffusers: These open-faced boxes have multiple troughs at different depths based on prime numbers. This option handles sound at different frequencies, scattering sound in a predictable way. You can also choose a 2D quadratic residue diffuser to spread sound vertically and horizontally. 
  • Barrel diffusers: These diffusers resemble barrels cut in half and reflect sound in a 90-degree arc.



Absorption vs. Diffusion

When to Use Absorption

While diffusion can amplify the acoustic experience, absorption can reduce the clutter. Absorbing sound waves before they bounce aimlessly around a space can make speech more intelligible, improve music clarity, and make the overall environment comfortable. They’re ideal for any situation where reverberation is a concern, such as large rooms with high ceilings and hard construction surfaces. 

If you’ve ever been in a crowded space where you struggle to hear the people around you, this would be a prime option for absorption panels. Areas that would benefit from sound absorption include lecture halls, restaurants, conference rooms, and worship centers. 

When to Use Diffusion

Diffusion is the primary choice for any environment where you want to make sound more natural and consistent throughout a room. Flat walls and symmetrical spaces create imperfect sounds that do not occur in nature. When the correct type of diffuser is deployed, echoes and excess reverberations are reduced while enhancing the environment’s natural qualities.

Recording studios, theaters, houses of worship, and media rooms are excellent examples of environments that benefit from diffusion. 

The Art of Acoustic Design: Striking a Balance

While absorption and diffusion are different, they compliment each other and have their place in acoustical treatment. As the characteristics of a room dictate how sound waves act within the space, you must consider the size, shape, and surface arrangements to find the best acoustic treatment for the specific situation. Striking the perfect balance between reflective and absorptive surfaces is the key to enhancing sound quality. 

Whether you want sound clarity, isolation, reverberation or any other acoustic property, you can combine absorptive and diffusing options to enrich the experience. Strategically placing acoustic materials in a space will prevent sound waves from bouncing off hard surfaces and building up in areas of the room. Some materials absorb high-frequency sounds better, while others are best for low frequencies like heavy bass. 

You can also place diffusers in the room to prevent sound waves from grouping in certain areas, eliminating hot spots and dead zones. Diffusers are standard in larger spaces, but a skilled professional can leverage the technique in smaller areas, making them sound more extensive and more immersive. Understanding how sound moves in your intended space is critical to achieving equilibrium. 

Technological Advancements in Acoustic Treatment

Acoustic treatments constantly evolve, giving space more dimension and enhancing your desired sound. Manufacturers are constantly creating innovative absorption materials to reduce sound energy. The demand for eco-friendly solutions has also sparked the exploration of sustainable sound absorption materials such as hemp, flax and recycled products. 

Innovative technologies are also changing the face of sound engineering. Some solutions can be adjusted to suit the needs and preferences of a space and the technicians that work in those scenarios. Active acoustics use sensors, speakers, and microphones to monitor the sound levels and modify the area to achieve the ideal balance. 

Technology is revolutionizing the future of acoustic design. Audio, visuals and lighting are merging into one integrated solution, and we can change the layout of a space to accommodate different applications with the push of a button. A skilled engineer can transform a room with expertise and innovation. 

Choosing the Right Solution for Your Space

There are several factors to consider when choosing the right balance of absorption and diffusion, including: 

Size and surface of the room: The characteristics of the space will decide your approach, and a combination of hard and soft surfaces will affect the movement of sound waves. Balancing different textures and materials can provide the optimal acoustics in your space. 

Intended purpose: Consider what you want to achieve from the space. Your needs will differ depending on how you plan to use the room. For example, your approach to enhance casual conversation will be entirely different from your strategy in a controlled recording studio. 

Properly designed absorption or diffusion engineering should be enough to achieve your acoustic goals when working with professional designers and proper planning for your given uses. In most cases, a combination of absorption and diffusion works to create the best results. Placement is just as important as material selection, and many variables must be considered. Acoustical engineering is complex and consulting experienced professionals is your best chance to maximize your space. 

Improve Your Acoustics With Illuminated Integration

With the right approach and professional input, you can take almost any space and create the environment you want. Illuminated Integration offers various acoustic services, from acoustic testing, material selection, environment design, room visualization, and direct audio coverage for absorption and diffusion.  Let us help you turn your room into your desired environment.

Contact us to learn more about how we can transform your space today. 

Absorption vs. Diffusion
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