Exploring the role of sound absorption and diffusion in architectural design

Imagine sound like a pinball—ricocheting off surfaces until it gradually loses energy. In an untreated room, sound waves can continue to bounce for a long time, creating an overwhelming auditory experience that strains the ears and makes communication difficult. Acoustic treatment helps manage this by either absorbing the sound (halting its path) or diffusing it (scattering it), ultimately reducing noise and enhancing the space’s usability.

Why absorption and diffusion matter

“Sound absorption and diffusion are both critical factors to consider when designing a space. Absorption and diffusion impact how sound behaves within an area, affecting everything from speech clarity to overall comfort,” says Autex Acoustics® technical advisor, Jack Soffe.

To create a space that feels acoustically balanced, both absorption and diffusion must be thoughtfully integrated.

“Ignoring the impact of either absorption or diffusion will result in a space that is too “live” (echoey, like inside a bathroom) or too “dead” (flat and unnatural),” Jack explains. “To achieve great room acoustics you need to use a combination of sound absorbers and sound diffusers.”

The mechanics behind absorption and diffusion

Sound moves in waves, and the frequency of these waves determines their length, from long, low-frequency bass waves to short, high-frequency treble waves. For a material to absorb sound effectively, it must be thick enough to interrupt the wave’s cycle. This is why bass traps and other low-frequency absorbers are often bulky—they need to counteract the longer waveforms.

Absorption reduces the number of sound reflections, minimising echo and reverberation, and making it easier to focus on the original sound source. Diffusion, on the other hand, doesn’t stop the sound—it redirects it. By scattering sound waves in various directions, diffusers help distribute sound more evenly, softening harsh reflections and creating a more natural acoustic environment.

Acoustic design may vary depending on the purpose of a space—while performance venues like concert halls are designed to maintain a lively, resonant sound, environments such as classrooms and offices focus on speech clarity and minimising background noise. Regardless of the setting, achieving optimal acoustics relies on a thoughtful balance of both absorption and diffusion tailored to the room’s specific needs.

Always consult an expert

To ensure your space performs acoustically, it’s essential to involve a professional.

“With years of knowledge and experience, an acoustic design expert knows when and where to place absorbers and diffusers to achieve the right level of sound control for the needs of your space,” Jack says. “Acoustic design should always be considered early in the project so any acoustic issues can be tackled at the beginning, avoiding costly retrofits.”

If you’re considering acoustic treatment for your space, reach out to our team of specialists. We’ll help you find the right solution to meet your project’s unique needs.