Understanding the importance of sound absorption and diffusion in building design

In rooms that lack acoustic treatment, this ‘bouncing’ can last a long time, causing undue stress on the ears and, ultimately, making it very difficult to hear. By ‘treating’ a room, the energy of the sound wave is either absorbed (stopping the bounce) or diffused (scattering the bounce) to reduce ‘noise’ and create a more comfortable, functional environment.

The importance of absorption and diffusion

 

“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.

 

Absorption and diffusion go hand in hand, and should be considered equally to ensure your space feels natural.

 

“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.”

 

How does absorption and diffusion work?

 

Sound travels through space in waveform. The length of the wave is determined by the frequency of the sound, which varies on a spectrum of low (bass) to high (treble). To absorb sound, your material must be thicker than the length of the sound wave cycle to stop the wave from continuing its journey. Low frequency sounds have a longer wave cycle than high frequency sounds, which is why sound absorption materials designed to absorb bass are so thick. Absorbing sound reduces reflections (the aforementioned bounces), also known as echo and reverberation, making it easier to hear and understand sound coming from the original source.

 

Alternatively, rather than absorbing the sound wave, diffusers split and scatter the wave in multiple directions. Scattering the wave softens the reflections, resulting in a more balanced and nuanced distribution.

 

Some environments, like auditoriums, or concert halls are designed to control and maintain the ‘liveliness’ of sound to ensure a good listening experience; other spaces, like classrooms and meeting rooms, focus more on speech clarity by reducing background noise and echo. Both spaces will use sound absorbers and diffusers in their design, but the ratio of absorption to diffusion will be determined by the room requirements.

Always work with an expert

 

To design a room for success, it is crucial to work with an acoustics expert.

 

“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.”

 

Do you need acoustic treatment in your space? Get in touch with our team of acoustic experts today for solutions designed to meet the unique requirements of your project.