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  • Charlotte Haye

The Difference Between Sound Insulation And Sound Absorption

Updated: Jan 5, 2023

Whether you’re planning a new building or just refurbishing an office, you will probably have

thought about sound at some point. It’s a key part of the planning process, and an important step to ensure the safety and comfort of both the people in your building and around it. You might have even looked into ways of preventing noise travelling and come across the phrases ‘sound insulation’ and ‘sound absorption’. On the surface, you might think they do the same thing – but that’s where you’re wrong, and we thought we would explain the difference today.

What Is Sound Insulation?

Sound insulation (often called soundproofing) can be equated (ish) to thermal insulation –

keeping sound ‘in’, much like we try to do with heat. As with thermal insulation, some sound

will always get out, but the aim is to minimise sound transfer. It’s also sometimes called

sound isolation, because it isolates the sound within a specific space. Whichever term you

use, it’s all about blocking noise.

Think of it like a music rehearsal studio – if you have 3 rooms, each with a different band in

it, the last thing you want is to be able to hear all 3 bands at once while you’re in the

reception area. So you soundproof each rehearsal room so that the sounds made inside stay inside, and don’t travel out into the rest of the building unless you open the door. It’s very difficult to get a soundproofing solution that’s 100% effective (i.e. that no sound whatsoever is heard outside the space), but most can get you pretty close.

Soundproofing can be done in a number of different ways, depending on how thorough you

need the soundproofing to be. Resealing doors and windows, having blown-in insulation in

the walls, hanging baffles introducing soft furnishings and even moving dense furniture to

strategic places are all popular methods of soundproofing. Some are more effective than

others, and the cost ranges from thousands to virtually nothing.

So How Is Sound Absorption Different?

Sound absorption (often called acoustic treatment) is still focused on sound within a space – but in this case, it’s about the quality of that sound. Acoustic treatments are designed to

change the dynamics of how sound waves move within the space, giving listeners a cleaner

and ‘truer’ listening experience.

The main issues acoustic treatments tend to address are reverberation and echo control.

Mitigating peaks and nulls in a room’s frequency response, minimising flutter echo, comb

filtering, and preventing modal ringing at low frequencies. All of this helps reduce sound

interference that can be distracting or harmful during listening.

Acoustic treatments are normally done using a mix of absorption and diffusion. This

combination reduces the acoustic energy in room and absorbs any sounds that would

normally bounce around for a while. This makes it easier to concentrate, as there are no

distracting background sounds, which is why offices and schools – or any place that you

need to focus. Acoustic treatments are also used in music venues and cinemas since they can drastically improve the listening experience by removing sound reflections and making

music cleaner to the ear.

Think about a bouncy ball bouncing round a room – the more ‘absorptive’ (e.g. softer) the

surface finishes, the more energy gets absorbed with each impact and the less the ball will

bounce around the room. The more reflective the surfaces (usually hard surfaces), the

longer the ball and sound will bounce around the room.

Which Do I Need?

When deciding between soundproofing and acoustic treatments, it’s best to look at the use

of the space and the surrounding area. If you need to improve sound performance within a

space but don’t need to protect the outside world from it (particularly if the activities you’re

doing aren’t too loud), then you will probably only need to consider sound absorption.

Remember that sound insulation can often be added on top if you need it, and on many

projects, sound insulation and sound absorption are done together.

At Auricl we work with architects and building firms to ensure sound insulation and sound

absorption are considered in their designs from day one. This could mean working on plans

to ensure the architecture of the building creates a healthy acoustic environment or providing surveys to support the retrofitting of sound treatments. If you would like to know more, just get in touch with us today.

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