The trinity of acoustics

Sound propagates more easily in timber structures than in heavier materials. However, it does not mean that all timber buildings have poor acoustics. According to acoustician Alain Bradette, proper design is the key to success.

The main challenge with acoustics and timber is that, despite its large dimensions, wood is a lightweight material. Compared to concrete, we cannot simply consider direct sound transmission through a wall; we must think about all the paths through which sound can propagate. This requires different design methods.

“In a typical construction, you can address sound insulation by designing in 2D, but in timber projects, we have to constantly design in 3D. It is more complex and technically challenging, but also more exciting,” says Alain.

Alain has been working in acoustics for 25 years in Canada, Norway, and France, so he knows what he’s talking about.

“To find good solutions, acoustics should be included early in the process. Acoustics is a specialized field that intersects with many other disciplines, and the solutions interact with each other. I believe we should combine multiple functions in a single approach. This requires close collaboration between acoustics, fire safety, and structural engineering—I call it the «trinity.» At Sweco, we have a strong expertise in mass timber, both technically and in terms of collaboration, and that is crucial for success”, says Alain.

With strong teams, it becomes easier to design efficiently, which is essential in a changing market.

“The trend is that clients want to invest less in the design phase, which means we have to reduce the number of alternatives. Previously, we would consider up to five alternatives, but now we evaluate a maximum of two. We can do this thanks to our accumulated experience. It doesn’t mean we are simply copying what we’ve done before; it means we immediately know which alternatives to develop further. You could call it efficient ‘tailoring’”, says Alain.

The high competence within the teams is the result of working on various projects over a long period.

“We can’t pre-calculate everything; we have to calculate and then test a solution. Little by little, we gain experience that we carry forward, enabling us to efficiently tackle new ambitious timber buildings”, says Alain.