Silence is a material.

Acoustics is addressed at the end of many projects. When the walls are up, the floor is laid and the furniture is arriving. Then it becomes apparent that the room echoes. Then it gets retrofitted. With visible panels that were never part of the design.

This is avoidable.

What acoustics actually is.

Acoustics describes how sound behaves in a room. How long it reverberates, how it is reflected, how it is absorbed. This depends on the surfaces. On the geometry. On the materials.

Hard, smooth surfaces such as concrete, glass or natural stone reflect sound. Soft, porous surfaces such as textiles, wood wool or specialist acoustic plasters absorb it. Most rooms combine both. The question is in what ratio.

Reverberation time.

The most important value in room acoustics is the reverberation time. It measures how long sound remains in a room after the source has gone silent. For a living room the ideal values are 0.4 to 0.6 seconds. For a restaurant 0.6 to 0.9. For a concert hall, depending on the music, 1.5 to 2.2.

When the reverberation time is too high, speech becomes unintelligible. Voices overlap. The effort of listening increases. In hotels this leads to poor reviews, without guests being able to identify the cause.

How to account for it in the design.

Three approaches that have proven themselves in practice.

First: plan soft surfaces before they become necessary. Curtains, rugs, upholstered furniture. They are rarely neutral in the design, but they work doubly: functionally and aesthetically.

Second: specialist acoustic materials as part of the architecture. Acoustic plasters, perforated wood panels, micro-perforated fabric cladding. They can be integrated without being recognisable as acoustic solutions.

Third: use geometry. Non-parallel walls, vaulted ceilings, offsets. They scatter sound rather than reflecting it directly back. This reduces echo effects without additional materials.

What we see in our libraries.

In the sample rooms we digitise, we often find a gap between visual material variety and acoustic information. Fabrics are catalogued by colour, weave, care instructions. But rarely by sound absorption class. Wood panels by surface, grain, fixing. But rarely by perforation and acoustic effect.

This information exists with the manufacturer. It is rarely passed on because it is rarely asked for. Those who incorporate acoustics early in the design request this information and document it. Then it is available for the next project.