Improving room acoustics — and you can actually hear it.
Why rooms echo, which measures really work, and how much space you’ll need. No sales pitch.
Room acoustics can be improved in two ways: Absorb sound — soft, open-pored surfaces absorb it — and Scatter sound — Irregular surfaces break it up. Absorbers fitted to walls and ceilings are most effective; as a rule of thumb, they should cover around 20 to 30 per cent of the room’s floor area.
Why is there an echo? At all?
Every sound hits surfaces and is reflected back. The length of time it continues to echo is known as the reverberation time — and this depends almost entirely on how much of the sound is absorbed by the room. Glass, concrete, screed, plasterboard and large window areas do not absorb anything; they reflect everything back. This is precisely why modern offices, surgeries and catering premises sound harsher than older ones: open-plan layouts, smooth materials, few textiles.
The effect isn’t just a nuisance. 35 per cent of office workers complain about poor acoustics in the workplace, in rooms with at least two people, it is more than half — noise tops the list of disruptive factors in the survey, ahead even of the climate and lighting. (forsa on behalf of the Office and Working Environment Industry Association, over 1,000 respondents.)
What helps — and just a little bit
| Measure | Effect | Optics | Care | Can be retrofitted |
|---|---|---|---|---|
| Carpets & Curtains | Good for high notes, little effect on the lower registers | Unobtrusive, hardly alters the look of the room | Vacuum, clean, replace from time to time | Can be retrofitted at any time |
| Upholstered furniture | Noticeable, but only where they are standing | Part of the furnishings | Routine furniture care | At any time |
| Ceiling sails | Very effective, especially in rooms with high ceilings | Technical, visible as an acoustic element | Dusting | Must be hung up; take care with electrical fittings and sprinklers |
| Wooden slats & felt panels | Effective, depending on the structure and the manner in which it is held | From warm to technical, widespread | Dusting | Easy to retrofit |
| Moss absorber | Up to 60% sound absorption in accordance with DIN EN ISO 354 | Nature in the room — the only thing visitors take photos of | None: Dust off after five years at the earliest | Easy to retrofit, without the need for water or electricity |
Every measure has its place. If you’re renovating anyway, you can go a long way with carpets and curtains; if you want to achieve something retrospectively without altering the room, you’ll end up with absorbers on the walls and ceiling.
How much area — and what should we do with it?
Where should I put it?
Three rules that work in almost any room: Firstly, opposite the sound source — where voices travel first. Secondly, on the early reflection surfaces, i.e. the side walls between the speaker and the listener. Thirdly, from ear height upwards; below that, there’s usually furniture anyway. In rooms over three metres high, however, you should start at the ceiling, as this is the largest unused surface.
Four rooms, four starting points
Office & Open-plan office
If you want to improve the acoustics in the office, this is where you start. A typical scenario: conversations carry across the entire space, and telephone calls disturb people two rows away. An effective solution is a combination of ceiling-mounted absorbers and partitions between zones — separation where the sound is generated, and absorption where it would otherwise bounce back.
The World Office →Meeting room
It’s a common problem: the room echoes, and the other person on the video call can only make out half of what’s being said. Often, two wall surfaces at the first reflection points — opposite the speaker’s position and on the side wall — are sufficient.
View acoustic solutions →Surgery & Reception
Typical: people in the waiting room can hear what’s being said at the reception desk. Discretion is an acoustic issue here: a partition between reception and the waiting area reduces the noise level and blocks out conversations.
The World in Practice →Catering
It’s typical: once occupancy drops to half capacity, it gets noisy and guests stay for shorter periods. Large, hard surfaces are to blame — the ceiling and walls contribute most to this, as the floor is usually covered.
The World Hotel & Restaurant →What planners and users most frequently asked
How much absorber surface area do I need?
As a rule of thumb, allow for around 20 to 30 per cent of the room’s floor area to be covered by sound-absorbing surfaces. In a room up to 20 m², that amounts to 4 to 6 m²; for a room up to 35 m², it is around 8 to 10 m². Above this size, the room’s geometry comes into play — in such cases, it is worth carrying out an on-site assessment rather than relying on a formula.
Are plants enough to improve the acoustics?
Only to a limited extent. Individual pot plants scatter sound slightly, but absorb hardly any — they simply lack the surface area for that. Greenery only becomes effective when it forms a continuous, open-pored surface: such as a patch of moss on a wall or ceiling, or as a room divider.
Wall or ceiling — which comes first?
In normal-sized rooms, it’s the wall; in high-ceilinged rooms, it’s the ceiling. The decisive factor is which large, hard surface the sound is directed towards: for ceiling heights of over three metres, this is almost always the ceiling; below that, it is usually the free wall opposite the sound source.
What are the acoustic benefits of a Moss wall?
Up to 60% sound absorption in accordance with DIN EN ISO 354. Pole Moss & Bun Moss is the most effective due to their deep, cushioned structure; flat types of moss absorb less sound, but do so more evenly. The amount of sound that reaches the room also depends on the surface area and position.
Does a carpet help to reduce echo?
Yes, but only in the higher frequency range. Carpet absorbs high-pitched sounds whilst largely allowing low-pitched ones to pass through — so the typical office noise from voices and telephone calls remains partly audible. It is rarely sufficient on its own.
How quickly do you notice the difference?
Immediately after installation. Reverberation is a physical phenomenon, not something you simply get used to: as soon as the absorbent surface is in place, the room sounds different — users usually describe it as ‘quieter’, even before they realise why.
The next step
If you’d like to know how Moos works as an acoustic absorber in your room: the collection showcases the different designs, whilst our advisory service will estimate the required area and position based on your measurements. And if you’d like to feel the material for yourself first, you can order the Sample box.