Improving Office Acoustics: Causes, Standards, and Effective Measures

Key points at a glance: 

Anyone wishing to improve the acoustics in their office should not start with the product catalogue, but with a measurement. Poor room acoustics is not a matter of taste, but a measurable condition with standardised target values. It has the greatest impact where people are speaking – and in such situations, sound attenuation alone does not solve the problem: it is only the combination of structural absorption and carefully selected audio technology that makes speech intelligible.

- The order in which you should proceed

- What DIN 18041 and ASR A3.7 actually require

- How reverberation time is measured and assessed

- Why microphone placement, DSP and calibration are decisive for the outcome

- Where acoustics matter outside the office: showrooms, brand spaces and retail

Even the best conference technology is of no use if the room’s acoustics aren’t up to scratch. A microphone picks up everything that happens in the room – and in a reverberant room, that’s not just the voice, but every reflection of it too. That’s why office acoustics aren’t just another facility management issue alongside lighting and indoor climate, but the very foundation.

Quick question, quick answer:

How can I tell if the office acoustics are poor? You can tell because conversations can be heard clearly from several metres away and rooms sound echoey.

Are there any guidelines for this? Yes. DIN 18041 regulates audibility in rooms, whilst workplace regulation ASR A3.7 covers noise protection in the workplace.

What is reverberation time? It is the time it takes for a sound event in a room to decay by 60 decibels. It is the key measurement for room acoustics.

Are acoustic panels enough? They are an important part of the solution, but not the whole answer. In rooms used for video conferencing, the electroacoustic aspect also comes into play.

Would you like to know how your rooms are performing? We’ll assess the current situation and provide you with an evaluation. Enquire without obligation →

Causes: Construction methods, materials and use of space

The cause of poor office acoustics almost never lies in people’s behaviour, but rather in the construction methods used. Modern office spaces are built using materials that reflect sound rather than absorbing it: exposed concrete, glass surfaces, screed, and smooth furniture surfaces. There are good reasons for this choice – design, cleaning, fire safety, cost-effectiveness – but from an acoustic point of view, it is the worst possible combination.

The second cause is the floor plan. Whereas in a cubicle-style office a wall would separate two conversations, in an open-plan space there is nothing to separate them. For open-plan office acoustics, this means that speech remains intelligible over long distances, and that is precisely what makes it disruptive. Noise in the office is therefore rarely loud in the strict sense – the brain simply cannot block out intelligible speech.

The third cause is most frequently overlooked: rooms are now used differently from how they were intended when built. A meeting room that was designed for people to be physically present has now become a video-conferencing room. The demands on speech intelligibility have thus increased significantly, even though the room itself has not changed. The article on setting up conference rooms highlights other typical planning mistakes in this context.

Improving office acoustics: the approach that works

The good news is that room acoustics is one of the few topics that can be assessed entirely objectively. There is a measured value, a standard target value and a calculable path between the two. Anyone wishing to improve office acoustics is therefore best advised to proceed in five steps:

1. Measure. Record. 
the reverberation time whilst the room is in use, across all relevant frequency bands.

2. Evaluate. Compare. 
the measured value against the target values set out in DIN 18041 and quantify the action required.

3. Add structural absorption. Supplement any 
missing absorption surfaces – first on the ceiling, then on the walls.

4. Electroacoustic tuning. 
In rooms used for video conferencing, calibrate the microphone placement, signal processing and sound reinforcement to suit the room.

5. Re-measure. 
Check whether the target value has been achieved, rather than relying on your impression.

The most common mistake lies in the first two steps: they are often skipped. Absorbers are then ordered because the room sounds reverberant, and afterwards nobody can say whether it was enough or whether the money was spent on the wrong frequency. The measurement costs a fraction of the cost of the work and determines its effectiveness.

Not sure where your rooms stand? We measure the current condition and classify it according to standards. Get in touch now →

The foundation: DIN 18041, reverberation time and measurement

Two sets of standards provide the benchmark. DIN 18041 deals with audibility in rooms and distinguishes between rooms intended for communication over longer distances – such as conference and classrooms – and those where the primary concern is noise reduction; for the first group, it specifies target reverberation times depending on the room volume. ASR A3.7 is the workplace regulation on noise; it sets out the specific requirements of the Workplace Ordinance and is therefore not a recommendation but the standard against which employers must be measured. Together, these two form the basis for discussions with building clients, management and the works council – often the difference between a wish and a budget.

The key parameter here is the reverberation time: the time it takes for a sound event in the room to decay by 60 decibels. The longer this time is, the more successive syllables overlap. The frequency response is crucial here – a room may appear unremarkable in the mid-range but still have excessive bass reverberation, which noticeably reduces speech intelligibility.

Measuring room acoustics usually takes less than an hour per room: a defined signal is played into the room, a calibrated measurement microphone records the decay at several positions, and the analysis provides the reverberation time across the relevant frequency bands. Measurements are taken whilst the room is in use, i.e. furnished. This reveals how much absorption area is lacking in which frequency range. SIGMA AV works with reliable acoustics firms to measure the reverberation time in the room and uses this to determine what action is required.

This lays the foundation – but it only solves half the problem. The standard specifies how long a room is permitted to reverberate. It does not specify whether a voice will be clearly audible to remote participants.

Need to assess several rooms or sites? We carry out on-site measurements and provide a prioritised list of recommended measures. Go to the contact form →

Structural measures and acoustic elements

The most effective solution is absorption, and the largest available surface area for this is the ceiling. Suspended ceiling panels, suspended absorber panels or baffles provide a large surface area without altering the floor plan. Where the ceiling is not an option – for example, for fire safety or heritage reasons – the focus shifts to wall absorbers.

It is important to select these according to frequency range. Porous absorbers, such as fleece or foam elements, are particularly effective in the mid and high frequencies and cover the speech range well. Low frequencies require different designs with greater depth – a room in which only porous elements are suspended may therefore still have excessive bass reverberation.

Added to this is screening: partition walls, tall furniture and green room dividers interrupt the direct path between two workstations. They do not replace absorption, but they do complement it. The sequence remains crucial – which acoustic elements are required and in what quantities is determined by measurement, not by the catalogue. SIGMA implements this structural aspect in collaboration with a specialist acoustics partner, who is responsible for product selection. Integration into the media technology – microphone placement, signal processing and calibration – remains, however, in our own hands. It is precisely this second half that distinguishes an AV integrator from a pure acoustics planner.

The electroacoustic side: microphone placement, DSP and calibration

Structural measures bring a room up to a good basic standard. However, as soon as people are involved, the technology in the room also plays a decisive role in determining whether speech is heard clearly.

Microphone placement is the first deciding factor. It must cover every seating position without picking up sound from the entire room. Ceiling microphones with directional characteristics focus on the area where people are speaking and suppress what is happening elsewhere – ventilation, keyboard clicks, background chatter. The more reverberant the room, the more important this focusing becomes, because a wide-range microphone will also transmit the reverberation.

Signal processing in the audio DSP takes care of the rest: it suppresses feedback, compensates for the echo from the other end of the line, reduces steady background noise and emphasises speech. A well-calibrated DSP can audibly improve a mediocre room – but it cannot replace an untreated one.

The sound system must provide even coverage throughout the room so that it is not just the front seats that can hear clearly, whilst the volume has to be turned up at the back.

The final step is the calibration. Speakers and microphones are tuned to the specific room, levels and frequency response are corrected, and microphone zones are set. This is done via the DSP’s programming and is therefore not an accessory, but rather manual work carried out on the individual room. It is only this step that turns good components into a functioning system – and it is the reason why two rooms with identical equipment can sound completely different.

The management conference room at the Steag Iqony Group demonstrates just how far this goes. There, the microphone setup is divided into zones: the system recognises which area of the table someone is speaking from and activates the corresponding camera – if no one is speaking, a wide shot of the room is shown. With up to 20 people in the room, this ensures that the right person is always in the frame. However, this interplay between speaker localisation and camera control only works if the zones record clearly and distinctly. A reverberant room blurs precisely this separation, and the automatic camera tracking begins to jump around. Acoustics and camera technology are therefore more directly linked than it might initially appear.

Architectural acoustics and electroacoustics address different aspects of the same problem: absorbers ensure that the room does not work against the technology, whilst the technology ensures that speech reaches where it is needed. Our page on AV integration shows how the two come together.

Do video conferences sound like a struggle for you? Let’s take a look at your space and technology together. Get in touch now →

Where acoustics matter outside the office: showrooms, brand spaces and retail

The same problem arises wherever people are expected to understand what is being said in designed spaces – and is usually exacerbated there, precisely because these spaces are not designed with speech intelligibility in mind.

Showrooms and brand spaces. Brand spaces thrive on glass, exposed concrete and open-plan layouts. It is precisely these materials that make any product demonstration a struggle: the presenter’s voice competes with its own reverberation, and the larger the group, the harder they have to speak to be heard. Where media installations are also running, two sound sources overlap in a space that reflects both. Our projects in this area include the Henkel Inspiration Centre Z55. The solution rarely lies in turning up the volume, but rather in directional sound reinforcement that covers the presentation area without filling the entire space with sound.

Retail. In the retail sector, two conflicting requirements come into play: music is intended to fill the space and create atmosphere, whilst announcements must be clearly audible at specific points. If both are played through the same system in the same room, the announcement is usually drowned out. The solution lies in separate zones with their own volume and tone controls, so that announcements at the till can be heard without the music in the sales area becoming louder. Our page on media technology in retail illustrates what this means in terms of equipment.

Frequently asked questions about office acoustics

Conclusion

Anyone wishing to improve the acoustics in an office should proceed in the following order: measure, classify according to standards, derive measures, implement them, and re-measure. Reverberation time turns a vague nuisance into a figure; DIN 18041 and ASR A3.7 provide the benchmark, and only then can it be determined which acoustic elements are appropriate and in what quantities.

The impact is most noticeable where people are speaking – in meeting rooms as well as in showrooms or on the shop floor. And the task does not end with absorbers: it is only through microphone placement, signal processing and calibration that speech is effectively conveyed. Each approach solves a part of the problem that the other cannot. SIGMA supports you every step of the way – from measurement through to planning structural measures with our acoustics partner, right through to AV integration and calibration. You can find further specialist articles in the Newsroom, and an overview of all our services under ‘Our Expertise’.