Providing audio for open spaces

Paul Mac examines the evolving world of open-plan offices and how best to make these reinvented spaces into comfortable, flexible experiences for everyone.

While the open- plan office is nothing new, in recent times the habits of its native populations have changed beyond all recognition.

Hybrid working patterns, agile teams, huddles, smart boards, and lots more besides have all changed the modern open working space from a labyrinth of shuttered workspaces to a much more complex affair.

So audio in an open office space is not just an acoustic problem - it’s a people- problem too. Wellness is recognised throughout corporate land as a boon to staff retention, effectiveness, happiness, and more. If your employees are happy, they can be inspired to do great things. If they are annoyed because Bob in Planks stands and hollers down his headset like he’s actually trying to shout all the way to Building B, or they have a headache because every teaspoon clink or keyboard tap reverberates until lunch time, a mutiny could be imminent.

Privacy at a workspace is one of the most fundamental pieces in this jigsaw, and it’s not simply a problem of keeping secrets. We all have the innate ability to tune into ambient speech and focus on one voice in the background. Understanding what’s being said three desks down is the ultimate distraction. In this case, intelligibility is the enemy - a difficult thing to admit in an audio discussion. A general low-level of unintelligible rhubarb is far more acceptable than discrete, intelligible voices.

But then, at the other end of the office around the big round table that marketing uses for its daily huddles, everyone has to hear everyone clearly.

Person people
These two examples show that an office space has to be a mixture of solutions. Noise levels have to be controlled, acoustic quality has to make the room invisible, and everybody has to be happy.

Eddy Bøgh Brixen is a consultant (EBB Consult), an Associate Professor at the Danish National School of Performing Arts, a Professor Bøgh Brixen at Central European Studies of Music and Acoustics who cut his teeth with the Danish Broadcasting Corporation: “Before you consider all of the electro acoustic systems,” he notes. “You have to consider that this is all about people. You have to decide how to deal with the people in that space when you are planning systems. That’s something often not taken seriously enough, you could say.”

The other side of the people equation is the customer - the company, the buildings manager, the IT department, even the people team. Some or all of these stakeholders might have a say in how a space comes together, what teams go where, the atmosphere, or the culture they want to promote. Audio has a part to play; communication is crucial.

Mark Kempson is the head of consultancy and design with systems integrator Kinly, he knows how valuable the client relationship is when it comes to a successful environment. “We try to build strong relationships with our clients so it’s not just a transactional thing. We work with the various departments, we work in partnership with most of our larger clients. There is a big benefit there for the end result.”

Standard practice
A good place to start in understanding issues and solutions is to look to standards and certifications that already exist. The ISO 22955:2021 Acoustic Quality of Open Offices is a relatively recent document that re- examines the issues from the point of view of use cases packaged into six ‘Space types’. The document focuses on containing speech propagation and as such is a fantastic resource for looking at acoustics, layout, furniture types, measurement, and more.

Another set of documents and criteria that could be useful - or even required, depending on your client and your geography, are the LEED (Leadership in Energy and Environmental Design) and WELL (WELL Building Standard) provisions. Both are US-based accreditation schemes concerned with building design, though the former concentrates on sustainability and the latter concentrates on the wellness of the people that use the building. In the WELL scheme, for instance, points can be gained specifically for using sound masking technologies in an open office environment.

There are, in fact, currently 18 points available towards accreditation in the audio section alone, reflecting a welcome emphasis on the issues, and recognising that sound is one of the most conspicuous points of dissatisfaction in studies around office working.

The acoustic’s the thing
After people, there’s acoustics. Bøgh Brixen makes it clear that in his view, nothing matters more than getting that right first.

“The acoustics are very important. If you don’t care about the acoustics you can forget everything about electroacoustic or any other audio solution.” He says that one important criteria is a concept known as ‘acoustic capacity’: “If you have a room with a certain type of acoustic you can calculate how many people can be in that room before they start to raise their voices. Sometimes you’ll go to a restaurant where they’ve spent all the money on decorations but nothing on acoustics. You’ll go once, but never return.”

In that case, the likelihood is that the restaurant has exceeded its acoustic capacity and the Lombard effect - the tendency for people to raise their voices with raised ambient noise levels - is making the environment very uncomfortable.

The most direct solutions to this issue (and therefore to increasing the acoustic capacity) are adjustments in reverberation time and people- spacing. In a restaurant this is mostly space between tables, but in an office this might be space between team areas or activity areas and so on.

Absorption is of course the main route to reducing reverb time, though here Bøgh Brixen warns that too often the cheaper route to high frequency absorption is probably money wasted: “Whatever you do, you have to make sure the acoustics work all the way down,” he says. “I normally include the 63Hz octave band when I do measurements and treatments. Very often it’s concrete construction behind the interior surfaces, and if it’s not treated properly it causes low frequency booming sound that can be very tiring.

“Also, an untreated ceiling is a common problem in offices. However, some types of absorbers like the perforated plates can have a reflective effect depending on the height of the source.” That is, the sound of a person seated and talking hits a ceiling plate at a much better angle than speech from someone standing up. That shallower angle can end up being reflected by the treatment rather than absorbed.

Screens can be effective and are a common way to divide a space up and create more comfortable areas for individuals. Though even with this strategy, care needs to be taken. First, screens need to be high enough to block direct sound, which in turn would tend to block sight lines. Also, the proliferation of adjustable or standing desks means that screens need to move with the desk height. In some cases, screens can even cause people to talk louder, which can negate the screen itself.

Going electric
The full range of electroacoustic strategies available to an integrator is enormous, and ranges from simply giving employees upgraded headsets, to the full might of something like the Meyer Constellation system. While these could come under the ‘treatment’ category, there’s a whole tech space that is rapidly developing and is revolutionising office spaces using array principles, such as the new generation of sound bars, and the Sennheiser TeamConnect range, which includes the TeamConnect Ceiling mic with beamforming tech.

At the simple end, Bøgh Brixen has found voice feedback features in headsets very effective. “They have feedback of your own voice into the headphones,” he explains. “If you speak too loudly, you get a higher level of your own voice in your ears and you’ll lower your voice. It’s a kind of active noise control.”

image: stockfour/


Bøgh Brixen also mentions the various traffic light-style audio metering indicators that are available. These work simply as a visual prod, letting employees know noise levels are too high and that they should lower their volume. A caveat here is that this needs willing buy-in from the employees, otherwise it has the potential to be labelled as a ‘nannying’ device, producing an altogether different response.

The second use for these is as a monitoring device to inform ongoing development of a working space. If you know that a particular team works loudly, they can be moved further from the quiet ones.

The mask
Sound masking is relatively common in the US, maybe not so much in the UK and Europe, though that’s not necessarily how things will stay. If you’re not sure, this is a system that pushes noise with a particular profile into a space in order to mask speech sounds. The result should be that speech from neighbouring desks becomes unintelligible, privacy goes up, and the environment becomes more comfortable. Bøgh Brixen notes that correct level is crucial here as a badly calibrated masking system can have an opposite effect, causing headaches and raised speech levels as people instinctively raise their level above the ambient.

Masking though, can be a perfect fit. For Kempson at Kinly, fitting out a communal office space is a common challenge - the type of office where individuals can rent space or use it as a walk-in office. Here, privacy isn’t just about noise levels and comfort, it actually is about privacy. “The problem there is that you have multiple companies talking on the same floor, so we’ve standardised on the masking solution in that case. Otherwise it’s not something that we’re typically asked for. The majority of requests for that kind of system are for background audio, and that’s mostly driven by a desire to create a better environment.

“Another area we have seen more happening is where customers have wanted to do conferencing on open plan floors. That’s not something we would have considered until recently without some kind of soft booth screening. But what video bar and sound bar manufacturers have managed to achieve with directionality, has made this a serious option.”

One such manufacturer is Sennheiser, with its impressive TeamConnect technology using beamforming microphones that can ‘select’ participants, amongst other things. Jens Werner is product manager for business communication at Sennheiser and sees new and developing technologies as a game-changer for corporate spaces: “I visited a large architects’ office in California in a huge industrial space. They have created collaboration zones and various areas around those offices for meeting with each other and with external participants. They have installed our beam-forming microphone array alongside highly directional loudspeakers and show it’s now possible to create a virtual meeting room space within an open office space.”

The big idea is to make the technology disappear - let people trust the microphone to work its magic so the temptation to raise voices to reach a screen or other people goes away.

To complement the larger ceiling microphones, and the TC Bar sound bars, Sennheiser has just announced the TeamConnect Intelligent Speaker - a small desk mounted device that combines the TeamConnect beamforming microphones, Microsoft Cortana voice intelligence, and real time transcription, and the ability to recognise ten different participant voices. It works exclusively with Microsoft Teams. It’s a development that could provide another leap - with clients gaining more understanding of what’s possible, so they can adjust their ambitions accordingly.

Finally, we have to give a shout out to the network. It’s something that has made a massive difference to the budget considerations of large office projects. Kempson; “Those systems were prohibitive on cost for most clients until only a few years ago. We used to have to run 100V line systems with dedicated amplifiers in comms room racks and so on. It was a massive challenge.

“Dante has opened the market up for us, most often we’re working on retrofits and with open ceilings it’s a massive challenge to run new cable infrastructure. Now, where there's a data outlet you can offer a solution with a much more reasonable fee, and it sounds better, and you’ve got flexibility.”

Home time
There’s no doubt that office spaces and their use cases have evolved massively over the last few years. Just as the development of remote working technology went into overdrive through the Covid era, so have the expectations of employees and employers around their collaborative real estate and the value it has to generate. Company culture increasingly revolves around hybrid working practices and offices that can be for business, for social, for office-based employees, and for remote employees. They need every desk to work for several different people, every area to work for several different teams.

Great audio can be a hugely significant contributor to worker  wellbeing, even though the main measure of success is how inconspicuous its contribution is. It’s also an area where audio technology is still making strides and where new possibilities are opening up right now.

Remember, it’s a people- driven challenge, and you can’t go far wrong. 

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