Sound advice on effective noise masking for open plan offices

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For some people, the open plan office is a social paradise while for others, it’s a nightmare. We either find ourselves surrounded by a circus of distractions and at other times, deathly silences, hence the importance of noise masking in offices and facilities.

Dr Nigel Oseland, an environmental psychologist and director at Workplace Unlimited, says creating optimised office environments is increasingly challenging.

“As more companies are adopting open plan design and agile working, the core challenge to the workplace community, designers and suppliers is to resolve office noise distraction and enhance focussed work, while maintaining collaborative and creative environments,” says Oseland.

A survey recently undertaken by the Remark Group and Oseland in the UK has shown that out of 1,000 workers, 65 percent say noise impacts their ability to complete work accurately and 58 percent say that noise has a high impact on their stress levels.

It seems that what sounds good in theory is often different in practice. In theory, reducing literal walls as a way of reducing figurative walls and increasing collaboration sounds ideal. However, as the office becomes a sort of ‘bullpen’, face-to-face interactions tend to diminish. There is a great reduction in the ability to have confidential or private conversations, which often leads to anxiety and difficulty in concentration and performance.

The open-plan is reminiscent of the panopticon – an institutional building designed by philosopher Jeremy Bentham in the late 18th century. The purpose behind the design was to allow inmates of an institution to be observed by a single overseer without inmates knowing when they were being watched.

So when employees are all bundled together in a bullpen, everyone hears more than they want or need. This easily leads to a state of hyper vigilance, as the body sits in a constant state of alertness to its surroundings rather than being in deep focus on the task at hand.

Changes in Australia

Polyvox is a Sydney-based sound masking contractor which designs, supplies and installs the LogiSon Acoustic Network across facilities to optimise noise levels. The LogiSon product has been around for 40 years while Polyvox was founded two years ago amid the revisions to the AS2107.

Attila Szabo, engineer at Polyvox, says that demand for sound masking installation has increased significantly in the last two years in Australia, due to the revisions made in the Australian Standard AS2107 in 2016 (Acoustics – Recommended design sound levels and reverberation times for building interiors).

The AS2107 outlines noise levels within an internal environment. In the last edition in 2000, it only listed a maximum noise level, which led to a number of spaces being too quiet. After the revision of the Standard in 2016 to include a minimum and maximum, acoustic engineers use sound masking now to set a limit and reduce variation in noise levels.

“The idea is that the larger the range between the maximum and minimum noise levels, the more people notice the difference. If you’re working in a really quiet space, people start noticing things like tapping on a keyboard, which they otherwise normally wouldn’t. The idea behind sound masking is levelling the background noise to the Australian Standard which helps control privacy and noise within a space,” says Szabo.

How it works

A network of customisable speakers are fitted into the ceiling void of a building or across different floors. Ceiling grids with ceiling tiles require installation above the tiles, so the noise refracts off the concrete slab. On a set plasterboard ceiling, the speakers must be fitted into the plasterboard. If there’s no ceiling, then the speakers are placed pointing towards the concrete slab, where they dissipate the general noise.

“Areas that require more masking can be easily adjusted to accommodate. And in spaces which have AV (audio visual) equipment, you might choose to make it a bit quieter to help with the clarity of AV, such as in visual conferences,

“Each environment has its own frequency curve showing which noises are higher and which are lower. So it’s designed for two reasons: one, to cover up speech frequencies to allow for more privacy, and two, so your brain doesn’t receive unwanted noise. The aim is to achieve a frequency that runs on a gentle curve,” says Szabo.

Where to next?

Since the Australian Standard now includes sound masking as fundamental to an internal environment, business for acoustic engineers has significantly increased.

“The main projects that we have worked on include bank branches, because they have limitations on their building construction. For example, the steel mesh above the ceiling, which is installed for security purposes, means their walls cant run all the way up. Their partitions are usually glazed, so there’s not much control for privacy,” says Szabo.

“We’re about five years behind the acoustic industry in the UK, US and Canada, so we can see where it’s heading. All acoustic consultants incorporate sound masking as a part of their facility design now, as more people understand it and know about it.

“We can retrofit applications as well, so facility managers should get in touch with an acoustic consultant to assess the whole space or building. If it’s a large facility then I think it’s definitely an important thing to do,” says Szabo.

Other common facilities that have implemented sound masking systems across the world include call centres, financial institutions and more recently, hotels.

“This is a new space that has really been picking up this year. There is a Canadian product we have recently been distributing called Modio Guestroom Acoustic Control, which is essentially a sound masking system brought from offices into individual hotel guest rooms to help with noise between rooms,” says Szabo.

With growing awareness for sound masking across workplaces and facilities, this technology takes us a step closer towards the optimised workplace environment.


Image credit: Martin Knowles (courtesy of LogiSon)

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