Noise in open offices: what sound-masking research says

In an open office, the sound that is hardest to ignore is speech you can follow, not a loud hum. Sound masking adds a steady sound so that nearby talk is harder to make out. In a lab memory task, masking one voice with several other voices brought performance back to the level of silence. In an 18-week field study, swapping one masking sound for four water-based ones gave no gain on any subjective measure. This page covers what the studies measured and what they left open. It sits in our focus topic, so it reports what published sources found and promises no result.

Why is speech the problem in an open office?

Speech disrupts some kinds of work more than others. A study by Jahncke tested four task types: searching for information, remembering material, counting and generating words. Tasks built on short-term memory and rehearsal of the presented material were more sensitive to irrelevant speech than tasks that needed no rehearsal or relied on long-term memory. The author concluded that tasks such as information search and remembering material are a poor fit for places where irrelevant speech is common.

Workers say the same thing when asked. A survey of 1,078 people in Italy rated irrelevant speech as more annoying in open-plan offices (mean 3.07 on a 1 to 5 scale) than in shared offices of 2 to 5 people (mean 2.54). Open-plan respondents also reported more interruptions and lower performance. Those are self-reports, the design cannot show cause and effect, and the response rate was 17%, so people who were more annoyed may have been more likely to answer.

When asked how they cope, 32% of open-plan workers named technology such as headphones with music as their main strategy, against 22% in shared offices.

What did the studies look at?

Two studies tested masking itself.

The first, by Keus van de Poll and colleagues (2015), ran lab experiments. It starts from the point that broadband noise is the usual masking choice in open offices, yet office workers generally dislike it. So the team compared alternatives. In the first experiment, people did a serial short-term memory task under silence, a single voice, multiple voices, broadband noise and water waves. In the second, they wrote in a word processor with one, three, five or seven voices in the background. The abstract does not give participant numbers.

The second, by Hongisto and colleagues (2017), was a field experiment in one open-plan office. Staff had been used to a pseudo-random masking sound that the authors compare to a table fan. Over 18 weeks, in 3-week blocks, the office heard that sound, then four water-based sounds (a waterfall, a river, a babbling river and a river with occasional weak bird sounds), then the original again. Levels stayed between 43.0 and 44.6 dB LAeq. Of the 77 people invited, 28 to 47 answered each questionnaire, and the main analysis used the 18 who answered every time.

What did they find?

In the field study, acoustic satisfaction was lower with the water-based sounds than with the original, and the original scored the same before and after. Disturbance by noise was higher with the babbling river and the river with birds. Colleagues' speech also disturbed people more during the water-based blocks. The authors still caution that these results do not rule out water-based sounds as adequate masking.

What did they not find?

None of these studies shows that a masking sound makes people more productive at their own desk. The lab tasks were short and specific, a memory test and a writing task. The field study had no control group, a fixed order of conditions, no condition with masking switched off, and one workplace. Staff already knew the original sound. That may have coloured their ratings. One author works for a headset maker that co-funded the research.

The studies also tested room-level systems and lab playback. They did not test a personal sound on a phone, so they cannot say whether it would match either result. For a related look at one popular colour, see what studies found on brown noise for focus.

How can you try it yourself?

If you want to hear what a steady background does to nearby voices, start low. Pick a sound that sits just under the level of the talk around you, then listen for whether words stay easy to catch. Pink noise is a common starting point, and pink noise vs white noise explains how the two differ. Hush Machine is coming to iPhone. It makes its noise live on the phone, with one dial from white to deep brown, a timer and a fade, and nothing repeats. We make no promise about your focus. It is a sound to try, and the studies above are a good reason to keep expectations modest.

Bottom line

Speech is the office noise that research flags most often, and masking aims at it. The lab results are encouraging for tasks like memory and writing, while the one field study found no gain from changing the masking sound. The evidence is small and mixed, so any sound is something to test for yourself.