Science

It's not just volume — types of office sounds and where they're coming from influence how distracting you find them

The hum of air conditioning. Music coming from the kitchen. The drone of traffic outside. Your colleagues sharing weekend plans.

Soundscapes in open-plan offices can make it extremely difficult to concentrate and get your work done.

While wearing headphones is one commonly offered solution, researchers are looking at how we perceive sound to help improve workplace design.

Some of what they have found might help you get a handle on your noisy office.

Not all noises are bad

Some noises can be quite useful, said Densil Cabrera, who works in architectural acoustics at the University of Sydney.

"Sometimes noise that people don't notice helps mask sound from other people, for example," Dr Cabrera said.

So thank your trusty air-conditioner for not only keeping you cool, but also ensuring you don't have to hear all the intricate details of your colleague's kid's costume for the school concert.

Some types of sound are more distracting

"Different types of noise will attract different amounts of attention," Dr Cabrera said.

"Sound that is tonal — in other words, that you can literally sing if you wanted to — is very hard to ignore. And sound that fluctuates at a certain rate is also very hard to ignore."

Which explains why it's almost impossible to ignore the wail of an ambulance siren, which was designed on both these principles, making it an extremely attention-grabbing sound (although generally not the type of sound people want to listen to at work).

We're also well attuned to listening to the humans around us.

"People are tuned into speech because people are people," Dr Cabrera said.

"One-sided conversations where someone's on a phone can be particularly hard to ignore, because you're second-guessing what the other person may have been saying."

Dr Cabrera and his colleague Manuj Yadav conducted some experiments on how much speaking causes issues in a simulated open-plan office environment.

They found it actually didn't really matter how loud the speech was, but that more people talking created more distraction.

The flipside of these sounds are certain types of machinery noise, which are really innocuous, steady-state sounds.

Without tonal components, these noises are much less attention-grabbing than speech or music, Dr Cabrera said.

How important is where the sound is coming from?

The direction the sound is coming from could also have an impact, according to preliminary research being presented at the 178th Meeting of the Acoustical Society of America this week.

In a trial study, environmental psychologist Takeshi Akita and colleagues from Tokyo Denki University played three different types of sound — speech, music and an alert sound similar to an alarm — to 20 individual study subjects.

The subjects were played the sounds at both 50 and 60dBA (A-weighted decibels, which measures the relative loudness of sounds as perceived by the human ear) from a speaker in front of them, from a speaker behind them and also from speakers to their left and right, while they were working on another task in an experimental room.

They were then asked to evaluate the sounds, including questions about whether the sounds bothered them.

Results from the study showed people found quieter sounds less distracting, but the alert sound was bothersome at both volumes.

50dBA of speech or music played from behind the subjects didn't appear to worry them much, but louder music presented from their left or right was as distracting as the quieter alert tone.

"[We] suppose that sound from behind is not so obstructive when the attention of subjects is [what's in front of them], because the direction of the sound and attention is clearly separated," Professor Akita said.

Dr Cabrera is also researching how the design of workplaces can provide better acoustic support to people.

"People tend to lower their voices when they can hear their voice better," he said.

"So far we haven't managed to do a large demo of this concept, so I can't really say we've got a solid finding from that yet."

So what does this mean today, for making your office more bearable?

"At the present stage, I can only say that perception of sound may be affected by the attention to the sound and direction," Professor Akita said.

"It may be useful to consider the relation between the source of sound and … which direction [office workers] sit and do their tasks."

Or in other words, until your cone of silence gets installed, make sure your most annoying colleagues are behind you.