Office speech levels are influenced by environment, design and meeting type, Concordia study shows

Most offices have that one worker who has problems controlling their indoor voice. Either too loud or too soft, it can be distracting to colleagues — especially as workplaces become increasingly open concept, with fewer closed offices to ensure privacy and quiet.

A new study by Concordia researchers published in Science and Technology for the Built Environment reveals the volume of office speech is often shaped by more than personal habits. The speech level of workers is the most important, but a workspace’s physical design and communication type matters as well.

Rather than try to simulate an office environment in a lab, the researchers chose to examine real-world speech levels in two active offices, one in Montreal and the other in Quebec City, with more than 70 employees speaking in either English or French.

Using high precision sound meters to capture the differences in sound levels, the researchers recorded the workers across a variety of office environments, workstations and activities. Measurements were taken during conversations and short readings in open-plan offices with and without partitions, in private offices, and in small and large meeting rooms. Interactions ranged from casual chats to online meetings with and without headsets.

The study, conducted in collaboration with Montreal-based acoustics firm Soft dB, also accounted for background noise and room acoustics.

Desk partitions may not be as effective as thought

“We found that people speak significantly louder if they are in an open-plan office with partitions separating the work stations,” says Joonhee Lee, an associate professor in the Department of Building, Civil and Environmental Engineering and the study’s corresponding author.

“When the participants sat at a desk with partitions, they naturally increased their speech level. While the partitions are effective at attenuating speech, their full benefit may not be realized, as the workers may feel they are able to talk louder than they otherwise would without the partitions.”

Meeting rooms, by contrast, showed consistent speech sound levels regardless of their size, while teleconferences led to slightly higher speaking volumes compared to face-to-face discussions. Language did not have significant effect on speech levels.

One of the most striking findings was that real-world speech levels were lower overall than those used in industry standards. These standards are often based on laboratory tests in anechoic chambers, where there is no reflective feedback that naturally helps a talker gauge their speech strength. This suggests that existing standards for speech privacy and noise control in office design may not accurately reflect how loudly people actually speak to one another in office environments.

Lee notes that optimal office environments include at least some background noise — and that a completely noise-free environment could be almost as distracting as an overly noisy one.

“A decrease in background noise only amplifies the perception of other kinds of noise,” he says. “Some degree of background noise actually helps people perform better.”

PhD candidate Rewan Toubar and Roderick Mackenzie, deputy director of acoustical consulting at Soft dB, co-authored the paper.

Funding was provided by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

Read the cited article: “Speech level variation by office environment and communication type”