Part 2 of our series on user comfort in unexpected acoustic environments.
Sound masking is traditionally used in open plan offices, medical facilities and professional suites, where it reduces intrusive noise and improves speech privacy. It has also been installed successfully in less traditional settings, but these are much less researched.
A crowded field of standards
Measuring noise means choosing from a wide range of standards and guidelines. In Australia, AS/NZS 2107:2016 (Acoustics — Recommended design sound levels and reverberation times for building interiors) is typically used to measure sound masking within buildings. AS/NZS 2702:1984 (Acoustics – Methods for the measurements of road traffic noise) provides guidelines for road traffic noise. Outside Australia, much of the research uses other parameters. The widely used WHO guidelines, for example, rely on the European Union Directive.
The gap between numbers and experience
None of these standards fully captures how people actually experience noise, especially when guidelines assume an average of ambient sound that hides a wide variation. The Victorian EPA’s recent attempt to designate and zone urban noise shows how complex the task is. It’s understandable that standards sometimes fall short for residents.
For non-traditional settings, the recommended sound level can be non-existent, unclear or unsuitable for real user comfort. Balancing an objective standard with subjective experience is difficult. But slavish adherence to recommended levels and shapes can limit how effectively this technology is used. Some specifications may even exclude off-the-shelf sound masking products that would improve comfort. This matters most for low-frequency environmental noise, which has a significant impact on human health.
How we measured
For user comfort and onsite measurement, we used A-weighted decibels (dBA) and AS/NZS 2107:2016 as a comparison tool.
The next three posts look at three real-world case studies where sound masking wouldn’t normally be recommended.