Research shows that acoustics are an integral part of an effective workplace. Employees are more satisfied and organizations more profitable when their facility provides the requisite level of speech privacy and noise control.

However, noise control strategies are often pursued in the ‘Quest for Silence’ – the mistaken belief that good acoustics are achieved when the sound levels in a space are as low as possible. Just as with ergonomic factors such as light, temperature and humidity, there is a comfort zone for the volume of sound, but it is not zero.

The ‘noise floor’ is the level of continuous sound that characterizes a space at any given time. If this floor is too high, the environment is irritating and tiring. If it is too low, conversations and noises are easily overheard, reducing speech privacy and productivity. The noise floor in offices is often so low that voices carry intelligibly over a distance of 50 feet (15 meters) or more.

A sound masking system addresses these issues.This type of system consists of a series of loudspeakers installed in a grid-like pattern above the ceiling, and a method of controlling their output. The loudspeakers distribute a background sound throughout the facility, raising the noise floor to a comfortable 42 to 48 dBA, or higher where required.

Many people still refer to this technology as white noise; however, this is a misnomer. The term ‘white noise’ describes a specific type of sound used in masking systems developed in the 1970s. These products were largely unsuccessful due to their inflexibility and the hissing quality of the sound they produced, but the name became widely adopted. Newer masking systems do not use a white noise signal.

Sound masking increases speech privacy. It also reduces the amount of disruption caused by noises, either by covering them completely or by decreasing the magnitude of change between baseline and peak volumes. In addition, it minimizes the differences in the level and quality of sound across the space, making the facility ‘feel’ quieter and movements from one area to another less disruptive.

While every sound masking system fulfills the basic function of introducing a background sound into the space, the methods they use to create, distribute and adjust the masking sound differ.

The oldest type of system is known as a centralized system, which consists of a centralized rack of equipment, including a sound generator, amplifiers and an equalizer, connected to a grid of speakers installed in the ceiling.

In a decentralized system, all of these electronic components are built into ‘master’ speakers. These systems offer greater localized adjustment capabilities; however, you must enter the ceiling and manually make these adjustments at each ‘master’ speaker.

The newest type of system is the networked system, a category created with the launch of the LogiSon® Acoustic Network in 2003. This technology offers the highest number of localized masking, paging, timer and keypad adjustments and allows them to be made centrally from a control panel or software. Changes can be applied to one speaker, a group or the entire system within minutes.

Sound masking is easily installed in existing facilities, providing an effective way to treat acoustic problems at nominal cost. However, early inclusion can reduce project costs by eliminating the need for extra insulation or layers of drywall, plenum barriers, and high-spec or permanent walls around private offices. In this way, masking also helps to maintain the flexibility of the space. In open plan spaces, masking can also help to maintain a level of acoustical control as density increases and workstation partitions become lower.

If the sound masking is augmented by strategies such as including physical barriers and absorptive materials in the design, the result will be an even more comfortable acoustic environment.

This article was provided by Environmental Acoustics Inc., the leading provider of sound masking solutions in Ontario. Contact the company to discuss a project or to request a copy of their Understanding Sound Masking brochure, which responds to the questions most frequently asked about this technology: Tel: 905-238-1077, Email: info@enviraco.com.