It is significant and prioritizes modifying the background sound (in contrast to background noise); however, there is substantial evidence produced and published by Banneker (BBN) and Kavanaugh (et al., 1962 Speech Privacy in Buildings) indicating that acoustical satisfaction within a space cannot be guaranteed without consideration of the three principal parameters of architectural acoustical design, formalized and established in the early 1900s by Sabine.
The masking sound spectrum (National Research Council of Canada's COPE curve) is generated to be comfortable and elevated in level to be conducive to acoustical privacy in the built and occupied environment and can be specified up to 48dBA.
It is an effective solution to promote compliance with regulations that require measures to be taken to prevent verbal communication from being overheard, such as HIPAA (US) and GLBA (US) in medicine and finance respectively.
Several cases exist where sound masking has been successfully installed for exterior applications, the most common target of concern being roadway noise.
In one example application, a large artificial waterfall was constructed as part of the garden exterior of an urban hotel in Santa Rosa, California.
The waterfall cascades down an extensive wall approximately four meters in height and functions both for sound masking and as a physical barrier to road noise.
Plenum-based speakers typically range 4–10 inches (10–25 cm) in diameter and generally face upwards, towards the upper deck.
Disregarding the importance of any of these stages in implementation will result in a sound masking system that does not perform according to the specifications of an acoustician.