Washington, May 20 (IANS): Playing natural sounds such as flowing water in offices could lift workers' moods and enhance productivity, a new study says.

An increasing number of modern open-plan offices employ sound masking systems that raise the background sound of a room so that speech is rendered unintelligible beyond a certain distance and distractions are less annoying.

"If you are close to someone, you can understand them. But once you move farther away, their speech is obscured by the masking signal," explained Jonas Braasch, acoustician and musicologist at the Rensselaer Polytechnic Institute in New York.

The sound masking system also improves cognitive abilities in addition to providing speech privacy.

The natural sound used in the experiment was designed to mimic the sound of flowing water in a mountain stream.

"The mountain stream sound possessed enough randomness that it did not become a distraction. This is a key attribute of a successful masking signal," added co-author Alana DeLoach.

Sound masking systems are custom designed for each office space by consultants and are typically installed as speaker arrays discretely tucked away in the ceiling.

For the past 40 years, the standard masking signal employed is random, steady-state electronic noise -- also known as "white noise".

Using natural sounds as a masking signal could have benefits beyond the office environment.

The workers, who are listening to natural sounds are more productive and overall in better moods than the workers exposed to traditional masking signals.

"You could also use it to improve the moods of hospital patients, who are stuck in their rooms for days or weeks on end," Braasch noted.

The authors were scheduled to present their findings at the 169th meeting of the Acoustical Society of America in Pittsburgh.