Minimizing Noise, Maximizing Sound
A look at how important sound absorption is in determining a room’s acoustics.
A new wing in the hospital features large windows that allow more light in the facility, helping promote a healing environment. At the same time, these windows also let in noise from the outside that can potentially disrupt patients and their visitors. The issue of greater noise is compounded by hard floors, which are necessary to accommodate furniture and devices with wheels but can also amplify sound.
In many areas of the hospital, even a penny dropping seems loud. Drop the same penny in the newer wing, however, and most people wouldn’t even hear it.
The Difference Is In The Ceilings
Sound absorption is seen by many experts as the single most important factor in determining a room’s acoustics. Adequate sound absorption occurs through a combination of the room’s floor, walls and ceiling, with ceilings often serving as the most effective way to minimize noise and help the acoustics. That’s because sound reflects upward. With the wrong type of ceiling, that sound will bounce back into the room, making it too loud and difficult to communicate. With the right type of ceiling, ambient noise will be minimized.
This is especially important in classrooms as many teachers spend less time standing in front of traditional rows of desks, opting instead for flexible environments that foster discussions and support interactive learning. That makes it essential for students on one side of the room to hear classmates on the other. Many schools are also located in older buildings, where background noises can make it difficult for students to hear each word their teachers say or to participate in conversations.
In the Netherlands, for instance, architects have taken a former tax authority building with classic architecture and transformed it for the University of Amsterdam. A similar effort to use the building as a high school failed in the 1990s but the college has succeeded—partly because of new solutions for the ceilings. Consider one corridor that’s between a courtyard and a place where students gather and eat. Noise is constant in the two-floor area, according to this article, but with effective sound absorption, it’s still easy to hold conversations. In another portion of the school, where performances are common, Rockfon installed a monolithic acoustic ceiling. The result: significantly improved acoustics.
Other Facilities Where Sound Absorption Is Crucial
Offices—more offices have adopted open-space plans, and that can make it more difficult to have private conversations and more essential to minimize excessive noise so that people can concentrate.
Gymnasiums and aquatic centers—these buildings have hard surfaces that reflect noise. In addition, sound can be amplified over water.
Areas with limited headroom—sound is more likely to reflect in these spaces that often feature hard flooring, such as stairwells, corridors and basements.
There are a number of ways a ceiling can absorb sound, including the materials used in ceiling composition. The non-directional fiber orientation of stone wool, for instance, reduces the intensity of noise and how much it spreads throughout a room. If the sound gets absorbed, it will not be reflected into the room, avoiding echoes or the “cocktail party” effect.
A key yardstick for measuring the acoustical properties of ceilings is the noise reduction coefficient. This is measured in multiples of 0.05, and it ranges from a score of 0.00 to a score of 1.0, which means that all sound is absorbed. A higher NRC will do a better job of lowering sound pressure in both the room where the sound originates and the nearby rooms where it could be overheard.