Acoustical Engineering - Architectural Acoustics

Architectural Acoustics

Architectural acoustics refers to the control of sound and vibrations within buildings. Although architectural acoustics was first applied to opera houses and concert halls, this branch of acoustical engineering applies to any enclosed area, whether concert halls, office spaces, or ventilation ducts.

The acoustics of rooms are often considered to ensure speech intelligibility and privacy. One thing that can affect speech intelligibility is standing waves. A standing wave results from a sound wave reflected 180 degrees out of phase with its incident wave, which often occurs for at least one specific frequency when two walls are placed parallel to each other. To avoid this, many rooms are designed with angled walls. A second potential cause of poor speech intelligibility is reverberation. This effect can be reduced through porous absorbing materials. Examples of these include glass or mineral fibers, textiles, and polyurethane cell foams. Since the absorption of each material is different for different frequencies of sound, the materials used often vary based on the intended purpose of the room, though compound partitions, or layered combinations of different materials, make more effective absorbers. A third common technique for room acoustics is the use of masking. Masking is the canceling or drowning out of other sounds. Although this raises the overall sound pressure, masking can make irritating noises less distracting and add speech privacy. As these examples highlight, room acoustics are a regular part of architectural design.

Reducing ventilation noise serves as another example of applied architectural acoustics. Many heating, ventilation, and air conditioning systems have silencers. Silencers can actively cancel noise by electronic feed forward and feedback techniques, or muffle the sound by either having sudden changes in cross section or walls with absorbent linings. Architectural acoustics involves the control of sound for ventilation, rooms, and anything else indoors.