What does SAC stand for in acoustics?

• A. Sound Absorption Coefficient
• B. Sound Absorption
• C. Sound Transmission Class
• D. Noise Reduction Coefficient

Answer: (A)

The main idea tested is how much sound energy a surface absorbs. SAC stands for Sound Absorption Coefficient, which is a value between 0 and 1 indicating the fraction of incident sound energy that is absorbed by the surface. For example, a SAC of 0.8 means 80% of the sound energy is absorbed and 20% is reflected. This absorption can vary with frequency, so you’ll often see SAC given as a curve or at specific frequencies.

This concept is different from Sound Transmission Class, which measures how well a barrier blocks sound from passing through, and from Noise Reduction Coefficient, which is an average of absorption over several frequencies. Among the options, the term that SAC represents is Sound Absorption Coefficient.