What units are sound pressure level measured in?

What units are sound pressure level measured in?

• A. Newtons per square meter (N/m^2)
• B. Decibels (dB)
• C. Pascals (Pa)
• D. Watts per square meter (W/m^2)

Answer: (B)

Sound pressure level is expressed in decibels because human hearing responds logarithmically to pressure changes, so we compare the actual sound pressure to a fixed reference and express that ratio on a log scale. In air, the standard reference pressure is 20 microPascals (20 μPa). The SPL is calculated as 20 log10(p_rms / p0), giving the result in decibels (dB). While the physical pressure itself is measured in Pascals (N/m^2), the level used for hearing, loudness, and comparison is the logarithmic dB scale. Other measures like W/m^2 describe radiant energy flux, not sound pressure level.

Sound pressure level is expressed in decibels because human hearing responds logarithmically to pressure changes, so we compare the actual sound pressure to a fixed reference and express that ratio on a log scale. In air, the standard reference pressure is 20 microPascals (20 μPa). The SPL is calculated as 20 log10(p_rms / p0), giving the result in decibels (dB). While the physical pressure itself is measured in Pascals (N/m^2), the level used for hearing, loudness, and comparison is the logarithmic dB scale. Other measures like W/m^2 describe radiant energy flux, not sound pressure level.