Table 1 A-weighted energy-average sound pressure level of bandlimited urban transport noise recordings before and active control with windows fully opened, and without active control with windows fully closed. Values inside the parentheses indicate the attenuation level.

From: Active control of broadband sound through the open aperture of a full-sized domestic window

Noise Type (Bandwidth, Hz)Duration, sEnergy-average SPL, dBAPlanar-average SPL, dBA
Before controlAfter control (Attenuation)Passive (Attenuation)Before controlAfter control (Attenuation)Passive (Attenuation)
Gaussian white noise (100 to 1000)1074.6065.80 (8.80)61.80 (12.8)79.9070.30 (9.60)65.21 (14.69)
Highway noise (100 to 1000)6.6472.9364.26 (8.67)60.02 (12.91)78.2068.95 (9.25)63.62 (14.58)
MRT noise (100 to 1000)12.6477.4767.33 (10.14)65.11 (12.36)82.5971.15 (11.44)68.17 (14.42)
Aircraft fly-by noise (100 to 1000)19.1170.6963.18 (7.51)56.79 (13.9)75.8867.18 (8.7)59.65 (16.23)