Calculate the combined noise level when two sound sources are present simultaneously.
Decibels are logarithmic. Two 80 dB sources don't make 160 dB — they make 83 dB. This is because sound energy (in watts) adds linearly, but our perception and the dB scale are logarithmic. Doubling sound energy adds 3 dB.
Whisper: 30 dB. Normal conversation: 60 dB. Vacuum cleaner: 70 dB. City traffic: 80 dB. Rock concert: 110 dB. Jet engine at 30m: 140 dB. Hearing damage starts around 85 dB with prolonged exposure.