Reference

SoundsdB SPL
Rocket Launching180
Jet Engine140
Thunderclap, Air Raid Siren 1 Meter130
Jet takeoff (200 ft)120
Rock Concert, Discotheque110
Firecrackers, Subway Train100
Heavy Truck (15 Meter), City Traffic90
Alarm Clock (1 Meter), Hair Dryer80
Noisy Restaurant, Business Office70
Air Conditioning Unit, Conversational Speech60
Light Traffic (50 Meter), Average Home50
Living Room, Quiet Office40
Library, Soft Whisper (5 Meter)30
Broadcasting Studio, Rustling Leaves20
Hearing Threshold

Frank the Crank! about Decibels: dB Sound Level Meter, v1.0