Sound Pressure Meter (SPL) is meant for noise measurement. It calculates in Decibel or dB. It collects the noise from environment. Levels of Noise In decibels (dB) according to American Academy of Audiology (www. Audiology. Org): 140 dB - Gun shots, fireworks. 130 dB - Jackhammers, Ambulance. 120 dB - Jet planes taking off. 110 dB - Concerts, Car horns. 100 dB - Snowmobiles.