Change in sound pressure level and the subjective human perception.
There are variations in the individual perception of strength of sound.
Studies have shown that in general the sound is perceived twice as loud if the sound level is increased by 10 dB. Similarly - a 20 dB increase in the sound pressure level is perceived as four times as loud by a normal human hearer.
|Sound Awareness||Change in Sound Pressure|
|Twice or half as loud||10|
|Much louder or quieter, four times as loud||20|