Acoustic pressure – this term refers to the variable deviation of static pressure in a medium during the propagation of acoustic waves. The deviation occurs over time and is measured from the average value of static pressure. The unit of measurement for acoustic pressure in the SI coordinate system is the pascal (Pa).
The reference pressure is the smallest acoustic pressure that causes any auditory sensation in humans. It is exactly 2·10−5 Pa. The level of acoustic pressure is nothing more than the logarithm of the measured pressure to the reference pressure.
Several factors influence the level of acoustic pressure, including:
– the position of the sound source, such as instruments;
– the size and shape of the room;
– the temperature and humidity of the air;
– the distance of the measurement point from the source of acoustic waves.
Acoustic pressure is inversely proportional to the distance of the meter from the sound source. Unfortunately, this proportionality changes in rooms where acoustic waves are additionally reflected from obstacles and walls.
