The sound level is defined as the change in pressure caused by the vibrating air molecules. The sound pressure range that our ears can pick up is between 0,00002 pascal and 20 pascal (at 1000 Hz). That corresponds to a factor of 1 in 1 million. The same range is also found in amplifiers.
In order to be able to mathematically grasp such a large area more easily, the logarithmic ratio was used decibels (dB) introduced. In the case of sound pressure, the sound level is therefore denoted by dB.
A sound pressure of 0,00002 pascal corresponds to a sound level of 0dB, a sound pressure of 20 pascal to a sound level of 120 dB. A normal conversation generates a sound level of around 1 dB at a distance of 60 m. A rock concert often reaches the pain threshold. A difference in SPL of 10 dB is perceived as double the volume. Differences of 3 dB are clearly audible, smaller sound pressure differences are usually only noticeable in a direct comparison.
sound power:
The sound power of various natural musical instruments:
Trumpet approx. 0,3W
piano approx. 0,5 W
Timpani approx. 12 w
Symphony Orchestra approx. 70W
About the Pascal unit: 1 Pascal = 1 Pa = 1 Newton / square meter = 1N/m²