# Sound Pressure Level

## Description

Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average, or equilibrium) atmospheric pressure, caused by a sound wave.

Sound pressure level or sound level is a logarithmic measure of the rms sound pressure of a sound relative to a reference value.

When referring to measurements of power or intensity, a ratio can be expressed in decibels by evaluating ten times the base-10 logarithm of the ratio of the measured quantity to the reference level.
Here we can calculate Sound Pressure Level, Sound and Reference Pressure.

Thus, the ratio of a power value P to another power value P0 is represented by LdB, that ratio expressed in decibels.

## Variables

SPL | Sound Pressure Level (in dB) (dimensionless) |

P_{RMS} | The root mean square Sound Pressure (Pa) |

P0 | Reference Pressure (Pa) |