Sound pressure level

Definition

Sound pressure level (SPL) is a measure of the pressure of a sound relative to a reference value, typically measured in decibels (dB). It quantifies the amplitude of sound waves and is crucial in understanding sound intensity.

5 Must Know Facts For Your Next Test

1. SPL is commonly measured in decibels (dB), using a logarithmic scale.
2. The reference point for SPL in air is typically set at 20 micropascals, which is considered the threshold of human hearing.
3. An increase of 10 dB represents a tenfold increase in sound intensity.
4. SPL can be calculated using the formula $L_p = 20 \\log_{10}(p/p_0)$, where $p$ is the root mean square sound pressure and $p_0$ is the reference sound pressure (20 µPa).
5. SPL measurements are critical for various applications including audio engineering, environmental noise assessment, and hearing protection.

Review Questions

• What unit is used to measure Sound Pressure Level?
• How does an increase of 10 dB affect sound intensity?
• What is the reference pressure value used for SPL measurements in air?

Related terms

Decibel (dB): A logarithmic unit used to express the ratio of two values, commonly used to measure sound intensity.

Sound Intensity:

The power carried by sound waves per unit area, usually measured in watts per square meter (W/m²).

Threshold of Hearing:

The minimum sound pressure level that can be heard by the average human ear, typically defined as 0 dB SPL or 20 micropascals.