What is the reference pressure level for 0 dB SPL?

The reference pressure level for 0 dB SPL (Sound Pressure Level) is established at 20 micro Pascals (20 μPa). This measurement is significant because it represents the threshold of hearing for a young, healthy human ear. The decibel scale is logarithmic; therefore, 0 dB SPL does not imply a lack of sound but rather indicates the reference point at which the sound pressure is perceptible in an ideal listening environment.

This reference is crucial in audiology and sound measurement, as it provides a standard against which various sound pressures can be compared. Understanding that 20 μPa is the accepted standard allows professionals in the field to communicate about sound levels consistently and accurately.