Glossary

The long-term energy equivalent sound level (in short: LpAeq) is a measure for the average noise exposure over a certain period in which frequency, duration and level of the individual sound events are taken into account. The LpAeq is the basis for the determination of noise protection zones pursuant to the aviation noise act – separated according to day (6 a.m. – 10 p.m.) and night (10 p.m. – 6 a.m.). The LpAeq is stated in dB.

The loudness is more a matter of perception. Two tones with the same sound level but different frequency are often perceived as being differently loud. The measurement unit of loudness is the “phon” and the definition of phon is based on the subjective comparison of two sound events.