Calculation of the Ldn (day, night) and the Lden (day, evening, night) based on 1-hour Leq measurements.
The Ldn is the average equivalent sound level over a 24 hour period, with a penalty added for noise during the nighttime hours of 22:00 to 07:00. During the nighttime period 10 dB is added to reflect the impact of the noise.
Ldn measurements are useful for assessing the impact that road, rail, air and general industry has on the local population.
The NoiseMeters Ldn calculator accepts hourly Leq measurements and calculates the Ldn accordingly.
The Lden (Day Evening Night Sound Level) or CNEL (Community Noise Equivalent Level) is the average sound level over a 24 hour period, with a penalty of 5 dB added for the evening hours or 19:00 to 22:00, and a penalty of 10 dB added for the nighttime hours of 22:00 to 07:00.
It is very similar in nature (and in results) to the Ldn, but with the added penalty for the evening period.
Our Lden or CNEL calculator takes the hourly Leq measurements and calculates the Lden (which is the same as the CNEL).