Day-Evening-Night Level
Calculate Lden from 12-hour day, 4-hour evening, and 8-hour night Leq values with 5 dB and 10 dB penalties.
Description
Day-evening-night level (Lden) combines duration-weighted sound energy with evening and night penalties.
Day-evening-night level (Lden) combines duration-weighted sound energy with evening and night penalties. Averaging the decibel numbers directly gives a different quantity.1
The returned values include Lden. The How section below explains the calculation, input rules and interpretation.
When to use Day-Evening-Night Level
Use Day-Evening-Night Level when you need to evaluate the supplied records under the calculation and evidence rules below. No alternate time periods, measured integration or local assessment rule is selected.
Choose the measured quantities, units, weighting and measurement basis before entering values. For a reference, select the exact topic. For a catalog lookup, prepare complete source-backed records; for a screen, select an applicable caller limit.
How to use Day-Evening-Night Level and understand its results
- Choose the measured quantities, units, weighting and measurement basis before entering values. For a reference, select the exact topic. For a catalog lookup, prepare complete source-backed records; for a screen, select an applicable caller limit.
- Enter dayLevelDecibels, eveningLevelDecibels, nightLevelDecibels using the field table and calculation rules, then run the tool.
- Read ldenDecibels. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| dayLevelDecibels | Day Leq (dB) | number | Required |
| eveningLevelDecibels | Evening Leq (dB) | number | Required |
| nightLevelDecibels | Night Leq (dB) | number | Required |
Enter three finite segment levels in decibels. Apply fixed periods of 12, 4 and 8 hours and penalties of 0, 5 and 10 dB. Calculate the energetic mean; use shifted logarithmic arithmetic if the direct powers overflow or underflow. Return a finite Lden.
Lden=10log10((12×10^(day/10)+4×10^((evening+5)/10)+8×10^((night+10)/10))/24) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| ldenDecibels | Lden (dB) | number |
{
"input": {
"dayLevelDecibels": 60,
"eveningLevelDecibels": 55,
"nightLevelDecibels": 50
},
"output": {
"ldenDecibels": 60
}
}Limitations and assumptions
No alternate time periods, measured integration or local assessment rule is selected.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing fields without a declared default, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use DNL Segment Level Solver: Day-night average sound level (DNL) energetically combines 15 day hours and 9 night hours with a 10 dB night penalty. One segment can be solved when the other and total are known. For a complementary task, use Festival Noise Limit Screen: An event noise screen can conservatively add an explicit uncertainty allowance to a measured level before comparison. All values need the same weighting and assessment interval.
References
-
Day-Evening-Night Level — tool.io
Similar or alternative tools
- DNL Segment Level Solver
Day-night average sound level (DNL) energetically combines 15 day hours and 9 night hours with a 10 dB night penalty. One segment can be solved when the other and total are known.
- Festival Noise Limit Screen
An event noise screen can conservatively add an explicit uncertainty allowance to a measured level before comparison. All values need the same weighting and assessment interval.