Equivalent Sound Level for Fixed Sources
Sound intensity level is the level of the intensity of a sound relative to a reference value.
Equivalent sound level is proportional to the logarithm of the ratio between the time the source is on and the total time added to the steady-sound level.
Formula
![Copy to Clipboard QuantityVariable[Subscript["L", Style["eq", Italic]], "LogarithmicSoundPressure"] == Log[QuantityVariable[Subscript["t", Style["on", Italic]], "Time"]/QuantityVariable["T", "Time"]]*Quantity[10/Log[10], IndependentUnit["decibels sound pressure level"]] + QuantityVariable[Subscript["L", "s"], "LogarithmicSoundPressure"]](https://www.wolframcloud.com/objects/resourcesystem/marketplacestorage/resources/e1f/e1fb0bfb-31ed-45c0-ab9a-c59caa35529a/Webpage/FormulaImage.png)
| symbol | description | physical quantity | 
|---|---|---|
| Leq | equivalent sound level | "LogarithmicSoundPressure" | 
| T | total time | "Time" | 
| ton | time source is on | "Time" | 
| Ls | steady-sound level | "LogarithmicSoundPressure" | 
Forms
Examples
Get the resource:
| In[1]:= | ![ResourceObject["Equivalent Sound Level for Fixed Sources"]](images/e1f/e1fb0bfb-31ed-45c0-ab9a-c59caa35529a-io-1-i.en.gif) | 
| Out[1]= |  | 
Get the formula:
| In[2]:= | ![FormulaData[
 ResourceObject["Equivalent Sound Level for Fixed Sources"]]](images/e1f/e1fb0bfb-31ed-45c0-ab9a-c59caa35529a-io-2-i.en.gif) | 
| Out[2]= |  | 
Use some values:
| In[3]:= | ![FormulaData[
 ResourceObject[
  "Equivalent Sound Level for Fixed Sources"], {QuantityVariable[
\!\(\*SubscriptBox[\("L"\), 
StyleBox["\<\"eq\"\>",
StripOnInput->False,
FontSlant->Italic]]\),"LogarithmicSoundPressure"] -> 
   Quantity[65, IndependentUnit["decibels sound pressure level"]]}]](images/e1f/e1fb0bfb-31ed-45c0-ab9a-c59caa35529a-io-3-i.en.gif) | 
| Out[3]= |  | 
 
                 
                