Decibel
A decibel (symbol dB) was a measurement of the volume of sound.

In 2267, the  was bombarded by sonic vibrations from Eminiar VII equal to 1812 decibels. ()

The acceptable level of noise on Deep Space 9 was 70 decibels; anyone who was louder than that could be charged with disturbing the peace. ()

According to Quark, the usual ambient noise level at Quark's was sixty-five decibels, and with Klingons present up to 85 decibels. When the soldiers of a Klingon task force visited Quark's in 2372, the unusual quietness of less than 30 decibels worried Quark. Later, when the Klingons had left, the noise level was back up to 72 decibels again, which greatly pleased Quark. () 

In order to get two meters of electro-plasma conduit from the  in 2373, Nog listened to Worf's Klingon operas at 82 decibels to filter out sub-harmonic distortions. ()

External link 
 

de:Dezibel
Measurements