The DecibelThe NeperConcepts Underlying the Decibel and Its Use in Sound SystemsMeasuring Electrical PowerLevels in dBThe Decibel in Acoustics—LP, LW, and LIAcoustic Intensity Level (LI), Acoustic Power Level (LW), and Acoustic Pressure Level (LP)Inverse Square LawDirectivity FactorOhm’s LawA Decibel Is a Decibel Is a DecibelThe Equivalent Level (LEQ) in Noise MeasurementsCombining DecibelsCombining VoltageUsing the Log ChartsFinding the Logarithm of a Number to Any BaseSemitone IntervalsSystem Gain ChangesThe VU and the VI InstrumentCalculating the Number of Decades in a Frequency SpanDeflection of the Eardrum at Various Sound LevelsThe PhonThe Tempered ScaleMeasuring DistortionThe Acoustical Meaning of Harmonic DistortionPlayback Systems in StudiosDecibels and PercentagesSummary