The decibel is a logarithmic ratio between two values, not an absolute amount — which is why it always needs a reference to mean anything. In digital audio the reference is full scale, giving dBFS; for true peak it is dBTP; for acoustic level in air it is dB SPL. The log scale matches hearing: a +10 dB change sounds roughly twice as loud, +6 dB doubles amplitude, and +3 dB doubles power. Working in decibels lets engineers add gains instead of multiplying them and compresses the enormous range between a whisper and a jet into manageable numbers. Misreading which reference is in play is a common, costly mistake.
The book · Volume 4 of 7
Audio for Video: A Complete Guide to Sound in Video Products: From PCM and Codecs to Loudness, Accessibility, and Real-Time Voice Processing
The decibel is a ratio, so every number needs its reference, dBFS, dBTP or LUFS, and mixing them up leads to wrong loudness decisions. Volume 4 covers the decibel in detail: digital level, peak, RMS and LUFS, bit depth and dynamic range, and loudness targets for streaming and broadcast. Written by Nikolay Sapunov, CEO at Fora Soft.
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