dB vs dBA: Weighting Explained
dB is the unit; the trailing letter says which frequency weighting was applied.
Last materially reviewed: 2026-09-16
- dBZ (Z-weighted). Flat: all frequencies count equally. Best for comparing spectra and for calibration math.
- dBA. A-weighting roughly follows human hearing at moderate levels — quiet low frequencies count less. Default on this meter for everyday environments and decibel chart comparisons.
- dBC. Flatter than A; closer to how loud peaks feel. Useful near loud machinery or music.
Which weighting should I pick?
Everyday room and street checks: A. Loud bass-heavy events: compare A and C. Technical comparison between two recordings: Z, with identical response. Whichever you pick, calibrate with the same weighting you measure with.
Fast vs Slow
Fast (125 ms) follows peaks; Slow (1 s) smooths them. Neither changes the underlying estimate — only how quickly the display follows it. Leq (energy average) accumulates independently of the display smoothing.