Loudness Frequency Analyzer
See the level of each octave band from your microphone under A-, C- or Z-weighting — revealing which frequencies your ear actually hears as loudest, not just where the raw energy is.
ℹ Relative dBFS, not calibrated. The weightings are the standard frequency curves (A ≈ how the ear judges loudness at moderate levels; C ≈ near-flat for loud sounds; Z = flat/unweighted). Readings come from an uncalibrated mic and include your room, so compare bands against each other — the numbers aren’t absolute SPL. Nothing is recorded.
Weighting & Perceived Loudness
Human hearing isn’t equally sensitive at every frequency — we hear the midrange (around 1–4 kHz) most easily, and need much more energy in the deep bass or extreme treble for it to sound equally loud. That sensitivity is captured by equal-loudness contours (the Fletcher–Munson curves and their modern ISO 226 successors). The standard weighting filters approximate this: A-weighting rolls off lows and very highs to match how we judge loudness at moderate levels; C-weighting is much flatter, suited to loud sounds and peaks; Z-weighting is flat (no weighting).
This analyzer applies the chosen weighting to each octave band, so the bars show roughly how loud each band sounds rather than its raw energy. Switching to Z reveals the unweighted spectrum; switching to A shows why a bass-heavy signal can measure high yet not sound that loud. Because it’s a relative, uncalibrated mic reading, treat the shape — which bands dominate — as the takeaway, not the absolute dB.