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🔊 Reverberation Time Explorer
A room, four surfaces, two competing formulas. Change the finishes (how absorptive floor, ceiling, walls, and windows are) and watch RT60 respond live — by both Sabine (1898) and Eyring (1930). The two agree at low absorption and deliberately disagree at high absorption, which is the point: Sabine's formula has a known blind spot there.
Room
Surfaces (area m² / absorption α)
SurfaceAreaα (0–1)
Floor
Ceiling
Walls
Windows
Typical α: painted plaster/gypsum ≈0.05–0.1, acoustic ceiling tile ≈0.5–0.8, heavy carpet ≈0.3–0.5, glass ≈0.03–0.18, thick curtains ≈0.5–0.7.
Live Result
Total surface area S—
Total absorption A—
Average absorption ᾱ = A/S—
Sabine RT60—
Eyring RT60—
Powered by the exact Sabine and Eyring equations
(engine/acoustics.js) — independently re-verified against a Python
cross-check before publishing (worked classroom example matched to 3 decimal
places; the 0.161 constant matched its 55.3/c derivation; Eyring→Sabine
convergence at low ᾱ and Eyring→0 / Sabine-stays-nonzero at high ᾱ both
reproduced the documented behaviour of each formula).
Method
Sabine (1898)RT60 = 0.161·V/A [s] — the classical reverberation-time formula, diffuse-field assumption.
Eyring (1930)RT60 = 0.161·V/(−S·ln(1−A/S)) [s] — corrects Sabine's failure to reach 0 as absorption→100%.
Scope: broadband (frequency-independent) absorption coefficients only — no octave-band analysis, no air-absorption term (relevant mainly in large volumes at high frequency), no room-shape/diffusion effects. Both formulas assume a reasonably diffuse sound field.