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Room Decay and Sabine Estimate

Compare a Sabine room estimate with a supplied decay fit at an explicit frequency band, keeping small-room and measurement assumptions visible.

Use this result well

Inputs that matter
Room volume (m³), Equivalent absorption area (metric sabins), Frequency band center (Hz), Fitted decay interval, and 1 more
Output to expect
Estimated 60 dB decay time, Extrapolated 60 dB decay
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Sabine reverberation estimate

T ≈ 0.161 × room volume (m³) / equivalent absorption area (m²); equivalent area = Σ(surface area × absorption coefficient) A diffuse-field room approximation. The coefficient assumes metric units and typical room-air conditions; air attenuation is not separately included. Small booths, room modes, uneven absorption and non-diffuse fields can make this estimate unreliable. T20 and T30 are extrapolated 60 dB decay estimates from fitted portions of a measured decay; T30 is not half of RT60.

60 dB extrapolation from a fitted decay slope

T60 = −60 / fitted slope (dB per second) Slope conversion, not a decay-curve fit. EDT, T20 and T30 use different fitted ranges but all extrapolate to a 60 dB decrease. The tool cannot inspect fit linearity, noise-floor truncation or the suitability of the room sound field. A room with a changing decay slope can produce different estimates for these intervals.

Updated: September 2026

Example Scenarios

Use room volume and equivalent absorption area for one frequency band in the Sabine diffuse-field approximation.

Convert a fitted negative decay slope to a 60 dB decay time. Record which measurement interval was fitted.

Common Mistakes to Avoid

Applying sabine reverberation estimate outside its stated assumptions

The coefficient assumes metric units and typical room-air conditions; air attenuation is not separately included. Small booths, room modes, uneven absorption and non-diffuse fields can make this estimate unreliable. T20 and T30 are extrapolated 60 dB decay estimates from fitted portions of a measured decay; T30 is not half of RT60.

Applying 60 db extrapolation from a fitted decay slope outside its stated assumptions

EDT, T20 and T30 use different fitted ranges but all extrapolate to a 60 dB decrease. The tool cannot inspect fit linearity, noise-floor truncation or the suitability of the room sound field. A room with a changing decay slope can produce different estimates for these intervals.

FAQ

No. It estimates a band-specific decay from supplied absorption data.

No. Evaluate frequency-dependent decay, background noise and actual recordings.

Use the fitted slope in dB/s. A simple endpoint interval does not reproduce a regression fit.

No. Review the measured curve and actual recording quality.

About Room Decay and Sabine Estimate

Compare a Sabine room estimate with a supplied decay fit at an explicit frequency band, keeping small-room and measurement assumptions visible. Choose the mode that matches your measurements or study design, enter the stated units and keep the method and limits with the result.