Reverberation Time Calculator

Calculate RT60 reverberation time for room acoustics using Sabine's formula

Room Dimensions

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m
m

Doors

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m

Windows

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m
Absorption Coefficients (Advanced)

Typical: 0.05 (painted concrete)

Typical: 0.03 (plaster)

Typical: 0.02 (concrete)

Typical: 0.10 (wood door)

Typical: 0.25 (glass window)

Reverberation Time Results

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RT60 (seconds)
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Room Volume (m³)
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Absorbing Area (m²)

Formula used: RT60 = 0.163 × V / A (Sabine's formula)

Room assessment: Enter room dimensions

Enter room dimensions

Example Calculation

Lecture Hall Example

Room: 12m × 8m × 3m lecture hall

Volume: 288 m³

Doors: 2 doors (2m × 0.9m each)

Windows: 4 windows (1.5m × 1m each)

Calculation Steps

1. Calculate surface areas: Walls = 120 m², Ceiling = 96 m², Floor = 96 m²

2. Subtract openings: Effective wall area = 120 - 3.6 - 6 = 110.4 m²

3. Calculate absorbing area: A = Σ(α × S) = 7.33 m²

4. Apply Sabine's formula: RT60 = 0.163 × 288 / 7.33 = 6.40 seconds

This is too reverberant for speech - need acoustic treatment!

Common Absorption Coefficients

Concrete (painted)0.05
Carpet (thick)0.35
Acoustic tiles0.70
Heavy curtains0.50
Wood panels0.15
Glass windows0.25
Open window1.00

RT60 Guidelines

0.5-0.8s: Recording studios, broadcast rooms
0.8-1.2s: Lecture halls, conference rooms
1.2-1.8s: Classrooms, offices
1.8-2.5s: Concert halls, opera houses
>3.0s: Churches, cathedrals (poor for speech)

Understanding Reverberation Time

What is Reverberation Time?

Reverberation time (RT60) is the time it takes for sound to decay by 60 decibels after the sound source stops. It's a fundamental parameter in room acoustics that affects speech intelligibility, music quality, and overall acoustic comfort.

Why is it Important?

  • Determines speech clarity and intelligibility
  • Affects music quality and richness
  • Critical for acoustic design of buildings
  • Helps determine need for acoustic treatment

Sabine's Formula

RT60 = 0.163 × V / A

  • RT60: Reverberation time (seconds)
  • V: Room volume (m³)
  • A: Total effective absorbing area (m²)
  • 0.163: Empirical constant for metric units

Effective Absorbing Area

A = Σ(α × S)

Where α is the absorption coefficient (0-1) and S is the surface area (m²) for each material in the room.