Reverberation Time Calculator
Enter room volume and total absorption to compute reverberation time RT60=0.161·V/A. V=100 m³, A=10 m² Sabine → T=1.61 s. Concert halls target 1.8–2.2 s, speech 0.8–1.2 s.
Input Data
Results
At a glance:Reverberation time (RT60): the time for the sound-pressure level to decay by 60 dB after the source stops. Sabine's formula RT60=0.161·V/A, where V is room volume (m³) and A=ΣαᵢSᵢ total absorption (m² Sabine, αᵢ the surface absorption coefficient 0–1, Sᵢ the area). The Sabine constant 0.161 is c/(24·ln10) with c=343 m/s. History: in 1900 Sabine studied the echo problem of Harvard's Fogg Art Museum lecture hall and found RT60 is proportional to volume and inversely proportional to absorption, founding architectural acoustics. Classic example: V=100 m³, A=10 m² Sabine → T=1.61 s (ideal for a lecture hall). Applications: (1) concert halls — best RT60 1.8–2.2 s; (2) lecture halls — 0.8–1.2 s for speech clarity; (3) recording studios — 0.3–0.6 s to avoid coloration; (4) theatres — 1.0–1.5 s; (5) classrooms — 0.6–0.8 s.
Formula
Sabine: RT60 = 0.161·V / A
Total absorption: A = Σ(αᵢ·Sᵢ) (m² Sabine)
Sabine constant: 0.161 = c/(24·ln10), c=343
Absorption coeff: α = 1 − |r|² (r reflection coeff)
A for T=1s: A = 0.161·V
$$RT_{60} = \frac{0.161\,V}{A}, \quad A = \sum_i \alpha_i S_i, \quad 0.161 = \frac{c}{24\ln 10}$$How to Use
- Enter room volume V (m³) and total absorption A (m² Sabine).
- The tool gives RT60=0.161V/A, the A needed for T=1 s and the V/A ratio.
- Common: V=100, A=10 → T=1.61 s; hall V=10000, A=900 → T≈1.79 s.
Case Studies
Boston Symphony Hall acoustics
Boston Symphony Hall (1900), designed by Sabine himself, was the first scientifically designed concert hall. Volume V=18000 m³, seats 2625.
Sabine target RT60=1.8 s (mid 500–1000 Hz); measured empty 2.4 s, full 1.85 s (audience absorbs strongly). Audience absorption ≈0.5 m²/person × 2625 = 1310 m² Sabine.
A shoebox long-rectangle (2:1) creates lateral reflections and rich early sound — still the gold standard. Vienna Musikverein (1870) ranks with Boston among the world's top three.
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.