1. What is Sabine's Formula?

Sabine's formula is a fundamental equation in architectural acoustics that calculates the reverberation time (RT60) - the time it takes for sound to decay by 60 decibels in an enclosed space. Developed by Wallace Clement Sabine in the early 20th century, it remains a cornerstone of room acoustics design.

2. How Does the Calculator Work?

The calculator uses Sabine's formula:

Where:

• \( RT_{60} \) — Reverberation time in seconds
• \( V \) — Volume of the room in cubic meters (m³)
• \( A \) — Total absorption area in square meters (m²)
• 0.161 — Empirical constant based on the speed of sound in air

Explanation: The formula shows that reverberation time is directly proportional to room volume and inversely proportional to the total absorption in the room.

3. Importance of RT60 Calculation

Details: Proper reverberation time is crucial for speech intelligibility, music quality, and overall acoustic comfort. Different room types require different RT60 values - classrooms need shorter times for clarity, while concert halls need longer times for musical richness.

4. Using the Calculator

Tips: Enter room volume in cubic meters and total absorption area in square meters. Both values must be positive numbers. The total absorption area (A) is calculated by summing the absorption coefficients of all surfaces multiplied by their respective areas.

5. Frequently Asked Questions (FAQ)

Q1: What is the ideal RT60 for different room types?
A: Speech rooms (classrooms, lecture halls): 0.4-0.8 seconds; Music practice rooms: 0.6-1.0 seconds; Concert halls: 1.5-2.5 seconds; Churches: 1.5-3.0 seconds.

Q2: What factors affect absorption area (A)?
A: Different materials have different absorption coefficients. Carpet, curtains, upholstered furniture, and acoustic panels have high absorption, while hard surfaces like concrete, glass, and plaster have low absorption.

Q3: Are there limitations to Sabine's formula?
A: The formula assumes diffuse sound field and uniform absorption distribution. It becomes less accurate in very absorptive rooms (RT60 < 0.3s) or very large spaces with non-uniform absorption.

Q4: How does room shape affect reverberation?
A: While Sabine's formula doesn't directly account for shape, room geometry affects sound distribution. Long, narrow rooms may have different reverberation characteristics than cubic rooms of the same volume.

Q5: Can this formula be used for outdoor spaces?
A: No, Sabine's formula applies only to enclosed spaces where sound reflections dominate. Outdoor spaces lack the reflective boundaries necessary for reverberation as defined by this formula.