๐๏ธ Reverb Time (RT60) Calculator
Sabine equation: RT60 = 0.161 ร volume รท (surface area ร average absorption coefficient)
Enter a room's length, width, and height along with its overall average absorption coefficient (0-1) to calculate the reverberation time (RT60 โ the time for sound to decay by 60 dB), using the Sabine equation widely used in acoustics. Handy for rough estimates of a recording space's acoustics.
How to use
- Enter the room's length, width, and height (meters).
- Enter the room's overall average absorption coefficient (0-1).
- The reverberation time (RT60) is calculated automatically.
How the calculation works
From a roomโs size and the absorption of its surfaces, this tool calculates the reverberation time (RT60): the time for sound to fall by 60 dB (a millionth of its energy) after it stops. It describes how โliveโ a room sounds. Sabine equation: RT60 (s) = 0.161 ร volume (mยณ) รท (surface area (mยฒ) ร average absorption coefficient) The room is treated as a box, and its volume and surface area are worked out from the length, width and height. The absorption coefficient runs from 0 to 1: 0 reflects all sound and 1 absorbs it all.
Worked example
A 4 m ร 5 m ร 2.5 m room, average absorption 0.2 Volume 50 mยณ, surface area 85 mยฒ RT60 = 0.161 ร 50 รท (85 ร 0.2) โ 0.47 s The same room with absorption 0.35 (plenty of curtains, rugs and sofas) RT60 โ 0.27 s
Things to be aware of
- Sabineโs equation is most accurate in fairly live rooms. For rooms with absorption above about 0.3, the Eyring equation is closer to reality.
- Absorption varies with frequency. Low frequencies pass through curtains easily and tend to ring on longer.
- Typical targets: 0.4โ0.6 s for speech and meeting rooms, about 1.5โ2.2 s for concert halls.
FAQ
What's the formula?
The Sabine equation: RT60 (seconds) = 0.161 ร room volume (mยณ) รท total absorption (mยฒ, surface area ร average absorption coefficient). This is a standard approximation widely used in room acoustics.
How do I estimate the average absorption coefficient?
Hard surfaces like tile or concrete have low absorption coefficients (roughly 0.02-0.1), while rooms with lots of soft materials like carpet, curtains, and upholstered furniture have higher ones (roughly 0.2-0.4). Enter a rough estimate based on your room's overall mix of materials.
How should I interpret the result?
A typical home living room comes in around 0.4-0.6 seconds, while recording studio vocal booths often aim for shorter times (around 0.2-0.3 seconds). A longer time indicates a more reflective, "live" space.