Reverb Time Calculator
Calculates reverberation decay time (RT60) for a room using its volume and total acoustic absorption. Use it when designing studios, concert halls, or any space where echo control matters.
About this calculator
Reverberation time, or RT60, is the time in seconds it takes for a sound to decay by 60 dB after the source stops. It is calculated using Sabine's formula: RT60 = 0.161 × (V / A), where V is the room volume in cubic metres and A is the total absorption in sabins (the sum of each surface area multiplied by its absorption coefficient). A larger room with little soft furnishing will have a long, boomy reverb, while a smaller, heavily treated room will sound dry and dead. Ideal RT60 values vary by use: roughly 0.3–0.5 s for recording studios, 1.5–2.0 s for concert halls, and 0.6–1.0 s for home theatres. Understanding RT60 helps engineers select acoustic treatment materials and quantities to hit a target decay time.
How to use
Suppose you have a recording studio with a room volume of 80 m³ and a total absorption value of 25 sabins. Plug the values into Sabine's formula: RT60 = 0.161 × (80 / 25) = 0.161 × 3.2 = 0.515 seconds. This means sound will decay 60 dB in about half a second — on the dry side, which is typical for a vocal booth or tracking room. If the result is too long, add more absorptive panels to increase the absorption value and reduce RT60.
Frequently asked questions
What is a good reverberation time for a home recording studio?
For a home recording studio, an RT60 between 0.3 and 0.5 seconds is generally considered ideal. Shorter reverb times keep recordings clean and free of room coloration, making it easier to add artificial reverb in post-production. Rooms that are too dead (below 0.2 s) can feel uncomfortable to perform in and may cause ear fatigue. Aim for the lower end of that range for vocal booths and the higher end for live instrument rooms.
How does room volume affect reverberation time?
Room volume has a direct proportional effect on RT60: doubling the volume doubles the reverb time if absorption stays constant. This is why large, hard-surfaced rooms like cathedrals have very long reverb tails lasting several seconds, while a small bedroom sounds much drier. When designing a space, engineers balance volume against the amount and type of absorptive material installed. Increasing absorption is the most practical way to shorten RT60 in an existing room.
What is the difference between absorption coefficient and total absorption in Sabine's formula?
The absorption coefficient (α) is a dimensionless value between 0 and 1 that describes how much sound energy a specific material absorbs at a given frequency — 0 means perfect reflection, 1 means perfect absorption. Total absorption (A), measured in sabins, is calculated by multiplying each surface area by its absorption coefficient and summing all surfaces in the room. Sabine's formula uses total absorption A, not the individual coefficient of a single material. In practice, different surfaces (carpet, glass, acoustic foam) each contribute their own α × area product to the total.