Reverb Time Designer
Choose a room type for its recommended RT60 range, then get the total absorption your room needs to hit a target (Sabine equation) — plus, if you know your current RT60, the extra panels to get there and a before/after decay curve.
ℹ The targets are recommended ranges from acoustic standards and practice (e.g. ITU-R BS.1116 / EBU Tech 3276 for studios, ANSI/ASA S12.60 for classrooms), not hard limits — rooms and tastes vary. The absorption figure uses the Sabine equation, which assumes a fairly live, diffuse field; it is only approximate in small or very dead rooms (use the Eyring option in the RT60 Calculator there). Targets are mid-band; bass usually decays longer. Material absorption varies by product — verify against datasheets. Metric units; everything runs in your browser.
Idealised energy-decay curve — sound level vs time, reaching −60 dB at the RT60 (green = target, cyan = your current room).
How It Works
Reverberation time (RT60) is how long it takes sound to decay by 60 dB after the source stops. Different spaces want different amounts: a control room or vocal booth should be short and even so you hear the recording, not the room; a concert hall wants a long, enveloping tail. This tool starts from published recommended ranges for your room type, then uses the Sabine equation, RT60 = 0.161 · V / A, to work backwards: for a target RT60 and your room volume V, the total absorption the room must present is A = 0.161 · V / RT60, measured in metric sabins (m²). If you enter your room’s current RT60, it estimates how much absorption you have now and how much more you need, then turns that into a rough number of broadband panels using a typical panel absorption (stated in the result).
Two honest caveats. Sabine assumes sound is diffuse and absorption is spread around the room; in small, lightly furnished, or already very dead rooms it loses accuracy and the Eyring equation does better (the RT60 Calculator offers it). And these targets are mid-frequency values — real rooms almost always decay more slowly in the bass, so plan corner bass trapping separately and expect a gentle low-frequency rise, which is fine for music spaces and worth minimising in critical studios. Use this to set a goal and size your treatment, then confirm by measuring.