Studio Acoustic Calculator
Estimate the reverberation time (RT60) of a recording studio or rehearsal room using its dimensions and surface absorption. Use this when designing or treating a room for optimal acoustic performance.
About this calculator
Reverberation time (RT60) is the time it takes for a sound to decay by 60 dB after the source stops. This calculator uses the Sabine formula: RT60 = 0.161 × V / (S_total × α), where V is the room volume in cubic metres (or scaled for feet), S_total is the total surface area, and α is the average absorption coefficient. Room volume is length × width × height, and total surface area is 2 × (LW + LH + WH). A higher absorption coefficient (closer to 1.0) means more sound-absorbing material on surfaces, resulting in a shorter, drier reverb tail. Ideal RT60 for a vocal booth is around 0.2–0.3 s, while a live room may target 0.4–0.6 s. Knowing your RT60 helps you decide how much acoustic treatment — panels, bass traps, diffusers — to add.
How to use
Suppose your studio is 20 ft long, 15 ft wide, and 10 ft high, with an average absorption coefficient of 0.25. Volume = 20 × 15 × 10 = 3,000 ft³. Total surface area = 2 × (20×15 + 20×10 + 15×10) = 2 × (300 + 200 + 150) = 1,300 ft². Applying the formula: RT60 = 0.161 × 3,000 / (1,300 × 0.25) = 483 / 325 ≈ 1.49 seconds. This is quite reverberant for a studio, suggesting you need more absorptive treatment to bring RT60 below 0.5 s for critical mixing work.
Frequently asked questions
What is a good reverberation time RT60 for a home recording studio?
For a home recording studio used for vocals and acoustic instruments, an RT60 of 0.2–0.4 seconds is generally ideal. Shorter times create a drier, more controlled sound that is easier to mix, since you can always add artificial reverb in post-production. Rooms with RT60 above 0.6 s tend to colour recordings and make it difficult to achieve clarity. Treat your room with broadband absorbers and bass traps to hit the target range.
How does the absorption coefficient affect RT60 calculation?
The absorption coefficient (α) ranges from 0 (perfectly reflective) to 1.0 (perfectly absorptive). In the Sabine formula, RT60 is inversely proportional to α — doubling the average absorption coefficient halves the reverberation time. Common materials have values like: painted concrete ≈ 0.02, carpet ≈ 0.35, thick acoustic foam ≈ 0.7–0.9. Using a weighted average across all surfaces gives a realistic estimate for the whole room.
When should I use the Sabine formula versus the Eyring formula for room acoustics?
The Sabine formula works well for rooms with low to moderate absorption (α below 0.3), which covers most untreated or lightly treated studios. When absorption is high — such as in heavily treated vocal booths or anechoic chambers — the Eyring formula (which uses a logarithmic correction) gives more accurate results. For everyday studio design and treatment planning, Sabine is sufficient and is the industry standard starting point. If your calculated RT60 seems too long despite heavy treatment, switching to the Eyring formula may yield a more accurate picture.