RT60 Reverb Time Calculator
Estimate room reverberation time (RT60) using the Sabine and Eyring equations. Enter your room dimensions and average absorption values to get practical acoustic guidance for speech, recording, music, and home listening.
What Is Reverb Time (RT60)?
Reverb time, usually written as RT60, is the time it takes for a sound to decay by 60 dB after the source stops. In plain terms, it describes how “live” or “dead” a room sounds. A long RT60 feels echoey and spacious, while a short RT60 feels dry and controlled.
If you are tuning a home studio, classroom, church, office, podcast room, or listening room, RT60 is one of the most useful metrics for acoustic quality.
How This Reverb Time Calculator Works
This reverb time calculator estimates RT60 from room geometry and material absorption. It reports two common models:
- Sabine equation (great for most practical estimates)
- Eyring equation (often better when average absorption is higher)
Sabine: RT60 = K × V / A
Eyring: RT60 = K × V / (-S × ln(1 - ᾱ))
Where V is room volume, A is total absorption (sabins), S is total surface area, and ᾱ is average absorption coefficient. The constant K is 0.161 (metric) or 0.049 (imperial).
Inputs You Need
- Room dimensions: length, width, and height
- Average absorption coefficients: floor, ceiling, and walls (0 to 1)
- Additional absorption: optional sabins for occupants and furnishings
Typical RT60 Targets by Room Type
These are rough design ranges used by many acoustic consultants:
- Vocal booth / podcast booth: 0.20–0.45 s
- Small recording control room: 0.25–0.50 s
- Home theater: 0.30–0.60 s
- Classroom: 0.40–0.70 s
- Living room: 0.40–0.80 s
- Small hall / rehearsal room: 0.80–1.30 s
- Church / large worship space: 1.50–3.50 s
How to Improve Room Reverberation
If RT60 Is Too High (Too Echoey)
- Add broadband absorption panels to first reflection points.
- Use thicker ceiling treatment or acoustic cloud panels.
- Add rugs, upholstered furniture, curtains, and bookshelves.
- Place bass traps in corners to control low-frequency decay.
- Break up large reflective surfaces with diffusion.
If RT60 Is Too Low (Too Dead)
- Remove some absorption, especially from mid/high frequencies.
- Introduce diffusers to keep life without adding harsh reflections.
- Use mixed surfaces instead of fully soft treatment everywhere.
Practical Notes
RT60 calculators are design tools, not substitutes for in-room measurements. Real spaces vary by frequency, occupancy, humidity, and furniture layout. For accurate tuning, measure the room with a calibrated microphone and acoustic software after treatment changes.
FAQ
What is a good RT60 for speech clarity?
For speech-heavy spaces like classrooms, meeting rooms, and podcast setups, a common target is around 0.4 to 0.8 seconds (often lower for close-mic recording).
What is a good RT60 for music?
It depends on style and room size. Small practice and project spaces often feel good around 0.6 to 1.2 seconds. Performance spaces may intentionally run longer.
Why do Sabine and Eyring results differ?
Sabine assumes relatively low average absorption and can overestimate decay in highly treated rooms. Eyring handles higher average absorption more realistically, so both values are useful context.
Can I use feet instead of meters?
Yes. Switch to imperial units in the calculator. The proper constant is automatically used.