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Reverb Time Calculator

Calculate RT60 reverb decay and pre-delay

RT60

0.81 s

Volume

50 m³

Pre-Delay

11.7 ms

Reverberation Time (RT60)

0.81 s

Natural

Volume

50 m³

Absorption

9.9

Pre-Delay

11.7 ms

Absorption Breakdown

Floor6.00 sabins
Walls2.70 sabins
Ceiling1.20 sabins

Recommended Uses

Recording/Vocal Booth0.2–0.4 s
Home Studio/Control Room0.3–0.5 s
Classroom/Conference0.4–0.6 s
Live Music Venue1.0–2.0 s
Concert Hall1.5–2.5 s

What You'll Need

2026 Family Planner Wall Calendar 12"x24"

2026 Family Planner Wall Calendar 12"x24"

$10-$154.5
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VOCOO Digital Kitchen Timer Magnetic Countdown LED

VOCOO Digital Kitchen Timer Magnetic Countdown LED

$10-$164.5
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TC Electronic PolyTune 3 Guitar Tuner Pedal

$60-$804.7
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D'Addario EJ16 Phosphor Bronze Acoustic Guitar Strings Light

$6-$104.7
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Focusrite Scarlett 2i2 3rd Gen USB Audio Interface

$140-$1804.7
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RISEPRO Digital Sound Level Meter 30-130 dB

RISEPRO Digital Sound Level Meter 30-130 dB

$15-$224.3
View on Amazon
2026 Family Planner Wall Calendar 12"x24"

2026 Family Planner Wall Calendar 12"x24"

$10-$154.5
View on Amazon
VOCOO Digital Kitchen Timer Magnetic Countdown LED

VOCOO Digital Kitchen Timer Magnetic Countdown LED

$10-$164.5
View on Amazon

TC Electronic PolyTune 3 Guitar Tuner Pedal

$60-$804.7
View on Amazon

D'Addario EJ16 Phosphor Bronze Acoustic Guitar Strings Light

$6-$104.7
View on Amazon

Focusrite Scarlett 2i2 3rd Gen USB Audio Interface

$140-$1804.7
View on Amazon
RISEPRO Digital Sound Level Meter 30-130 dB

RISEPRO Digital Sound Level Meter 30-130 dB

$15-$224.3
View on Amazon

As an Amazon Associate, we earn from qualifying purchases.

Example Calculations

1Home Studio (4m × 5m × 2.5m, mixed surfaces)

Inputs

Room Length5 m
Room Width4 m
Room Height2.5 m
FloorCarpet (α = 0.30)
WallsDrywall (α = 0.06)
CeilingAcoustic tiles (α = 0.70)

Result

RT600.35 s
Room Volume50.0 m³
Total Absorption22.7 sabins
Pre-Delay (2m wall)11.7 ms

Volume = 5 × 4 × 2.5 = 50 m³. Floor = 20 m² × 0.30 = 6.0. Ceiling = 20 m² × 0.70 = 14.0. Walls = 2×(5×2.5) + 2×(4×2.5) = 45 m² × 0.06 = 2.7. Total A = 6.0 + 14.0 + 2.7 = 22.7 sabins. RT60 = 0.161 × 50 / 22.7 = 0.35 s. Pre-delay = 2 × 2 / 343 × 1000 = 11.7 ms.

2Concert Hall (30m × 20m × 12m, hard surfaces)

Inputs

Room Length30 m
Room Width20 m
Room Height12 m
FloorWood (α = 0.10)
WallsPlaster (α = 0.05)
CeilingPlaster (α = 0.05)

Result

RT607.73 s
Room Volume7,200 m³
Total Absorption150.0 sabins
Pre-Delay (10m wall)58.3 ms

Volume = 30 × 20 × 12 = 7,200 m³. Floor = 600 m² × 0.10 = 60. Ceiling = 600 m² × 0.05 = 30. Walls = 2×(30×12) + 2×(20×12) = 1,200 m² × 0.05 = 60. Total A = 60 + 30 + 60 = 150 sabins. RT60 = 0.161 × 7200 / 150 = 7.73 s. Pre-delay = 2 × 10 / 343 × 1000 = 58.3 ms.

Frequently Asked Questions

Q

What is RT60 and how is it calculated?

RT60 is the time it takes for sound to decay by 60 dB after the source stops. The Sabine equation calculates it: RT60 = 0.161 × V / A, where V is room volume in cubic meters and A is total absorption in sabins.

  • RT60 = 0.161 × Volume / Total Absorption
  • 0.161 is the Sabine constant (metric units)
  • Volume measured in cubic meters (m³)
  • Absorption = surface area × absorption coefficient per material
  • Lower RT60 = drier sound, higher = more reverberant
Room TypeIdeal RT60 (seconds)CharacterTreatment
Recording Studio0.2–0.4 sVery dryHeavy absorption
Home Studio0.3–0.5 sControlledModerate panels
Classroom0.4–0.6 sClear speechCeiling tiles
Concert Hall1.5–2.5 sRich, warmReflective surfaces
Cathedral3.0–8.0 sVery reverberantHard stone walls
Q

How do I calculate reverb pre-delay from room size?

Pre-delay = Distance / Speed of Sound × 1000. For the first reflection: Pre-delay (ms) = (2 × nearest wall distance) / 343 × 1000. A 3-meter wall distance gives about 17.5 ms pre-delay, mimicking natural room reflections.

  • Speed of sound = 343 m/s at 20°C (68°F)
  • First reflection = 2 × nearest wall distance / 343
  • Small room (3 m): ~17 ms pre-delay
  • Medium room (6 m): ~35 ms pre-delay
  • Large hall (15 m): ~87 ms pre-delay
Room SizeNearest WallPre-DelayReverb Feel
Vocal booth1 m5.8 msTight, intimate
Small room3 m17.5 msNatural room
Medium room6 m35.0 msSpacious
Large hall15 m87.5 msGrand, distant
Q

What absorption coefficients should I use for common materials?

Absorption coefficients range from 0 (fully reflective) to 1 (fully absorptive). Concrete is about 0.02, glass 0.04, carpet 0.30, acoustic panels 0.80–0.95. Mix materials to reach your target RT60.

  • Concrete/brick: 0.01–0.05 (highly reflective)
  • Glass windows: 0.03–0.06 (reflective)
  • Plaster/drywall: 0.05–0.10 (slightly absorptive)
  • Heavy carpet: 0.25–0.40 (moderately absorptive)
  • Acoustic foam panels: 0.70–0.95 (highly absorptive)
Materialα (500 Hz)α (1 kHz)Category
Concrete0.020.02Reflective
Glass0.040.03Reflective
Drywall0.060.07Slightly absorptive
Heavy carpet0.300.40Absorptive
Acoustic panel0.800.90Highly absorptive
Q

How does room volume affect reverb time?

Larger rooms have longer reverb times because sound travels farther between reflections. Doubling the volume roughly doubles the RT60 if absorption stays the same. A 50 m³ room with moderate absorption might have 0.5 s RT60, while 200 m³ could reach 2.0 s.

  • RT60 is directly proportional to volume
  • Double volume ≈ double RT60 (same materials)
  • Small bedroom (30 m³): typically 0.3–0.5 s
  • Living room (80 m³): typically 0.5–1.0 s
  • Large hall (2,000 m³): typically 1.5–3.0 s
Q

What is the difference between Sabine and Eyring equations?

The Sabine equation works best for live rooms with low absorption (α < 0.2). The Eyring equation is more accurate for dead rooms with heavy treatment (α > 0.5). For most home studios and live spaces, Sabine is sufficiently accurate.

  • Sabine: RT60 = 0.161 × V / A (simple, widely used)
  • Eyring: RT60 = 0.161 × V / (–S × ln(1 – α_avg))
  • Sabine overestimates RT60 in dead rooms
  • Both converge when average α is low
  • Use Eyring for heavily treated studios

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Last Updated: Mar 25, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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