RT60 is the time it takes for sound in a room to decay by 60 dB after the source stops. It is the standard measure of how "reverberant" or "live" a room sounds. A concert hall might have an RT60 of 1.5-2.5 seconds, while a recording studio control room typically targets 0.3-0.5 seconds.

What is the difference between Sabine and Eyring?

The Sabine equation assumes low absorption and works well for live rooms (average absorption coefficient below 0.2). The Eyring equation accounts for high absorption and gives more accurate results for well-treated rooms. For very absorbent rooms, Sabine overestimates the RT60.

What RT60 should I aim for in a home studio?

For a home studio control room, aim for an RT60 of 0.3-0.5 seconds across the mid and high frequencies. Bass frequencies will naturally have a longer decay time. Professional studios often aim for a flat decay curve using calibrated bass trapping.

What is the absorption coefficient?

The absorption coefficient (α) ranges from 0 (perfectly reflective) to 1 (perfectly absorptive). Concrete walls have α ≈ 0.02, plasterboard ≈ 0.05, carpet ≈ 0.30, and thick acoustic foam ≈ 0.80. The average α for the room is the total absorption divided by the total surface area.

AudioCalcs

Reverb Time Calculator — RT60 Sabine & Eyring

Calculate RT60 reverberation time using the Sabine and Eyring equations. Enter room dimensions and absorption.

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How We Calculate This

Sabine Equation

RT60 = 0.161 × V / A

Where V is volume in m³ and A is total absorption in sabins (m²).

Eyring Equation

RT60 = 0.161 × V / (-S × ln(1 - α))

Where S is total surface area and α is the average absorption coefficient.

Total absorption A = S × α (surface area multiplied by average absorption coefficient). The constant 0.161 assumes the speed of sound is 343 m/s at 20°C.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard formulas. Always verify results for critical applications.