Sizing the Absorbing Surface to Reach RT60

RT60 represents the reverberation time — the time it takes for sound to decay by 60 dB after the source stops. It defines how clear, comfortable or lively a room sounds.

Why calculate absorption area?

Acoustic comfort depends on controlling RT60. Too long = echo and fatigue. Too short = dull and unnatural. The right value depends on the room volume and its use.

Parameters to consider

  • Room volume (m³)
  • Reflective surfaces: walls, ceiling, floor
  • Existing materials and their absorption coefficients
  • Target RT60 depending on activity (office, restaurant, etc.)

Calculation approach

The goal is to determine how much absorbing surface is needed to reach the target RT60. Sabine’s formula is used : RT60 = 0.16 × V / A, where V is room volume and A is total absorption. Adjustments are made for surface distribution and materials.

Verification

Measure or simulate the current reverberation before adding treatment. Try the Tester / Acoustic tool to estimate improvements and compare results.

Reference comfort levels

  • Offices / meeting rooms : RT60 ≈ 0.77 s
  • Restaurants : RT60 ≈ 0.55 s
  • Conference / listening rooms : RT60 ≤ 0.5 s

See real examples on Inspiration or get expert guidance through Contact.

Oct. 17, 2025, 2:01 p.m.