RT60

Definition

RT60 (Reverberation Time 60) is the standard measurement for how long it takes reverb to decay by 60 decibels after the source stops. It's the technical term for what's commonly called "decay time."

Why 60dB?

A 60dB reduction represents a drop to one-millionth of the original sound pressure level, making it effectively inaudible in most practical situations.

Measuring RT60

Professional measurement involves:

1. Playing a known signal in the space
2. Recording the decay
3. Analyzing the time for 60dB reduction

Typical RT60 Values

• Recording studio: 0.2-0.5s
• Living room: 0.4-0.7s
• Small concert hall: 1.0-1.5s
• Large concert hall: 1.8-2.2s
• Cathedral: 3-8s

Related Terms

• Decay Time
• Reverb Tail
• Absorption