How to Measure Room RT60 Accurately

What Is RT60?

RT60 is the time for sound to decay by 60 decibels after the source stops. A recording studio control room targets 0.2-0.4 seconds, while a concert hall might aim for 1.8-2.2 seconds.

Tools You Need

• Measurement mic: Calibrated omnidirectional condenser (Behringer ECM8000 or Dayton Audio EMM-6)
• Audio interface: Any with phantom power
• Software: Room EQ Wizard (REW, free)
• Sound source: Studio monitors

Measurement Steps

Place the mic at the listening position at ear height. Generate a logarithmic sine sweep (20 Hz to 20 kHz, 10+ seconds). Record the response. The software extracts RT60 from the impulse response across octave bands.

Common Pitfalls

• Background noise must be 35+ dB below test signal
• Take 4-6 measurements and average (single position is biased)
• In small rooms, use T20 or T30 extrapolation instead of full RT60

Target RT60 Values

• Studio control room: 0.2-0.4s
• Home theater: 0.3-0.5s
• Podcast studio: 0.15-0.25s
• Concert hall: 1.8-2.2s

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