Reverberation Time Measurement Grading

ISO 3382-2 Measurement Accuracy Levels for Room Acoustics


Did you know the SoundAdvisor™ Sound Level Meter with Room Acoustic tools reports your reverberation time measurement grade, or level of measurement accuracy, according to ISO 3382-2 standards? Looking for a different grade? The meter will provide information on how to get there.

The Reverberation Time measurement levels are survey, engineering, and precision. Various parameters go into measurement grading, including excitation method, number of source and microphone measurement locations, bandwidth, and number of measurements at each location. A basic introduction to the measurement grades can be found below. SoundAdvisor Sound Level Meter offers built-in measurement configurations for each level, simplifying meter setup. For a complete understanding, please refer to the ISO 3382-2 standard.

Measurement GoalIs there the proper amount of sound absorption for noise control?
Compliance with ISO 10052
Does the room meet the specified requirements for reverberation time or room absorption?
Compliance with ISO 140
High measurement accuracy is required
Source/Microphone Combinations2612
Source positions≥ 1≥ 2≥ 2
Microphone positions≥ 2≥ 2≥ 3
Number of decays in each position
(Interrupted Noise Method)
Measurement Method
Impulse Response or Interrupted NoiseInterrupted NoiseInterrupted Noise
SoundAdvisor Predefined Setup*RT_Surv (Impulse Response Method)
Minimum Frequency Range (1/1 octave measurement)250 Hz to 2 kHz125 Hz to 4 kHz125 Hz to 4 kHz
Minimum Frequency Range (1/3 octave measurementN/A100 Hz to 5 kHz)100 Hz to 5 kHz
Nominal accuracy (1/1 octave bands) < 10%< 5%< 2.5%
Nominal accuracy (1/3 octave bands)N/A< 10%< 5%

* ASTM2235 predefined setup also available for compliance to ASTM 2235 standard. No grade is associated with this measurement.