ISO 3382-1:2009

Overview

ISO 3382-1:2009 - "Acoustics - Measurement of room acoustic parameters - Part 1: Performance spaces" specifies standardized methods for measuring reverberation time and other room acoustical parameters in performance spaces (concert halls, theatres, auditoria). The standard defines measurement procedures, required apparatus, coverage (positioning and spatial averaging), data evaluation from impulse responses, and test-report presentation. It is intended for modern digital measuring techniques and for deriving auditorium measures from recorded impulse responses.

Key topics and technical requirements

• Parameters covered: Reverberation time (T), early-decay measures and other room acoustic metrics derived from impulse responses (see annexes for auditorium, binaural and stage measures).
• Measurement methods: Interrupted-noise method and integrated impulse-response method (reverse-time integration of squared impulse responses).
• Equipment:
  • Sound source: near-omnidirectional; Table 1 lists allowable directivity deviations by octave band. Source level must provide sufficient dynamic range (e.g., ≥45 dB above background per band; ≥35 dB if only T is required).
  • Microphones and filters: Omnidirectional microphones; microphone diaphragm preferably ≤13 mm (up to 26 mm allowed with correction). Measurement systems should meet IEC 61672-1 Type 1 and IEC 61260 filter requirements.
  • Recording: No AGC; record length at least 5 s plus expected reverberation time; playback/record speed constraints when using tape-based systems.
• Signal processing: Use of MLS or sine-sweep techniques to derive impulse responses; reverse-time integration to form decay curves.
• Averaging and evaluation: Spatial averaging across receiver positions; evaluation of decay curves (averaging time close to T/30 for exponential averaging, or <T/12 for linear averaging).
• Measurement conditions: Define room occupancy states (unoccupied, studio, occupied) and report environmental data (temperature ±1 °C, relative humidity ±5 %).
• Uncertainty and reporting: Clause on measurement uncertainty, required coverage and standardized statement of results for reproducibility.

Applications

• Objective assessment of auditorium and theatre acoustics for design, renovation and quality control
• Commissioning and verification of acoustic treatments and variable acoustic systems
• Research and comparison of performance-space acoustical quality using standardized metrics derived from impulse responses
• Binaural and musician-focused stage acoustic assessments (annexes B and C)

Who uses this standard

• Acoustic consultants and engineers
• Theatre and venue designers, architects and contractors
• Sound and recording professionals, researchers in room acoustics
• Venue managers and commissioning teams

Related standards

• ISO 3382-2 (Reverberation time in ordinary rooms)
• ISO 3382-3 (planned for open-plan spaces)
• IEC 61672-1 (sound level meter specifications) and IEC 61260 (octave and fractional-octave filters) - normative references

Keywords: ISO 3382-1:2009, reverberation time, room acoustic parameters, performance spaces, impulse response, auditorium acoustics, acoustic measurement.