Acoustic Standards Cheat Sheet — Quick Reference for Audio Professionals

Why Every Audio Professional Needs a Standards Cheat Sheet

Audio measurement standards are dense, expensive documents. A single standard can run over 100 pages and cost over $200. Most engineers only need the key values — the thresholds, the tolerances, the required measurement parameters. This cheat sheet extracts exactly those values from 12 major standards so you can quickly look up what you need in the field.

Sound Level Measurement Standards

IEC 61672-1 — Electroacoustics: Sound Level Meters

• Class 1: ±1.1 dB at reference frequency (1 kHz). Required for enforcement.
• Class 2: ±1.4 dB at reference frequency. Suitable for surveys and commissioning.
• Frequency weightings: A (clause 5.4), C (clause 5.5), Z (clause 5.6)
• Time weightings: Fast (125ms), Slow (1000ms), Impulse (35ms attack / 1500ms decay)
• Frequency range: 20 Hz to 20 kHz (Class 1), 20 Hz to 8 kHz minimum

OSHA 1910.95 — Occupational Noise Exposure

• PEL: 90 dBA TWA (8 hours), 5 dB exchange rate
• Action Level: 85 dBA TWA — triggers hearing conservation program
• Peak: 140 dBC maximum
• Monitoring: annual audiometric testing required above action level

ISO 9612 — Noise at the Workplace

• LEX,8h: normalized A-weighted 8-hour exposure level
• 3 dB exchange rate (vs. OSHA 5 dB)
• Three measurement strategies: task-based, job-based, full-day
• Uncertainty calculation per GUM (expanded uncertainty U at 95% confidence)

Room Acoustics Standards

ISO 3382-1 — Room Acoustics: Performance Spaces

• Parameters: T20, T30, EDT, C50, C80, D50, Ts, G
• Minimum source positions: 2. Minimum receiver positions: 3 per source.
• INR requirements: 35 dB for T20, 45 dB for T30
• Regression fit: r² > 0.99 for valid T20/T30

ISO 3382-2 — Room Acoustics: Ordinary Rooms

• Simplified method with fewer positions. Minimum 2 source × 3 receiver.
• Engineering method: more positions for lower uncertainty
• Applicable to offices, classrooms, hospitals, residential

ANSI/ASA S12.60 — Classroom Acoustics

• RT60 maximum: 0.6s (rooms under 283 m³) at 500-2000 Hz
• Background noise: 35 dBA maximum (unoccupied)

Speech Intelligibility Standards

IEC 60268-16 — Speech Transmission Index

• STI range: 0 (unintelligible) to 1 (perfect)
• Rating scale: Bad (<0.30), Poor (0.30-0.45), Fair (0.45-0.60), Good (0.60-0.75), Excellent (>0.75)
• STIPA method: Table F.1 defines 14 modulation frequencies across 7 octave bands
• Male speech weighting: Table 4 (clause 5.3)

Sound Insulation Standards

ISO 717-1 — Airborne Sound Insulation Rating

• Rw: weighted sound reduction index (reference curve shifted to measured data)
• Spectrum adaptation terms: C (pink noise) and Ctr (traffic noise)
• Maximum 32 dB total unfavorable deviation

ASTM E413 — STC Rating

• STC: Sound Transmission Class (North American equivalent to Rw)
• 8 dB maximum single deficiency per 1/3 octave band
• 32 dB total deficiency limit

Speaker and System Standards

IEC 60268-5 — Loudspeakers

• Sensitivity: SPL at 1m with 2.83V input (averaged across rated frequency range)
• Frequency range: -10 dB points relative to sensitivity
• THD measurement: H2 through H5 per clause 24

AES-2id — Recommended Practice for Audio Systems

• Transfer function measurement recommendations
• Coherence-weighted measurements for system alignment

All Standards Implemented in SonaVyx

SonaVyx implements measurement tools for all 12 standards listed above — entirely in your browser. Open the Measurement Workspace to get started with any measurement type. Every result page links to the relevant standard reference.