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Sound Intensity Measurement Systems: ISO 9614 Equipment Guide

Sound intensity measurement maps the direction and magnitude of acoustic energy flow in a sound field. Required for ISO 9614 sound power determination, building partition transmission loss, and noise source identification — all without requiring a dedicated anechoic chamber. Available from Norsonic Asia for projects across ASEAN, GCC, and South Asia.

The Complete System: Nor150 + Nor1290

  • Nor150 Dual-Channel Analyser — Two fully synchronized, phase-matched input channels for p-p intensity measurement; real-time intensity spectrum, PRI display, and sound power calculation
  • Nor1290 Sound Intensity Probe — IEC 61043 compliant p-p (pressure-pressure) probe; includes three spacer sets: 6 mm (HF), 12 mm (MF), 50 mm (LF); covers 50 Hz – 10 kHz
  • NorReview Intensity Module — intensity maps, surface-integrated sound power, frequency band ranking, and ISO 9614 compliance report

Measurement Quality: Pressure-Residual Intensity Index (PRI)

  • PRI = Lp − LI: pressure level minus intensity level in dB — indicator of measurement environment quality
  • PRI ≥ 10 dB required for engineering-grade measurement per ISO 9614-2
  • PRI ≥ 7 dB required for survey-grade measurement per ISO 9614-1
  • Nor150 displays PRI in real-time — immediate field feedback before saving any data
  • Spacer selection determines frequency range: 6 mm (250–10,000 Hz), 12 mm (125–5,000 Hz), 50 mm (31.5–500 Hz)

Standards Covered

  • ISO 9614-1: Discrete point method
  • ISO 9614-2: Scanning method
  • ISO 9614-3: Precision method
  • IEC 61043: Intensity instruments
  • ISO 3745: Anechoic sound power
  • ISO 16283: Building elements

Sound Power Applications

  • ISO 9614 sound power declaration — machine sound power LW for CE marking, product certification, and purchase specifications
  • HVAC sound power — air handling units, fan coil units, chillers, and cooling towers
  • Industrial machinery — pumps, compressors, gearboxes, and motors in production environments
  • Consumer products — appliances, power tools, and electronics for regulatory labelling

Source Identification Applications

  • Noise source ranking — maps acoustic energy flow to identify which component contributes most to total noise
  • Building partition in-situ transmission loss — without large reverberant source rooms (ISO 16283 complement)
  • Automotive NVH — interior door, roof, and floor panel noise path contribution analysis
  • Machinery diagnosis — identify which bearing, gear stage, or seal is the primary noise emitter

Why Sound Intensity Instead of Sound Power in a Chamber?

  • No anechoic room needed — ISO 9614 can be performed in situ in a factory or lab
  • Source stays in its normal operating environment — no dismounting, transport, or reinstallation
  • Separates source contributions from background noise — valid in moderately reverberant environments
  • Faster and lower cost than building or renting anechoic chamber time

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