Sound Intensity Buying Guide
Sound intensity is the flow of sound energy per unit area — a vector quantity that reveals direction. It lets you measure sound power and locate sources accurately in real-world noisy environments without an anechoic chamber, making it indispensable for machinery compliance testing, flanking path analysis, and source ranking.
Sound Power (ISO 9614)
Determine the sound power of machinery and products for CE marking without anechoic facility.
Source Identification
Rank individual components by their contribution to overall noise and prioritise noise control.
Transmission Path Analysis
Measure flanking transmission through walls, floors, and facades in-situ for building acoustics.
Choosing the Right Spacer for the Nor1290 Probe
The spacer between the two microphones determines the valid frequency range of the measurement. The Nor1290 kit includes all three standard spacers.
Required Equipment
Sound intensity requires a dual-channel analyser — a single-channel SLM cannot perform intensity measurements.
Nor1290
Sound intensity probe kit
Phase-matched mic pair + 6/12/50 mm spacers
Nor150
Dual-channel Class 1 analyser
Required for intensity — dual input, intensity firmware
Nor850 SI
Sound Intensity software (ISO 9614)
Discrete points + scanning methods, auto-report
SI with Nor150
Complete intensity solution
Analyser + probe + software bundle
Frequently Asked Questions
What is sound intensity and why measure it instead of sound pressure?
Sound intensity is the flow of sound energy per unit area (W/m²), measured as a vector quantity with both magnitude and direction. Unlike sound pressure, which is a scalar, intensity measurements can distinguish between sound coming from the source under test and background noise from other directions. This allows you to measure sound power and locate noise sources accurately in noisy factory or field environments without needing an anechoic chamber.
Which ISO standard applies to sound intensity measurements?
Sound power determination using sound intensity is covered by ISO 9614: ISO 9614-1 (discrete point method — simpler setup), ISO 9614-2 (scanning method — faster for larger or complex sources), and ISO 9614-3 (precision scanning — highest accuracy). The method you choose depends on source size, required accuracy grade, and time available. Nor850 Sound Intensity software supports all three methods.
How do I choose the right spacer for the Nor1290 intensity probe?
The spacer determines the useful frequency range. Use 6 mm for 250 Hz–10 kHz (high-frequency work, small sources), 12 mm for 125 Hz–5 kHz (most general applications — the default choice), and 50 mm for 31.5 Hz–1.25 kHz (low-frequency analysis, large machinery, HVAC). The Nor1290 kit includes all three spacers. For building acoustics flanking transmission path analysis, the 12 mm spacer covers the full ISO 16283 frequency range.
Do I need a special analyser for sound intensity, or can any Class 1 SLM be used?
Sound intensity requires a dual-channel analyser that can cross-correlate two phase-matched microphone signals in real time. The Nor150 with intensity firmware is purpose-designed for this. Standard single-channel SLMs like the Nor145 cannot perform intensity measurements. The Nor150 accepts the Nor1290 probe directly via its dual-input connector and runs the intensity calculation on-board.
What applications use sound intensity measurements?
Key applications include: (1) Sound power determination of machinery and products per ISO 9614 — required by CE/EU machinery directive for noise emission labelling; (2) Noise source identification and ranking on complex assemblies (automotive, HVAC, industrial equipment); (3) Sound transmission path analysis through building partitions and façades; (4) In-situ sound insulation testing of built assemblies. Sound intensity is particularly valuable when background noise is high and separating sources is critical.