Exploring the paths of sound
What problem are we solving?
Noise often “leaks” from unexpected places: a joint, a service opening, a window frame, a machine enclosure. Even a well-built wall loses much of its insulation because of one weak spot.
A sound level meter shows the overall level, but does not tell you where the sound comes from. With a sound intensity probe we measure how much sound energy passes through each area and in which direction – and that is how we find the weak spots.
Standards and status of the measurement
The method is sound intensity – following the principles of EN ISO 15186-1 (sound insulation) and EN ISO 9614 (sound power of sources).
The measurement is an engineering assessment for diagnostic purposes and is not accredited. If you need an official test report, see Measurements and diagnostics.
Equipment: What do we use to measure?
We measure with Sonocat (Demcon) – a sound intensity probe.
- It is not an acoustic camera and does not take a “picture” of the noise. The probe is placed at points across the surface and measures intensity – how much energy passes and in which direction.
- Condition: steady noise. Pink noise from a loudspeaker on the other side of the partition, or a machine running continuously in one mode.
- With short or fluctuating noise (impacts, switching on and off) the method does not give reliable results.
Practical use
The method is useful for:
- Weak spots in partitions – joints, sockets, service openings, window frames, ceilings. We measure with a loudspeaker on the other side.
- Machines and equipment in steady operation – which side of the enclosure or which part radiates most, and what the sound power of the source is.
- Checking built partitions and enclosures – before and after repair.
Process and Analysis: What Does the Client Get?
Technical report with:
- distribution of sound intensity over the measured areas – table and diagram by point;
- frequency analysis of the weak spots – at which frequencies they leak;
- sound power of the source, when that is the goal;
- proposed measures – what to seal, line or replace.
Frequently Asked Questions
Can noise through the ceiling be traced?
Yes, if the source is steady. We measure across the surface of the ceiling and the walls and compare how much energy passes through each. This shows whether the noise comes through the slab or by a flanking path.
Does the machine have to stop during the test?
No – the opposite. The machine has to run continuously in the same mode. If it runs in cycles or with impacts, we first assess whether the method is suitable.
Can a whole facade be measured at once?
Not at once. The probe measures point by point, so selected areas are measured – around windows, joints and junctions. On a large facade we first identify the suspicious spots.
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