Acoustic CameraAdvanced Sound Measurement & Analysis
The Sorama sound camera is a state of the art sound imaging tool.The sound camera coupled with the specialist software allows the user to perform incredibly accurate measurements of their problematic sound source.
The camera consists of 1024 high quality MEM microphones in an array. The 1mm resolution provides precise detail as to the noise source and propagation behaviour.
There are two main visualisation formats: beamforming and holography. The default measurement is sound pressure, although sound intensity and particle velocity can also be measured.
Measurements can be taken in a matter of minutes, obtaining a large amount of information in a short time. This allows the engineers to gather high quality information quickly and accurately.
See The Camera In Action
Beamforming – Source Localisation
The beamforming measurement is a far field overview of the measurement object.
It is used to pin point the most troublesome areas within the measurement object so that more detailed studies can be performed in the problematic locations.
Due to the fact that the sound camera is placed further away from the source (normally a few metres) the resolution is lower than the holography measurements.
The effective frequency range of this technique is 1kHz and above. An immediate live capture video is created showing clearly in colour the sound propagation across the medium. The red sections show the areas of high sound pressure, yellow depicts areas where the sound pressure is high but not necessarily problematic and the blue indicates areas of low sound pressure. A scale underneath the picture shows the exact sound pressure in Pascals for each gradient of red to blue.
Near Field Holography
The holography measurements provide incredibly accurate and precise sound imagery.
The sound camera is placed 3-20cm from the measurement object, providing imaging accuracy of up to half a millimetre.
With this technique the exact source of noise can be determined and dealt with.
As with beamforming, the areas that show red on the source are the areas of high sound pressure.
Frequently Asked Questions
What are the main benefits of using an acoustic camera?
This type of equipment is that it allows both beamforming measurements (live acoustic camera work) and near field holography (detailed up close analysis). The software allows for animated maps of the wave motion for the near filed work and it can display this in a 3 dimensional format. This combination of abilities makes the camera a very powerful noise source identification tool but also one that can provide real insight into the source of noise generation.
Does it speed up the process of testing both on site and in the laboratory?
This very much depends on the application. There was a case where a problem noise from a machine was eluding our client for months despite having experience in acoustics and the camera was able to identify the source within a morning which led to a straight forward fix. On the other hand, another client used the camera to conduct a comprehensive sweep across every inch of a source, in multiple operating conditions, to develop an in-depth understanding of the unit. This can lead to a very large amount of data to be processed.
What specific noise measurements will it identify?
The camera is designed to provide qualitative data, in the form of noise maps, rather than the quantitative data a sound meter would provide. Beamforming is a good way of finding the ‘hotspots’ over a large area quickly but it is limited to a relatively high frequency range. Near field holography can measure a very broad frequency range and can map the results in terms of pressure, particle velocity or intensity but is used very close to the noise source and work best on relatively flat structures.
What are the main benefits for vehicle manufacturers?
Vehicles are complex noise sources that work at different operating conditions and noise source identification can be challenging. The mapping techniques of the camera are useful for identifying weak points and hotspots but they also can provide insight into the behaviour of the sound. This is done by using the phase data (wave motion) to animate the maps to show how the sound propagates from a structure.
What can be tested using this camera?
A wide range of noise sources can be tested. Ventac have typically used it to test passenger vehicles, industrial vehicles, heavy machinery and electronic equipment but this is by no means an exhaustive list and we are consistently surprised by the range of noise problems our customers have.