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Near-field Acoustic Camera

Near-field Acoustic Camera



The Near Field Acoustic Camera allows localisation and real-time analysis of non-stationary noises such as squeaks, rattles and clicks. Unlike traditional techniques, the array of sensors does not only capture sound pressure, but the Near Field Acoustic Camera measures also directly the particle velocity. Hence, the Near Field Acoustic Camera yields an accurate particle velocity map in the full audible frequency range, while maintaining a dynamic range and an unmatched spatial resolution.


  • Frequency range 20Hz – 10kHz
  • Large dynamic range | up to 45 dB
  • High, frequency-independent, spatial resolution
  • Applicable in (real) operating environments
  • Visualization of transients & non-stationary sound fields
  • Extensive order analysis tools


  • Noise source identification
  • Noise ranking
  • Squeak & Rattle noise
  • Vehicle acoustics
  • Component testing
  • Powertrain nvh
  • Troubleshooing
  • Benchmarking


The Microflown Acoustic Camera is a flexible and versatile all-in-one box solution, which allows for real-time localisation and analysis of non-stationary noises such as squeaks, rattles and clicks. All that can be done either by a direct sound field visualisation technique or by employing acoustic holography algorithms for near-field sound reconstruction. Microflown probes enable the direct measurement of particle velocity. Thanks to this unique property, the localisation task can be performed in any measurement environment, and in a broad frequency range (20 Hz -10 kHz). Making the system unique in the capability of accurate sound source localisation for low frequencies.

It is a perfect tool for diagnostics and localisation of non-stationary noise sources from the product development stage til the end of line quality control. The physical properties of particle velocity and the design of the sensors make our systems less susceptible to background noise. Therefore accurate sound intensity and sound power results can be obtained in situations with a high sound pressure over sound intensity ratio (P/I index). This unique feature makes this system a superb engineering tool for troubleshooting, benchmarking, or quality control of all kinds of objects in-situ. In practice, there are many cases where anechoic conditions are not applicable, for instance in an industrial manufacturing environment or a car interior. The Acoustic Camera is a solution which does not require any compromise when taking measurements even in acoustically challenging environments.

Near Field Acoustic Holography (NAH)

There is an optional second processing method, next to the standard DSV, which is based on the Near Field Acoustic Holography (NAH). The NAH allows for finer interpolation and greater resolution in the obtained sound field visualisations. Furthermore, the NAH method allows for the extension of the measured plane. Thanks to this feature, the sound field can be calculated closer, or further away from the actual measured plane. Both methods can display absolute values for sound pressure, particle velocity, sound intensity, or sound power. The Acoustic Camera array, thanks to the presence of two sound field visualisation techniques, can be used either as a planar array, or a scattered array with sensors positioned randomly around the surface of the studied noise source. This feature has significant consequences for how the equipment can be utilised. If you require a quick measurement, then a planar array coupled with the NAH processing will deliver the best results in a short time frame. However, if you need a detailed examination of a complex problem in a noisy environment, then positing your sensor close to the measured surface, while using the DSV processing, would yield the best results.

Order Tracking and Analysis

The system is equipped with an extensive order analysis module. It allows to track the rotational orders both with and without a tacho sensor. The Order Tracking Module is a perfect tool for studying rotating machinery, as it allows to analyse the frequency content of a signal with respect to the speed of rotation. What makes this module unique is the capability to extract the rotational orders without the necessity to record the RPM signal. Order extraction is done with just a few mouse clicks. You only need to define and highlight a known order in the spectrogram of a recorded sound signal. An efficient algorithm will then track the order and translate it into a tacho signal. The tacho signal synthesised this way, can now be used to determine the distribution of any other orders of your choice, in a simple and easy to understand ordergram.

Sound Power Measurements

Thanks to the unique features of the Microflown sensor, sound power measurements can now be done in-situ and in acoustically challenging environments. The Acoustic Camera is equipped with PU probes. Each probe measures sound pressure and particle velocity at the same point in time and space. Sound intensity is calculated by taking the time-averaged product of both quantities. If the measured area is known, the software can visualise the distribution of sound power in realtime in a broad frequency range (20 Hz – 10 kHz). Furthermore, the unique properties of particle velocity reduce the requirements for the acoustic treatment of the measurement environment. Accurate sound power results can now be obtained in-situ, or in industrial manufacturing environments. Benchmarking and quality control has never been easier.

  • FFT
  • RPM – Tacho input
  • Order tracking
  • Overall vs Orders
  • Linear, Irregular and scatterd arrays
  • Audio and Video recording
  • Sound pressure dB & dBA
  • Particle velocity
  • Sound intensity
    • Active
    • Reactive
    • Possitve
    • Negative
  • Narrow Band
  • Octave
  • 1/3 Octave
  • 1/12 Octave
  • Extraction of the colormap tools
  • Frequency filtered playback of audio
  • Frequency and Time domain
  • Auto range
  • Import of Universal files (.unv)
  • Export to Time Files, MS Excel  & TXT
  • Export video to avi
  • Report function


Microflown near field acoustic camera datasheet