www.microflown.com

Microflown multi purpose sound intensity arrays for Vehicle Acoustics.

Microflown Technologies (www.microflown.com) from the Netherlands develops and markets highly innovative testing solutions for engineers working in the field of Noise, Vibration and Harshness.

It is the only company in the world manufacturing a dedicated sensor (=Microflown) measuring the acoustic particle velocity, the vector value that describes a sound field completely together with the well known scalar value sound pressure.

Many new possibilities are discovered to measure noise and vibration problems more accurate and faster than before.

As such, close to a vibrating surface, the Microflown scanning probe measures the structural velocity in a non contact manner. It offers an alternative to scanning laser vibrometers and accelerometers.

The combination of Microflown sensors with sound pressure transducers results in a range of one (PU) and even three (USP) dimensional sound probes.

The PU probes are extremely small and truly broad banded covering the entire audio range. Measurements with PU probes are not susceptible to reflections and background noise and the most advanced probes resist high temperatures up to 300 degrees Celsius.

Applications of this Microflown based technology include:

Real time and broad banded intensity and velocity based acoustic camera

Sound source localization techniques have only been based upon the measurement of sound pressure values captured at a certain distance from the actual surface of the test object.

With Microflown based PU mini sound intensity probes it is possible to directly measure all required acoustic quantities now directly. The visualization software is only the colour mapping of the quantities, allowing real time and truly broad banded measurements for acoustic hot spot finding based upon sound intensity and particle velocity measurements.

End of line acoustic control in a manufacturing environment with background noise

Apart from product development purposes, Microflown based testing technology is also used in a manufacturing environment with background noise for acoustic end of line control, replacing scanning laser vibrometers and accelerometers.

Since Microflown sensors are not susceptible to background noise, they perform where sound pressure transducers are not feasible, since the signal to noise ratio is far better for velocity signals close to the testing object

Vehicle interior panel noise contribution and transfer path analysis

The acoustic comfort analysis of a car driver requires the measurement of vibrations (for lower frequencies) and sound intensity (for higher frequencies) for a wide range of interior panels.

Use of Microflown PU probes solves all combines all these measurements in one single transducer solution, measuring at the same time (indirectly) the structural velocity, sound pressure and sound intensity.

Testing under realistic driving conditions is possible now with a PU mini array up to 192 data acquisition channels.

A new industrial standard emerges for testing whilst driving.

Broad banded, all angle, in situ acoustic reflection measurements

Microflown PU-probe probes allow fast and non destructive measurements, providing broad banded results for all angles of incidence.

The surface impedance method uses a ‘piston in a sphere’ calibrator. A time window technique is applied to make it possible to calibrate the PU probe out in the field instead of in an anechoic room.

The mirror source method uses a miniature monopole sound source that is put close to an acoustic absorbing surface. A Microflown is placed close to the point source in such way that its sensitive direction is aiming at the mirror source and its non-sensitive direction is pointing towards the monopole sound source. It will therefore only ‘see’ the mirror source. With this method it is possible to measure the broad band absorption in confined placed like inside a car.

Microflown Technologies
PO Box 300
6900 AH Zevenaar
The Netherlands

W: www.microflown.com
E: info@microflown.com
T: +31 316 581490
F: +31 316 581491