User benefits

• Low susceptibility to background noise

• Non contact

Low susceptibility to background noise

Acoustic particle velocity sensors have around 40 dB lower sensitivity to background noise than sound pressure transducers (Forum Acusticum 2005) for three reasons.

First of all, close at the surface of a noise emitting object, the particle velocity signal is dominant as compared to the sound pressure.

Secondly, if background noise is reflecting at the surface of the test object, the corresponding sound pressure doubles and the corresponding acoustic particle velocity goes to zero. These two reasons make measuring the acoustic particle velocity the obvious choice as compared to sound pressure transducers.

Thirdly, sound pressure transducers are omni directional, Microflowns are directional. So microphones pick up three times as much background noise as acoustic particle velocity.

• A particle velocity sensor to measure the sound from a structure in the presence of background noise, H-E. de Bree, W.F. Druyvesteyn, Forum Acousticum 2005

Non contact

Close to a vibrating surface, acoustic particle velocity equals the normal structural velocity.

• The very near field; theory, simulations and measurements, H-E de Bree et al., ICSV11, St. Petersburg 2004

More info

• Background information on end of line control can be found in chapter 17: 'EOL Gears' of the Ebook 
   
• A presentation on the  end of line control can be found at the presentations page