Keywords
Citation
(2005), "Ultra-small microphone", Aircraft Engineering and Aerospace Technology, Vol. 77 No. 2. https://doi.org/10.1108/aeat.2005.12777bad.001
Publisher
:Emerald Group Publishing Limited
Copyright © 2005, Emerald Group Publishing Limited
Ultra-small microphone
Ultra-small microphone
Keywords: Electrical equipment, Surface pressure
A new, 2.5 mm low profile, aerodynamically shaped microphone has been introduced by Bruel & Kjaer to simplify the measurement of true surface dynamic pressure (sound pressure) in a number of engineering applications.
Even though the Surface Microphone Type 4949 is only 20 mm in diameter with a height of 2.5 mm including its integrated preamplifier, the acoustical performance (5 Hz-20 kHz) and dynamic range (30-140 dB) of the new pre-polarised device are stated to be the equivalent to those of traditional, much bulkier flush-mounted microphones.
The new all-titanium microphone can be easily integrated into a flexible mounting pad that eliminates the need to drill holes in the test object and minimises the costs of mounting the microphone. Robust and corrosion- resistant, the simple-to-use, accurate surface microphone can withstand harsh environments including wet and oily conditions.
The Type 4949's ultra-low 2.5 mm profile and novel, flexible, disc-formed mounting pad make it ideal for measurement of dynamic pressure (sound pressure) directly on the surface of a aircraft, vehicle or wind power blade or for sound pressure measurements in limited spaces and where flush mounting of conventional microphone/preamplifier combinations would be impossible or may cause undesired side effects. The microphone is also suitable for a wide range of test and measurement applications including: acoustical fatigue testing; aerodynamic noise measurements; noise reduction measurements; transfer path analysis, as well as lift and down-force analysis.
“Despite its total height of only 2.5 mm, the new Surface Microphone Type 4949 has an integrated pre- amplifier and an acoustical performance and dynamic range equivalent to that of a traditional 14- inch flush-mounted microphone. The microphone supports TEDS (Transducer Electronic Data Sheet) and, combined with proven system solutions such as PULSE multi- analysers, brings new dimensions and ease of use to the test engineer,” commented Bruel&Kjaer technical sales engineer, Jeremy Bryceson.
Details available from: Bruel & Kjaer UK Limited. Tel: +44 (0)1438 739000; Fax: +44 (0)1438 739099.