Measuring different acoustical properties have been the key in reducing noise and
improving the sound quality from various sources. In this report, a broadband (200 Hz –
6.5 kHz) three-dimensional seven-microphone intensity probe system is developed to
measure the sound intensity, and total energy density in different acoustical
environments. Limitations of most commercial intensity probes in measuring the three-dimensional
intensity for a broadband sound field was the main motivation in developing
this probe. The finite-difference error and the phase mismatch error which are the two
main errors associated with the intensity measurements are addressed in this report.
As for the physical design, seven microphones were arranged in a two-concentric
arrays with one microphone located at the center of the probe. The outer array is for low-frequencies
(200 Hz – 1.0 kHz), and the inner one is for high-frequencies (1.0 kHz – 6.5
kHz). The screw adjustable center microphone is used for the microphone calibration,
and as the reference microphone of the probe. The simultaneous calibrations of all the microphones in the probe were done in the anechoic room. Theories for the intensity and
the energy densities calculations for the probe were derived from the existing four-microphone
probe configuration. Reflection and diffraction effects on the intensity
measurements due to the presence of the microphones, and the supporting structures were
also investigated in this report. Directivity patterns of the calculated intensity showed the
omnidirectional nature of the probe.
The intensity, and total energy density were calculated and compared with the
ideal values in the anechoic room environment. Characterization of sound fields in a
reverberant enclosed space, and sound source identification are some applications that
were investigated using this probe. Results of different measurements showed
effectiveness of the probe as a tool to measure key acoustical properties in many practical environments. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/6563 |
| Date | 19 October 2009 |
| Creators | Miah, Khalid Hossian |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Format | electronic |
| Rights | Copyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. |
Page generated in 0.0018 seconds