STANDING WAVES IN A RECTANGULAR SOUND BOX RECORDED BY TV HOLOGRAPHY
✍ Scribed by A. RUNNEMALM
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 976 KB
- Volume
- 224
- Category
- Article
- ISSN
- 0022-460X
No coin nor oath required. For personal study only.
✦ Synopsis
A simple but informative whole-"eld method to visualize standing waves in air enclosures is presented. The integrated sound pressure "eld distribution of standing-wave patterns inside a rectangular, air-"lled transparent box is measured using ordinary TV holography (also called ESPI or DSPI). The phase distribution of the sound pressure is measured by using the more complicated, phase-modulated TV holography technique. Standing waves in the box are excited by a loudspeaker. The structural vibration amplitude distribution of the walls of the same box (operational de#ection shapes, ODSs) are measured at the same frequencies as the standing waves with the same optical technique. The pressure maps obtained and the corresponding structural ODSs are of great pedagogical value and can be used to verify numerical models, etc. Standing-wave patterns in non-rectangular enclosures, as the sound box of a guitar, illustrates the usefulness of the method.