Low frequency directivity control

Student thesis: Master thesis (including HD thesis)

  • Olivier Le Bot
4. term, Acoustics and Audio Technology, Master (Master Programme)
The directivity of loudspeakers is an important factor for the sound field production and perception. If controlling the directivity at high frequencies is easy with waveg- uides, it becomes much harder as long as the frequency decreases and the wavelength becomes bigger than the size of the sound source. An analytical study of tradi- tional setups for controlling the low frequency directivity is made, completed by Finite-Difference Time-Domain simulations. Two solutions to improve the directivity control are proposed. One based on an all pass filter delaying the signal by different amounts at different fre- quencies and another base on the difference of gain of the signal applied on the different subwoofers. The different solutions have been simulated with FDTD methods and tested through measurements of a real setup. Improve- ments have been noted with the proposed solutions.
Publication date1 Jun 2010
Number of pages189
Publishing institutionAalborg Universitet
ID: 32248001