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Interior and exterior sound field control using two dimensional higher-order variable-directivity sources
M A Poletti1, T D Abhayapala, P Samarasinghe
1Industrial Research Ltd, PO Box 31-310, Lower Hutt, Wellington 5040, New Zealand. m.poletti@irl.cri.nz
The Journal of the Acoustical Society of America
|May 8, 2012
Summary
Using higher-order directivity loudspeakers significantly expands the bandwidth for spatial audio reproduction. This approach reduces the number of required loudspeakers, enhancing high-frequency performance and attenuating exterior sound fields.
Area of Science:
- Acoustics
- Audio Engineering
- Signal Processing
Background:
- Spatial sound reproduction aims to create immersive audio experiences.
- High-frequency reproduction demands numerous loudspeakers, posing practical limitations.
Purpose of the Study:
- To investigate the use of higher-order directivity loudspeakers for improved spatial audio.
- To determine the impact on bandwidth, loudspeaker count, and exterior sound fields.
Main Methods:
- Theoretical analysis of loudspeaker directivity orders (Nth order).
- Modeling of sound field reproduction with varying loudspeaker directivity.
- Simulation of interior and exterior sound field characteristics.
Main Results:
- Nth order directivity enables N times bandwidth expansion and exterior field attenuation.
- Removing exterior cancellation constraints allows for approximately 2N times bandwidth increase.
- Higher-order loudspeakers reduce unit count but increase individual unit complexity.
Conclusions:
- Higher-order directivity loudspeakers offer a viable solution for extending spatial audio bandwidth.
- This technology significantly reduces loudspeaker requirements, especially at high frequencies.
- Trade-offs involve increased complexity per loudspeaker unit.
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