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A nonreciprocal and tunable active acoustic scatterera)
Anis Maddi1, Gaelle Poignand1, Vassos Achilleos1
1Laboratoire d'Acoustique de l'Université du Mans (LAUM), UMR 6613, Institut d'Acoustique-Graduate School (IA-GS), CNRS, Le Mans Université, France.
The Journal of the Acoustical Society of America
|May 19, 2025
Summary
This study demonstrates how asymmetric electroacoustic feedback in loudspeakers enables novel sound wave manipulation. The system achieves unique effects like one-way transmission and directional amplification in the subwavelength regime.
Area of Science:
- Acoustics
- Wave phenomena
- Metamaterials
Background:
- Passive loudspeakers typically act as reciprocal scatterers for sound waves.
- Breaking acoustic reciprocity is key to controlling sound propagation.
- Asymmetric electroacoustic feedback offers a method to manipulate sound waves.
Purpose of the Study:
- To investigate the scattering properties of actively controlled loudspeakers with asymmetric feedback.
- To explore exotic acoustic effects achievable with this system.
- To demonstrate the versatility of asymmetrically active scatterers.
Main Methods:
- Utilizing a pair of actively controlled loudspeakers connected by a duct.
- Implementing asymmetric electroacoustic feedback using microphones.
- Conducting theoretical analysis and experimental validation.
- Operating within the subwavelength regime.
Main Results:
- Demonstrated an asymmetric reflectionless configuration enabling one-way transmission or absorption.
- Achieved a directional amplifier with significant isolation (42 dB).
- Observed a quasi-coherent perfect absorption (CPA)-lasing configuration.
Conclusions:
- The proposed system offers versatile control over sound waves.
- Asymmetric active scatterers provide a powerful platform for manipulating acoustic phenomena.
- The achieved effects are realized in a compact, subwavelength setup.
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