Broadband monopole emission enhancement using a dual acoustic grating

Lei, Yunzhong; Wu, Jiu Hui; Yang, Shaokun

doi:10.1016/j.physleta.2021.127486

Cited by 2 publications

(1 citation statement)

References 18 publications

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“…[22,23] However, most acoustic metamaterials are designed in a way that makes it challenging for them to have a direct and immediate impact on real-world applications pertaining to the audio industry, with one possible exception being sound absorption. [24] On the one hand, despite the reduction of audio distortion [25] realized by the mitigation of high-frequency acoustical cavity-resonances through the addition of acoustic metamaterial-based absorbers in loudspeaker enclosures, the attempt to incorporate passive acoustic metamaterials [26][27][28][29][30][31][32][33] into the loudspeaker designs has seen very limited radiation enhancement at low frequencies due to the bulky size and the lack of consideration on the metamaterial-transducer coupling. On the other hand, though active acoustic metamaterial may offer a solution to a broadband radiation enhancement, [34] they often involve designs that are complicated to avoid instability and also require more power consumption.…”

Section: Introductionmentioning

confidence: 99%

Metamaterial‐Augmented Head‐Mounted Audio Module

Ji,

Zhao,

Yao

et al. 2023

Adv Materials Technologies

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Recent developments in metamaterial research have shown promising progress in overcoming the fundamental physical limitations of acoustics. While the majority of this research is curiosity‐driven and focused on fundamental physics, there has been a scarcity of acoustic metamaterials research that can have a direct and immediate impact on real‐world applications. In this study, an acoustic metamaterial inside a head‐mounted audio module is incorporate to achieve a 3–7 dB broadband sound pressure level (SPL) improvement in the bass range (50–700 Hz), which is the most challenging frequency range for radiation enhancement. The adoption of the acoustic metamaterial not only enhances voltage sensitivity near the intrinsic metamaterial resonance frequency, but also extends the broadband enhancement to a lower transducer resonance frequency by carefully engineering the metamaterial‐transducer resonant coupling. The improvement of the audio module is demonstrated through fully coupled electrical‐mechanical‐acoustical numerical simulations using finite element analysis, which are validated against comprehensive measurements including electrical impedance analysis, speaker diaphragm displacement analysis, voltage sensitivity and power sensitivity analysis, and spectrogram. This study not only offers a promising path to improve the audio module quality without increasing the size, but also represents an important milestone toward using acoustic metamaterial research to solve audio industry challenges.

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