PID-like active impedance control for electroacoustic resonators to design tunable single-degree-of-freedom sound absorbers

Guo, Xinxin; Volery, Maxime; Lissek, Hervé

doi:10.1016/j.jsv.2022.116784

Cited by 10 publications

(6 citation statements)

References 19 publications

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“…Such subwavelength acoustic control can theoretically be extended down to even lower frequencies, but limitations of the experimental setup prevent us from measuring lower frequencies with a sufficient signal-to-noise ratio. The highest considered frequency is limited due to several assumptions in the analytical model that do not hold anymore at high frequencies (in particular, the collocation of heat and force sources), and delays in the control system that lead to an unavoidable drift in the achieved impedance 25 , as well as the approximation of the control transfer function by rational polynomials of finite order. As a reference case, we also plot the absorption curve of a porous material of similar thickness backed by a hard wall.…”

Section: Resultsmentioning

confidence: 99%

Ultrabroadband sound control with deep-subwavelength plasmacoustic metalayers

2023

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Controlling audible sound requires inherently broadband and subwavelength acoustic solutions, which are to date, crucially missing. This includes current noise absorption methods, such as porous materials or acoustic resonators, which are typically inefficient below 1 kHz, or fundamentally narrowband. Here, we solve this vexing issue by introducing the concept of plasmacoustic metalayers. We demonstrate that the dynamics of small layers of air plasma can be controlled to interact with sound in an ultrabroadband way and over deep-subwavelength distances. Exploiting the unique physics of plasmacoustic metalayers, we experimentally demonstrate perfect sound absorption and tunable acoustic reflection over two frequency decades, from several Hz to the kHz range, with transparent plasma layers of thicknesses down to λ/1000. Such bandwidth and compactness are required in a variety of applications, including noise control, audio-engineering, room acoustics, imaging and metamaterial design.

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Section: Resultsmentioning

confidence: 99%

Ultrabroadband sound control with deep-subwavelength plasmacoustic metalayers

2023

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“…To better understand how the controls are implemented, we first describe the linear dynamics of the loudspeaker membrane in the time domain as follows: where v ( t ) and ξ ( t ) denote the axial inward velocity and displacement of the diaphragm, respectively. The resonance properties exhibited are related to the mechanical and electromagnetic parameters of the resonator actuated, namely the effective surface area and the moving mass of the diaphragm S d and M ms , the force factor of the moving coil B ℓ , the resistance factored into the global losses R ms , and the overall equivalent compliance C mc where both the elastic suspension of the loudspeaker and the compressibility of the fluid inside the enclosure are accounted for (details can be found in Rivet 38 or Guo et al 43 ).…”

Section: Methodsmentioning

confidence: 99%

Observation of non-reciprocal harmonic conversion in real sounds

2023

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Reciprocity guarantees that in most media, sound transmission is symmetric between two points of space when the location of the source and receiver are interchanged. This fundamental law can be broken in non-linear media, often at the cost of detrimental input power levels, large insertion losses, and ideally prepared single-frequency input signals. Thus, previous observations of non-reciprocal sound transmission have focused on pure tones, and cannot handle real sounds composed of various harmonics of a low-frequency fundamental note, as generated for example by musical instruments. Here, we extend the reach of non-reciprocal acoustics by achieving large, tunable, and timbre-preserved non-reciprocal transmission of sound notes composed of several harmonics, originating from musical instruments. This is achieved in a non-linear, actively reconfigurable, and non-Hermitian isolator that can handle arbitrarily low input power at any audible frequency, while providing isolation levels up to 30dB and a tunable level of non-reciprocal gain. Our findings may find applications in sound isolation, noise control, non-reciprocal and non-Hermitian metamaterials, and analog audio processing.

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“…Misestimations of these parameters can result in the synthesis of multiple-degreesof-freedom impedances, which is perhaps made evident by an increased evanescent component Im(q ) of the wave around the local resonance in the experimental dispersion. More-accurate impedance-synthesis control schemes may be worth investigating [40,41] to mitigate these effects. That being said, this high-energy dissipation at the resonance has little, if any, effect on the Bragg gap, which is the focus of this work.…”

Section: B Experimental Demonstrationmentioning

confidence: 99%

Active Acoustic Su-Schrieffer-Heeger-Like Metamaterial

Padlewski,

Volery,

Fleury

et al. 2023

Phys. Rev. Applied

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An acoustic dimer composed of two electronically controlled electroacoustic resonators is presented with the view of exploring one-dimensional topological phenomena. Active control allows real-time manipulation of the metamaterial's properties, including its mechanical mass, resistance, compliance, and internal coupling. The latter enables active tuning of the topological phase transition in the effective acoustic Su-Schrieffer-Heeger system. An analytical model of the unit cell as well as the electronic control scheme is provided. Band structures derived from the analytical model, the finite-element simulation, and the experimental data consistently demonstrate the realization of a tunable one-dimensional topological insulator.

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PID-like active impedance control for electroacoustic resonators to design tunable single-degree-of-freedom sound absorbers

Cited by 10 publications

References 19 publications

Ultrabroadband sound control with deep-subwavelength plasmacoustic metalayers

Ultrabroadband sound control with deep-subwavelength plasmacoustic metalayers

Observation of non-reciprocal harmonic conversion in real sounds

Active Acoustic Su-Schrieffer-Heeger-Like Metamaterial

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