Hybrid passive-active absorption of a microperforated panel in free field conditions

Cobo, Pedro; Cuesta, María

doi:10.1121/1.2739112

Cited by 25 publications

(19 citation statements)

References 12 publications

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“…The low frequency limitation is due to the quarter wavelength condition of the air cavity. Low frequency absorption can be achieved by combining an MPP with an active control system, thus obtaining the so-called hybrid passive-active absorption systems [45][46][47][48].…”

Section: Ef Modelmentioning

confidence: 99%

Multiple-Layer Microperforated Panels as Sound Absorbers in Buildings: A Review

Cobo

Simón

2019

Buildings

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Sound absorbing materials are used in buildings to dissipate sound energy into heat using viscous and thermal processes. Sound absorbers increase the transmission loss of walls, decrease the reverberation time of rooms, and attenuate the noise generated by internal sound sources. Porous absorbers (fibrous, cellular, or granular) are the most used materials in noise control applications because of their high performance-to-cost ratio in the frequency band of interest. However, when cleaning conditions and health reasons are of concern, microperforated panel (MPP) absorbers may be the preferred choice. MPPs, consisting of many minute (sub-millimetric) holes in a panel, are tunable absorbers in a prescribed frequency band, whose main shortcomings are high manufacturing cost and limited absorption frequency band. Currently, the production cost of MPPs can be drastically reduced by means of modern techniques. The absorption frequency band can be considerably enlarged by designing multiple-layer MPPs (ML-MPPs). The aim of this article is to review the high potential of ML-MPPs as a modern, clean, and healthy alternative to porous materials for sound absorption.

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Section: Ef Modelmentioning

confidence: 99%

Multiple-Layer Microperforated Panels as Sound Absorbers in Buildings: A Review

Cobo

Simón

2019

Buildings

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“…An experiment was conducted in an anechoic room using the Filtered-x Least Mean Square (FxLMS) algorithm to determine the sound absorption effect of the passive-active panel. The experiment was conducted at a specific frequency, and the sound absorption was based on a cell located at the back of the panel [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of an Active Reflection Controller That Can Reduce Acoustic Signal Refer to the Angle of Incidence

Pyun

Park

Kim

et al. 2021

Sensors

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Techniques for reducing the reflection of acoustic signals have recently been actively studied. Most methods for reducing acoustic signals were studied using the normal-incidence wave reduction technique. Although the technique of canceling an object from the normal incidence wave is essential, research on reducing acoustic signals according to the angle of incidence is required for practical applications. In this study, we designed, fabricated, and experimented with an active reflection controller that can reduce acoustic signals according to the angle of incidence. The controller consists of a transmitter on one layer, a receiver sensor on two layers, and an acoustic window on three layers. To reduce the reflected signal, a combination of the time delay and phase was applied to the controller to minimize the acoustic signal by up to −23 dB at an angle of 10°. A controller array simulation was performed based on the results of a controlled experiment. In conclusion, our proposed controller can reduce acoustic signals according to the angle of incidence, which makes it suitable for many applications.

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“…The pressure release and impedance matching methods have been proposed for absorption control by minimizing the pressure behind the material or making the equivalent impedance in front of the material equal to that of the medium to eliminate the cause of the wave reflection [6][7][8][9] . The performance of the pressure release method depends on the properties of the passive material, and two sensors are usually needed in the impedance matching method to predict the reflected wave 10 .…”

Section: Introductionmentioning

confidence: 99%