Acoustic Absorption Performance Research Articles

Experimental Study of the Absorption Coefficient of Acoustic Insulators for Undergraduate University Students

Objective: This study investigates the techniques for measuring the acoustic absorption coefficient that use an impedance tube, to evaluate their use by students of scientific-technical degrees. Theoretical Framework: This topic presents the concept of absorption coefficient and how it is obtained using impedance tubes. Method: The absorption coefficient of an acoustic insulator is measured as a function of frequency, thickness and density, with an experimental system that uses the transfer function method in an impedance tube. Results and Discussion: The results reveal that the absorption coefficient varies with frequency, being lower at low frequencies. An increase in thickness and/or density produces better acoustic absorption performance. The results are compared with others obtained with an experimental system that uses the standing wave method in an impedance tube. The agreement between the two methods is quite good. Research Implications: The advantages and disadvantages of the two methods are discussed, and their use by students of scientific-technical degrees is assessed. It is recommended to use the transfer function method when students work more autonomously, for example, in final degree projects. Originality/Value: This work offers teachers information related to the experimental study of the acoustic absorption coefficient, which allows them to choose the most appropriate method for each student based on their ability to work autonomously and their knowledge.

Study on the influence of void evolution of porous asphalt concrete on acoustic absorption performance under high-temperature loading

This paper investigated the void evolution in porous asphalt concrete (PAC) under high-temperature loading and the resulting decay in acoustic absorption performance. The specimen of PAC-13 with a void content of 20.2 % was designed and loaded with MMLS3 for 0–100,000 cycles at 60℃. Computed tomography techniques were employed to extract the distribution characteristics and structural parameters of voids. Subsequently, the acoustic absorption coefficients were measured at different loading stages. The results indicate that PAC experienced both rapid and gradual reduction phases in air void content under high-temperature loading. After 100,000 cycles of loading, the air void content decreased by 5.44 %, void connectivity decreased by 4.32 %, and the average number of voids in section reduced by 8.30 %. The distribution range of nearly 90 % of void sizes shifted from below 7 mm to below 6 mm after 100,000 cycles. At different loading stages, the void content, average number and average equivalent diameter of connected voids exhibited a positive correlation and similar trends with the absorption capacity of PAC for small vehicle noise. This study provides novel insights and perspectives into the acoustic performance degradation of PAC due to void evolution under high-temperature loading.

Rectangular extended neck Helmholtz resonant acoustic structure for low frequency broadband sound absorption

The Helmholtz resonant structure with rectangular extended neck is designed to solve low-frequency broadband sound absorption problem in this work. Theoretical and finite element absorption models are established and be used for low-frequency acoustic design. What makes it interesting is that all parameters of the rectangular extended neck Helmholtz resonator structure can be adjusted to shift the working frequency. Based on the regularity of the structural parameters, four coupling structures with different neck depths, neck opening areas, cavity cross-sectional areas, and cavity depths are designed respectively, each of which exhibited multiple sound absorption coefficient peaks to enhance the low-frequency absorption capacity of the structure. To further analyze the effectiveness of coupling structure, the broadband acoustic absorption mechanism of the coupled structure is analyzed based on particle vibration velocity distribution. It is found that cells with different acoustic impedance contributed differently to the sound absorption, and cells with longer necks provided better noise reduction for low-frequency. The experiment is verified in the impedance tube, result shows that the coupling structure with 9 cells and a cavity depth of only 4 cm achieved an average sound absorption coefficient of above 0.8 at 210–340 Hz, which verified the accuracy of the theoretical model. Overall, the Helmholtz resonant cavity acoustic structure with rectangular extension neck designed in this work has a simple structure with low-frequency broadband acoustic absorption performance. This provides a new approach for designing low-frequency broadband acoustic structure.

Design of an adjustable sound-absorbing structure with low frequency advantages

The thickness of microperforated panel absorbers with low-frequency sound absorption ability is often large and the absorption bandwidth is limited. To address this issue, a adjustable microperforated panel structure with low-frequency advantage (ASWLF) was designed. Compared to conventional structures, the introduction of inclined chambers allows the structure to absorb lower-frequency noise at the same thickness, enhancing spatial utilization efficiency. The addition of a rotating structure design broadens the frequency range over which the structure can operate effectively. The addition of a rotating structure design broadens the frequency range of the structure's action. The acoustic absorption coefficient of the model can be calculated using acoustic-electric analogy, which is used to predict the acoustic absorption coefficient of the ASWLF structure. The experimental results show that, with the same acoustic absorption performance, the thickness of the structure is reduced by 36.7%. The multi-stage combination allows the structure to achieve better acoustic absorption performance in a wider frequency band. By introducing the PSO optimization algorithm, the optimized ASWLF structure further improves the acoustic absorption frequency band by 32.9%. This study provides an effective method for solving noise environments under different conditions in industrial practical applications.

Study on sound absorption valley and acoustic absorption performance of small-pore aluminum foam composited with 304 stainless steel fibers

Open-cell aluminum foam exhibits a sound absorption valley (SAV) in the 2500–4000 Hz frequency range, reducing its acoustic absorption in the range of 1000–6300 Hz. A small-pore aluminum foam composited with 304 stainless steel fibers (SP-SS304F aluminum foam) with a porosity of 82 % was fabricated via infiltration casting, and its pore structure, acoustic absorption performance, and mechanism were investigated. The pore structure of SP-SS304F aluminum foam consisted of 223–676 μm main pores, 125–373 μm cell wall pores, and 30–60 μm 304 stainless steel fibers. The fibers existed completely embedded in the cell walls, partially or completely embedded in the cell cavities. As the pore diameter decreases, the SAV value increases and then decreases. With increasing fiber content, the SAV value showed a similar trend. The increased SAV value benefits the enhancement of the average sound absorption coefficient (SAC). The SP-SS304F foam aluminum reaches an optimal SAC value of 0.899. Its static resistivity value is 24,345 Pa.s/m2. Finite element simulations reveal the reasons for the improved acoustic absorption performance of SP-SS304F aluminum foam: First, the small-diameter and pore-embedded fibers improve the acoustic impedance matching, reducing sound reflections at the SAV frequency. Second, the reduced pore diameters and partially or completely pore-embedded fibers increase the pore surface areas, intensifying the acoustic absorption by pore structure.

Acoustic properties of natural fiber reinforced composite micro-perforated panel designed using 3D printing

The present study investigated the acoustic performance of biodegradable MPP absorbers made of natural fiber-reinforced composites (NFRC) using 3D printing. The novelty of this current research lies in the recent development of a methodology that aids industry professionals in optimizing the production of MPP (Micro Perforated Panel) at a competitive cost. This is achieved by addressing and eliminating issues commonly faced in traditional manufacturing processes, such as manual preparation and pressing. The FDM technique was used to fabricate test samples utilizing the PLA/corkwood composite. Using an impedance tube device with two microphones, the acoustic absorption coefficients of MPPs with different perforation diameters, thicknesses, and perforation rates were measured. Maa's analytical model was used to predict the acoustic absorption performance. Moreover, considering the average sound absorption and total cost of fabricating the samples, RSM-CCD was employed to optimize these samples. In the end, the parallel arrangement of MPP double layer and the combination of MPP with kenaf porous material were tested to improve the sound absorption performance. The results showed that the average sound absorption coefficient of the NFRC-MPP sound absorber is 25% more than that of conventional MPP sound absorbers.

A novel broadband underwater sound absorption metastructure with multi-oscillators

Underwater absorptive metamaterials are rapidly developed duo local resonance mechanisms, but they still suffer from the disadvantages of poor hydrostatic resistance. The poor acoustic absorption performance at high hydrostatic pressure mainly attributes to the decreased damping coefficient and increased modulus of substrate at high hydrostatic pressure. Acoustic metastructures with helical oscillators are proposed and optimized with simulating annealing algorithm, where the helical oscillators are beneficial for easing the stress in the polymer substrate and resulting in good acoustic absorption abilities. Four acoustic absorptive metastructures without any oscillators (pure polymer substrate), with cylindrical oscillators, with helical oscillators, with both cylindrical and helical oscillators are proposed and experimentally verified in this study. All three metastructures with oscillators demonstrate excellent acoustic absorption coefficient with the absence of the hydrostatic pressure, while the metastructures with helical oscillators exhibit better hydrostatic pressure resistance compared with the metastructures with cylindrical oscillators. Besides, the coupling of helical oscillators and helical oscillators enhanced the acoustic performance furtherly. It is revealed that the acoustic metamaterials with a combination of cylindrical oscillator and helical oscillator exhibit superior performance under hydrostatic pressure up to 3 MPa in the frequency range of 0.5kHz∼10 kHz compared with the others, demonstrating a new avenue for underwater acoustic metamaterials application.

Effects of Freeze-Drying Processes on the Acoustic Absorption Performance of Sustainable Cellulose Nanocrystal Aerogels.

Cellulose aerogels have great prospects for noise reduction applications due to their sustainable value and superior 3D interconnected porous structures. The drying principle is a crucial factor in the preparation process for developing high-performance aerogels, particularly with respect to achieving high acoustic absorption properties. In this study, multifunctional cellulose nanocrystal (CNC) aerogels were conveniently prepared using two distinct freeze-drying principles: refrigerator conventional freezing (RCF) and liquid nitrogen unidirectional freezing (LnUF). The results indicate that the rapid RCF process resulted in a denser CNC aerogel structure with disordered larger pores, causing a stronger compressive performance (Young's modulus of 40 kPa). On the contrary, the LnUF process constructed ordered structures of CNC aerogels with a lower bulk density (0.03 g/cm3) and smaller apertures, resulting in better thermal stability, higher diffuse reflection across visible light, and especially increased acoustic absorption performance at low-mid frequencies (600-3000 Hz). Moreover, the dissipation mechanism of sound energy in the fabricated CNC aerogels is predicted by a designed porous media model. This work not only paves the way for optimizing the performance of aerogels through structure control, but also provides a new perspective for developing sustainable and efficient acoustic absorptive materials for a wide range of applications.

Acoustic properties of underwater acoustic metamaterials based on multi-physical field coupling model

In this paper, according to the internal structure of underwater acoustic metamaterial, a multi-physical field coupling model of underwater acoustic metamaterial is established by using finite element analysis. Based on the model, the influence of typical underwater acoustic metamaterial structure and material parameters on sound absorption performance is studied. The results show that increasing the height or radius of the local resonance mass unit in the metamaterial is beneficial to improve the low frequency sound absorption performance. With the increase of the distance between mass elements and the thickness of elastic material, the acoustic absorption performance increases first and then decreases. Increasing the elastic modulus of elastic material of the local resonance unit or matrix will lead to the decrease of low frequency sound absorption performance of the material and the improvement of high frequency sound absorption performance. Increasing the loss factor of elastic material of the local resonance unit or matrix material can broaden the sound absorption band. These rules can provide guidance for the design of underwater acoustic metamaterials.

Acoustic properties of natural fiber reinforced composite micro-perforated panel (NFRC-MPP) made from cork fiber and polylactic acid (PLA) using 3D printing

The present study investigated the acoustic performance of biodegradable MPP absorbers made of natural fiber-reinforced composites (NFRC) using 3D printing. The novelty of this current research lies in the recent development of a methodology that aids industry professionals in optimizing the production of MPP (Micro-Perforated Panel) at a competitive cost. This is achieved by addressing and eliminating various issues commonly faced in traditional manufacturing processes, such as manual preparation and pressing. The FDM technique was used to fabricate test samples utilizing the PLA/corkwood composite. Using an impedance tube device with two microphones, the acoustic absorption coefficients of MPPs with different perforation diameters, thicknesses, and perforation rates were measured. Maa's analytical model was used to predict the acoustic absorption performance. Moreover, considering the average sound absorption and total cost of fabricating the samples, RSM-CCD was employed to optimize these samples. In the end, the parallel arrangement of MPP double layer and the combination of MPP with kenaf porous material were tested in order to improve the sound absorption performance. The results showed that the average sound absorption coefficient of the NFRC-MPP sound absorber is 25 % more than that of conventional MPP sound absorbers. The sample with a perforation diameter of 0.70 mm, a panel thickness of 0.90 mm, and an 8 mm distance between the perforations was selected as the optimal sound absorber. The measurement and model data for NFRC-MPP panels do not correspond well. The parallel arrangement of two layers of MPP and the addition of an optimized kenaf layer behind the MPP significantly improved the sound absorption performance in the intended frequency range. The findings of this study, coupled with data available in the literature for other types of biocomposite Micro-Perforated Panel (MPP), strongly indicate that Cork fiber-based MPP exhibits substantial promise for application, either independently or in conjunction with Kenaf materials, as a material for acoustic conditioning. Implementing smart manufacturing techniques for acoustic panels not only enhances engineering noise control efforts but also amplifies the overall effectiveness of Hearing Conservation Programs.

Sustainable versatile chitin aerogels: facile synthesis, structural control and high-efficiency acoustic absorption.

Bio-based materials with excellent acoustic absorption properties are in great demand in architecture, interior, and human settlement applications for efficient noise control. In this study, crayfish shells, a form of kitchen waste, are utilized as the primary material to produce ultralight and multifunctional chitin aerogels, which effectively eliminate noise. Different replacement solvents and freezing rates were employed to regulate the porous structures of chitin aerogels, and their resulting acoustic absorption performance was investigated. Results demonstrate that employing deionized water as the replacement solvent and utilizing a common-freeze mode (frozen via refrigerator at -26 °C) can produce chitin aerogels with larger porosity (96.26%) and apertures, as well as thicker pore walls. This results in superior broadband acoustic absorption performance (with a maximum absorption coefficient reaching 0.99) and higher Young's modulus (28 kPa). Conversely, chitin aerogels solvent-exchanged with tert-butyl alcohol or subjected to quick-freeze mode (frozen via liquid nitrogen) exhibit smaller porosity (92.32% and 94.84%) and apertures, thereby possessing stronger diffuse reflection of visible light (average reflectance of 94.30% and 88.18%), and enhanced low-frequency (500 to 1600 Hz) acoustic absorption properties. Additionally, the acoustic absorption mechanism of fabricated chitin aerogels was predicted using a simple three-parameter analysis Johnson-Champoux-Allard-Lafarge (JCAL) model. This study presents a novel approach to developing multifunctional biomass materials with excellent acoustic absorption properties, which could have a wide range of potential applications.

A tunable slit-plate absorber with multiparameter cooperative control

Tunable acoustic metamaterials have a more flexible operating spectrum while still controlling acoustic waves via subwavelength thickness, but their operating range and acoustic absorption performance are limited by a single-parameter tuning mechanism. In this study, we first propose a slit-plate absorber with reconstructed porosity, which has a dynamic continuous tuning capability and is easier to achieve low-frequency resonance. Then, in order to improve its acoustic absorption performance, we study the tuning laws of numerous structural factors as well as their cooperative interaction. Local parameter changes to achieve impedance compensation and isotropic control to enhance frequency shift are presented to greatly improve the tunable range and sound absorption level. A tunable absorber with multi-parameter cooperative control is constructed using this method. The results reveal that continuous tuning of 210–920 Hz is possible at a total thickness of 25 mm, and the sound absorption coefficient in the tuning range is more than 0.8, and the thickness of the structure at 210 Hz is 1/65 of the absorption wavelength. Our work demonstrates a new method for improving the performance of adjustable acoustic metamaterials and promotes the use of acoustic metamaterials in low frequency changing noise environments.

Relation between Acoustic Absorption Performance and Flow Field around Perforated Plate with Cross Flow

The present paper focuses on the relationship between the acoustic absorption performance and the flow field around a perforated plate with cross-flow. The normal incidence absorption coefficient was calculated from the measured transfer function using transfer function methods. As the flow velocity passing through the orifices increased, the peak level of the acoustic absorption coefficient increased in some cases. We observed the flow field around a perforated plate by flow visualization using a laser. The vortices were clearly formed downstream of the orifices due to the incident sound of pure tone. We discussed the relationship between the vortex and the acoustic absorption performance of perforated plate with a cross flow.

Sound absorption performance of micro-perforated plate sandwich structure based on triply periodic minimal surface

The sandwich structure based on Triply periodic minimal surface (TPMS) is a lightweight and high-strength multifunctional composite material that combines the versatility of heat exchange, impact resistance, and energy absorption, and has been widely used in various fields such as aviation and aerospace. However, its sound absorption performance has not meant fully studied. In this paper, a Micro-perforated plate Diamond sandwich structure (MPP-DSS) was designed based on TPMS method, which was composed of aluminum alloy solid panel, aluminum alloy macroscopically ordered porous Diamond structure and aluminum alloy micro-perforated plate. The acoustic absorption performance in low and medium frequency band was studied by impedance tube method. The results show that MPP-DSS has higher absorption coefficient and bandwidth than traditional perforated plate structure with the same structural parameters. Increasing the thickness of micro-perforated plate can improve the sound absorption capacity of MPP-DSS in the low frequency range, but the width of the sound absorption band will be narrowed accordingly. Different from the resonant sound absorption mechanism of the traditional perforated plate structure, the sound absorption mechanism of MPP-DSS is the combined effect of resonant sound absorption and friction loss sound absorption. This study broadens the versatility of the TPMS structure and can serve as a reference for the design of integrated load-bearing and sound-absorbing structures.

Effect of Crumb Rubber Particles on Antisliding and Noise-Reduction Performance of Asphalt Pavement

Traffic noise has gradually become the primary source of noise in urban areas. The risk of health issues such as cardiovascular diseases and sleep disturbances associated with noise exposure are receiving widespread attention. The skid resistance of asphalt pavements is important for safe driving. However, its antisliding performance deteriorates owing to automobile driving, and the antisliding index cannot satisfy requirements of long-term safe driving. Crumb rubber-modified asphalt (CRMA) has been widely used owing to its characteristics, such as excellent noise reduction, antisliding performance, and durability. This study aims to investigate the effect of crumb rubber (CR) particle content (0%, 2%, 3%, and 4% by weight of fine aggregates in asphalt mixture) on the antisliding and noise reduction characteristics of asphalt pavements. The functional performances of three different types of asphalt mixtures were tested to obtain the best gradation. Then, an accelerated wear tester was used to analyze the deterioration of the antisliding performance under different cumulative load times. A British pendulum number (BPN) tester and 3D laser technology were used to measure friction properties and texture depths of asphalt mixtures with varying CR particle contents after wheel-load repetitions. The tire-drop and standing wave tube methods were employed to evaluate the noise-reduction characteristics and acoustic absorption performance of asphalt mixtures with varying CR particle contents. Finally, the optimal CR particle content was determined using grey-target decision-making based on the entropy weight method. The results indicate that adding rubber particles to asphalt mixtures slows down the attenuation rate of BPN and texture depth, which shows a clear enhancement of the antisliding performance. The addition of rubber particles to asphalt mixtures improves the noise-reduction performance in tire-pavement systems by increasing damping properties and the sound absorption coefficient. The asphalt mixture with 3% rubber particles exhibited the optimal performance.

Porous liner coated inlet duct: a novel approach to attenuate automotive turbocharger inlet flow-induced sound propagation

Automotive turbochargers generate high-frequency noise, especially at their inlet air duct, which has become a long-standing problem for both passengers and pedestrians and hence is required to be mitigated by provisions such as the use of absorptive materials and novel inlet duct designs. This paper proposes utilizing a thin porous material coating liner on the inlet duct of the turbocharger compressor in order to absorb the incident excitation and hence, broadband reduction of the flow-induced sound wave propagation. To this end, first, a sound-absorbing inlet duct model is designed based on efficient structural parameters. Then, three different types of absorptive materials are used as coating liners to analyze the impact of varying material properties on the acoustic absorption performance of the system. Meanwhile, a sensitivity analysis is carried out to evaluate the influence of coating layer thickness on the system’s flow-induced sound insulation performance. The research involves applying a finite element approach to conducting acoustic pressure and poroacoustics studies over the desired frequency range of human hearing (1–20 kHz). In this regard, sound transmission loss (TL) and sound pressure level (SPL) are investigated for the models with and without liners. The results indicate that sound-absorbing materials can be employed to significantly diminish flow-induced sound levels in the turbocharger inlet duct. According to the results, absorptive liners would considerably increase the maximum TL and lessen the sharp drop in TL that appeared in the model without liners at around 4321 Hz. In addition, the average TL has increased due to the replacement of valleys with peaks. The sensitivity analyses demonstrated that denser absorptive materials and larger liner thicknesses are associated with higher TL levels and better sound attenuation response. By adding 15 mm of rock wool liner to the designed inlet duct, the average TL and root mean square of TL were increased up to and respectively. The proposed design procedure of this study unlocks a fundamental approach that can be practically applied to many promising fields, such as aerospace and automotive engineering.

Development of multiscale Fe/SiC–C fibrous composites for broadband electromagnetic and acoustic waves absorption

The explosive development of wireless communication devices and modern electronic machines raises concerns about potential human health threats from their extensive emission of electromagnetic waves (EMW) and acoustic noise. However, the insufficient lossy medium, monotonous structure, and large fiber diameters limit the broadband EMW and noise absorption of traditionally used fibrous materials. Here, we developed electro-spun Fe-doped and SiC nanoparticle-loaded carbon fibrous membranes (Fe/SiC–C) and their multiscale composites for effective broadband EMW and acoustic waves absorption performance. The Fe/SiC–C fibrous membranes show an excellent EMW absorption bandwidth (EAB) of 6.98 GHz at a thickness of 2.45 mm. Integrating a macroscale double-layer periodic cuboid design, we fabricated Fe/SiC–C fibrous metastructure composites that exhibit broadband EMW absorption with EAB of 15.2 GHz ranging from 2.8 GHz to 18 GHz at a total thickness of 8.45 mm. Additionally, using a simple roll-up method, we assembled the Fe/SiC–C fibrous membranes into a bulk sound absorber with a superior noise reduction coefficient (NRC) of 0.57 at a thickness of 30 mm. The multiscale development of carbon-based fibrous composites enables their potential application to electromagnetic and acoustic waves absorption.

Experimental study on durability and acoustic absorption performance of biomass geopolymer-based insulation materials

The biomass-based insulation materials have been identified as low-embodied energy materials that reduce energy use and CO2 emissions, particularly in construction. However, as satisfactory insulation material, it must also ensure durability under changing climate conditions. This work investigated the effect of freeze–thaw, wet-dry and cool-heat cycles on the appearance, compressive strength and thermal conductivity of biomass (wheat straw, rice husk and sawdust) geopolymer-based insulation materials. The results showed that, these samples had a good skeleton structure. By contrast, the wheat straw geopolymer-based (WG) samples showed better durability with compressive strength losses of 19.4 %, 1.3 % and 2.6 % in the three modes, respectively. In addition, the WG samples had high sound absorption performance (0.71 at 1028 Hz). This study provides a more systematic analysis of the durability and sound absorption of biomass geopolymer-based insulation materials, which are crucial for their practical application.

Sound Absorption Improvement in Porous Ferroelectret Polyethylene with Effective Piezoelectric Mechanism.

Airborne sound absorption in porous materials involves complex mechanisms of converting mechanical acoustic energy into heat. In this work, the effective piezoelectric properties of polyethylene ferroelectret foams on sound absorption were investigated by comparable samples with and without the piezoelectric response. Corona poling and thermal annealing treatments were applied to the samples in order to enable and remove the piezoelectric property, respectively, while the microstructure and the mechanical properties remained substantially unchanged. The effective piezoelectric properties and airborne sound absorption coefficients of the polyethylene foam samples before and after material treatments were measured and analyzed. Our experimental results and theoretical analysis showed that the open-cell ferroelectret polymer foam with an effective piezoelectric property provides an additional electromechanical energy conversion mechanism to enhance the airborne acoustic absorption performance.

Improving the sound absorption of a highly deformable nanocomposite foam based on ethylene-propylene-diene-monomer (EPDM) infused with multi-walled carbon nanotubes (MWCNTs) to absorb low-frequency waves

In this study, an elastomeric nanocomposite foam was fabricated on the basis of ethylene-propylene-diene-monomer (EPDM) rubber filled with multi-walled carbon nanotubes (MWCNTs) to absorb low-frequency acoustic waves. The effects of adding MWCNTs on the cellular structure, viscoelastic behavior, and sound absorption characteristics were studied. Samples containing slight loadings of MWCNTs with increased damping factor and decreased pore sizes showed high viscose motions with superior sound absorption characteristic. The results revealed that the nanocomposite foam sample with only 0.1 phr (parts per hundred rubber) MWCNTs offered the best sound absorption coefficient with a sharp peak (0.98) within the frequency range of 500–1000 Hz. This can be justified by the dissipation of acoustic energy through vibration and deformation of the flexible cell walls due to the highly elastic matrix, high porosity and airflow resistivity of the fine partially reticulated cellular structure. With further MWCNTs loadings beyond the optimum level, the cell size was reduced dramatically, leading to reduction in porosity and excessive increase in air flow resistivity. These factors resulted in poor sound absorption feature. Moreover, the sound insulation performance of the nanocomposite foams was characterized, and it revealed the improving effect of MWCNTs, especially in high loading, by yielding a sound reduction index equal to 27–33 dB. According to the obtained results, the potential role of MWCNTs in the improvement of the acoustic absorption and sound insulation performance of EPDM foam can be inferred. Thus, a lightweight sound absorber with high resistance to harsh environmental conditions and excellent low-frequency sound absorption can be achieved by the infusion of nanoparticles.