Development of an acoustic filter for parametric loudspeaker using phononic crystals

Ji, Peifeng; Hu, Wenlin; Jiang, Yang

doi:10.1016/j.ultras.2016.01.013

Cited by 21 publications

(6 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As shown in Figure 3, the geometry of the 2D numerical model is corresponding to the experimental setup that is installed in a semi-anechoic chamber (4.0 m (L) × 3.6 m (W) × 2.4 m (H)). The radiation boundary condition which has been successfully employed by other researchers [11,34,35] was applied for the boundaries of semi-anechoic chamber walls, indicating no reflection on these boundaries. For the rest of the walls, the sound hard boundary conditions were applied [11,34].…”

Section: Methodsmentioning

confidence: 99%

“…The radiation boundary condition which has been successfully employed by other researchers [11,34,35] was applied for the boundaries of semi-anechoic chamber walls, indicating no reflection on these boundaries. For the rest of the walls, the sound hard boundary conditions were applied [11,34]. A monopole point source of 1 Pa was used to simulate the sound source, and a domain point probe was used as a virtual sensor to receive the sound signal.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Parametric Optimization of Local Resonant Sonic Crystals Window on Noise Attenuation by Using Taguchi Method and ANOVA Analysis

et al. 2022

View full text Add to dashboard Cite

Local resonant sonic crystals (LRSCs) window as a novel design has recently been proposed to achieve a good balance between noise mitigation, natural ventilation and natural lighting. In an effort to explore the feasibilities of such designs in civil residential buildings, an optimization methodology was proposed to develop a more compact LRSCs window with high noise attenuation performance in the present study. Specifically, the Taguchi method was adopted for the design of experiments on the parameters of interest and their corresponding levels, and SN ratio analysis was then applied for the parametric evaluations on the noise attenuation on specified frequencies in traffic noise (concentrated sound energy frequency range: 630–1000 Hz). Three optimal sets of design parameters on the interested frequencies, namely, 630 Hz, 800 Hz and 1000 Hz were obtained. ANOVA analysis was conducted to quantificationally identify the design parameters with statistical significance and remarkable contribution to the desired performance. Results indicate that the slit size has the most significant influence on the overall noise attenuation performance, followed by cavity width. An optimal set of design parameters to achieve the overall best noise reduction performance in the frequency range of 630–1000 Hz was finally determined by combining the SN ratio and ANOVA analysis. A prototype of the final optimized LRSCs window was then fabricated and tested in a semi-anechoic chamber. Good agreement was found between the experiment and numerical simulation. In comparison to the benchmark case, the final optimized design can achieve a further noise reduction by 2.84 dBA, 3.48 dBA and 5.56 dBA for the frequencies of 630 Hz, 800 Hz and 1000 Hz, respectively. The overall noise reduction for the interested frequency range can be promoted by 3.28 dBA. The results indicate that the proposed optimization methodology is practical and efficient in designing a high-performance LRSCs window or improving similar applications.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Parametric Optimization of Local Resonant Sonic Crystals Window on Noise Attenuation by Using Taguchi Method and ANOVA Analysis

et al. 2022

View full text Add to dashboard Cite

show abstract

“…This discrepancy in the near field is thought to be due to spurious signals induced by the nonlinear response of a microphone diaphragm exposed to finite-amplitude ultrasound and that of connected electronic devices and pseudo sounds caused by the acoustic radiation pressure acting on the diaphragm. 21,22,[24][25][26][27][28][29][30][31] For example, a condenser microphone transforms the variation of gap distance between the vibrating diaphragm and the backplate into an electrical signal. Assuming that the gap variation is small, the output signal of the microphone is proportional to the sound pressure of the incoming sound wave.…”

Section: Introductionmentioning

confidence: 99%

Influence of microphone characteristics on demodulated sound measurement in near field of parametric loudspeaker

Nomura

Sato

2022

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

This study evaluates the accuracy of demodulated sound measurements using a condenser microphone in the near field of a parametric loudspeaker system. Microphones with different sensitivities placed at incidence angles of 0° and 90° were used to measure demodulation frequency components without special acoustic filters. The measured components were compared with theoretical predictions. The results show that the measured sound pressure using microphones placed at 0° was up to several tens of decibels larger than the theoretical predictions and significantly inaccurate in the near field. This was due to the nonlinear response of the microphone, which had high sensitivity at primary sound frequencies, inducing spurious signals. This result suggests that using a microphone with low sensitivity at primary sound frequencies placed at an appropriate angle that reduces sensitivity improves parametric sound measurement accuracy.

show abstract

“…Some methods proposed to avoid the appearance of the spurious signal are based on the use of 37 acoustic filters[14][15][16][17][18][19][20][21] made of a thin plastic film or phononic crystals with a bandgap at the carrier 38 frequency. These filters are mounted in front of the receiving transducer and reduce the amplitude 39 of the primary wave.…”

mentioning

confidence: 99%

Experimental Evaluation of Distortion in Amplitude Modulation Techniques for Parametric Loudspeakers

et al. 2020

View full text Add to dashboard Cite

Parametric loudspeakers can generate a highly directional beam of sound, having applications in targeted audio delivery. Audible sound modulated into an ultrasonic carrier will get self-demodulated along the highly directive beam due to the non-linearity of air. This non-linear demodularization should be compensated to reduce audio distortion, different amplitude modulation techniques have been developed during the last years. However, some studies are only theoretical whereas others do not analyze the audio distortion in depth. Here, we present a detailed experimental evaluation of the frequency response, harmonic distortion and intermodulation distortion for various amplitude modulation techniques applied with different indices of modulation. We used a simple method to measure the audible signal that prevents the saturation of the microphones when the high levels of the ultrasonic carrier are present. This work could be useful for selecting predistortion techniques and indices of modulation for regular parametric arrays.whereand ω are the amplitude and the angular frequency of the carrier, and ( ) is the 4 This dependence implies that the self-demodulated wave ( ) is not linear to ( ) and that it will 5 suffer from high levels of distortion due to the generated harmonics and a strong low-pass 6 equalization. 7 Various preprocessing techniques have been developed to reduce distortion using different 8 modulations of the envelope ( ). Existing experimental measurements [8-10] are mostly based on 9 the total harmonic distortion or at certain representative frequencies, which may not completely 10 capture the non-linear response of the speakers. Here, we present an extensive comparison of the 11 different amplitude modulation techniques under various modulation indices in terms of frequency 12 response, harmonic distortion and intermodulation distortion. This study analyzes the 13 intermodulation distortion and the harmonics distortions of the different amplitude modulation 14 techniques for various modulation indices. Furthermore, the analysis is split by order. To avoid the 15 presence of spurious signal in the measurements, our method previously selects a dynamic 16 microphone with limited frequency response.

show abstract

Development of an acoustic filter for parametric loudspeaker using phononic crystals

Cited by 21 publications

References 26 publications

Parametric Optimization of Local Resonant Sonic Crystals Window on Noise Attenuation by Using Taguchi Method and ANOVA Analysis

Parametric Optimization of Local Resonant Sonic Crystals Window on Noise Attenuation by Using Taguchi Method and ANOVA Analysis

Influence of microphone characteristics on demodulated sound measurement in near field of parametric loudspeaker

Experimental Evaluation of Distortion in Amplitude Modulation Techniques for Parametric Loudspeakers

Contact Info

Product

Resources

About