scholarly journals Validation of low frequency noise attenuation using locally resonant patches

2016 ◽  
Vol 139 (6) ◽  
pp. 3267-3276 ◽  
Author(s):  
Maaz Farooqui ◽  
Tamer Elnady ◽  
Wael Akl
Keyword(s):  
Low Frequency ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Low Frequency Noise

Reply by the authors to the Discussion by B. Biswas

Geophysics ◽  
1989 ◽  
Vol 54 (3) ◽  
pp. 406-407
Author(s):  
T. L. Davis ◽  
G. M. Jackson
Keyword(s):  
Noise Reduction ◽  
Low Frequency ◽  
Phase Response ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Low Frequency Noise ◽  
Seismic Wavelet

28 Hz geophones without a low‐cut filter provided a very similar amplitude (and phase) response to the 10 Hz geophones combined with a 25 Hz low‐cut filter. Combining 28 Hz geophones with a 15 or 20 Hz low‐cut filter would produce a record intermediate between Figure 4b and c. There is, however, a tradeoff between low‐frequency noise attenuation and the bandwidth of the seismic wavelet. Before stacking and deconvolution, the more severe low‐cut filtering produces dramatic noise reduction (Figure 4). After deconvolution and stacking, this improvement is much less dramatic. It was decided not to attenuate frequencies in the 10 to 25 Hz range too severely as this could decrease the signal bandwidth and provide a more “ringy,” if marginally cleaner, section.

Low-frequency noise attenuation in seismic and microseismic data using mathematical morphological filtering

2017 ◽  
Vol 211 (3) ◽  
pp. 1296-1318 ◽  
Author(s):  
Weilin Huang ◽  
Runqiu Wang ◽  
Shaohuan Zu ◽  
Yangkang Chen
Keyword(s):  
Low Frequency ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Low Frequency Noise ◽  
Microseismic Data ◽  
Morphological Filtering

Modular Design for Acoustic Metamaterials: Low‐Frequency Noise Attenuation

2021 ◽  
pp. 2105712
Author(s):  
Lingling Wu ◽  
Zirui Zhai ◽  
Xinguang Zhao ◽  
Xiaoyong Tian ◽  
Dichen Li ◽  
...  
Keyword(s):  
Modular Design ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Acoustic Metamaterials ◽  
Low Frequency Noise

Broadband low-frequency noise reduction using Helmholtz resonator-based metamaterial

2021 ◽  
Vol 69 (4) ◽  
pp. 351-363
Author(s):  
Jhalu Gorain ◽  
Chandramouli Padmanabhan
Keyword(s):  
Transmission Loss ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Broadband Noise ◽  
Unit Cell ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
Pu Foam

Achieving broadband noise attenuation at low frequencies is still a significant challenge. Helmholtz resonators offer good low-frequency noise attenuation but are effective only over a narrow band; the cavity volume required at these frequencies is also larger. This article proposes a new broadband acoustic metamaterial (AMM) absorber, which uses polyurethane (PU) foam embedded with small-size resonators tuned to different frequencies. The AMM design is achieved in three phases: (1) develop a transfer-matrix-based one-dimensionalmodel for a resonator with intruded neck; (2) use this model to develop a novel band broadeningmethod, to select appropriate resonators tuned to different frequencies; and (3) construct a unit cell metamaterial embedded with an array of resonators into PU foam. A small-size resonator tuned to 415 Hz is modified, by varying the intrusion lengths of the neck, to achieve natural frequencies ranging from 210 to 415 Hz. Using the band broadening methodology, 1 unit cell metamaterial is constructed; its effectiveness is demonstrated by testing in an acoustic impedance tube. The broadband attenuation characteristics of the constructed unit cell metamaterial are shown to match well with the predicted results. To demonstrate further the effectiveness of the idea, a metamaterial is formed using 4 periodic unit cells and is tested in a twin room reverberation chamber. The transmission loss is shown to improve significantly, at low frequencies, due to the inclusion of the resonators.

Low-frequency noise attenuation of seismic data using mathematical morphological filtering

2017 ◽  
Author(s):  
Weilin Huang ◽  
Runqiu Wang ◽  
Xiaoqing Chen ◽  
Yanxin Zhou ◽  
Yangkang Chen ◽  
...  
Keyword(s):  
Seismic Data ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Low Frequency Noise ◽  
Morphological Filtering
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