Spectrally smooth and spatially uniform sound radiation from a thin plate structure using band gaps

Jaesoon Jung*, Cheol-Ho Jeong, Jakob Søndergaard Jensen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

As an alternative to conventional loudspeakers, panel loudspeakers have been investigated. However, it is challenging to avoid structural modes in a panel loudspeaker, which results in an uneven frequency spectrum and highly directional sound radiation. Here, we present a technique to eliminate modes in a frequency range of interest based on a band gap (BG) structure that forbids the propagation of waves. In order to open a BG between 300 and 500 Hz, a thin aluminum plate with periodic resonators is considered. Using finite element (FE) simulations, vibro-acoustic responses of the BG structure are analyzed, leading to more spectrally smooth and spatially uniform sound radiation. Experimental results agree well with the numerical predictions, displaying a smoother frequency spectrum and smaller variation of sound pressure at six different measurement orientations in an anechoic chamber. For this specific case, the overall SPL is amplified by 5.5 dB and the standard deviation is reduced by 5.7 dB at frequencies ranging from 300 Hz to 500 Hz.
Original languageEnglish
Article number115187
JournalJournal of Sound and Vibration
Volume471
Number of pages17
ISSN0022-460X
DOIs
Publication statusPublished - 2020

Keywords

  • Band gap
  • Flat panel loudspeaker
  • Sound radiation
  • Vibro-acoustics

Cite this

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title = "Spectrally smooth and spatially uniform sound radiation from a thin plate structure using band gaps",
abstract = "As an alternative to conventional loudspeakers, panel loudspeakers have been investigated. However, it is challenging to avoid structural modes in a panel loudspeaker, which results in an uneven frequency spectrum and highly directional sound radiation. Here, we present a technique to eliminate modes in a frequency range of interest based on a band gap (BG) structure that forbids the propagation of waves. In order to open a BG between 300 and 500 Hz, a thin aluminum plate with periodic resonators is considered. Using finite element (FE) simulations, vibro-acoustic responses of the BG structure are analyzed, leading to more spectrally smooth and spatially uniform sound radiation. Experimental results agree well with the numerical predictions, displaying a smoother frequency spectrum and smaller variation of sound pressure at six different measurement orientations in an anechoic chamber. For this specific case, the overall SPL is amplified by 5.5 dB and the standard deviation is reduced by 5.7 dB at frequencies ranging from 300 Hz to 500 Hz.",
keywords = "Band gap, Flat panel loudspeaker, Sound radiation, Vibro-acoustics",
author = "Jaesoon Jung and Cheol-Ho Jeong and Jensen, {Jakob S{\o}ndergaard}",
year = "2020",
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language = "English",
volume = "471",
journal = "Journal of Sound and Vibration",
issn = "0022-460X",
publisher = "Elsevier",

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TY - JOUR

T1 - Spectrally smooth and spatially uniform sound radiation from a thin plate structure using band gaps

AU - Jung, Jaesoon

AU - Jeong, Cheol-Ho

AU - Jensen, Jakob Søndergaard

PY - 2020

Y1 - 2020

N2 - As an alternative to conventional loudspeakers, panel loudspeakers have been investigated. However, it is challenging to avoid structural modes in a panel loudspeaker, which results in an uneven frequency spectrum and highly directional sound radiation. Here, we present a technique to eliminate modes in a frequency range of interest based on a band gap (BG) structure that forbids the propagation of waves. In order to open a BG between 300 and 500 Hz, a thin aluminum plate with periodic resonators is considered. Using finite element (FE) simulations, vibro-acoustic responses of the BG structure are analyzed, leading to more spectrally smooth and spatially uniform sound radiation. Experimental results agree well with the numerical predictions, displaying a smoother frequency spectrum and smaller variation of sound pressure at six different measurement orientations in an anechoic chamber. For this specific case, the overall SPL is amplified by 5.5 dB and the standard deviation is reduced by 5.7 dB at frequencies ranging from 300 Hz to 500 Hz.

AB - As an alternative to conventional loudspeakers, panel loudspeakers have been investigated. However, it is challenging to avoid structural modes in a panel loudspeaker, which results in an uneven frequency spectrum and highly directional sound radiation. Here, we present a technique to eliminate modes in a frequency range of interest based on a band gap (BG) structure that forbids the propagation of waves. In order to open a BG between 300 and 500 Hz, a thin aluminum plate with periodic resonators is considered. Using finite element (FE) simulations, vibro-acoustic responses of the BG structure are analyzed, leading to more spectrally smooth and spatially uniform sound radiation. Experimental results agree well with the numerical predictions, displaying a smoother frequency spectrum and smaller variation of sound pressure at six different measurement orientations in an anechoic chamber. For this specific case, the overall SPL is amplified by 5.5 dB and the standard deviation is reduced by 5.7 dB at frequencies ranging from 300 Hz to 500 Hz.

KW - Band gap

KW - Flat panel loudspeaker

KW - Sound radiation

KW - Vibro-acoustics

U2 - 10.1016/j.jsv.2020.115187

DO - 10.1016/j.jsv.2020.115187

M3 - Journal article

VL - 471

JO - Journal of Sound and Vibration

JF - Journal of Sound and Vibration

SN - 0022-460X

M1 - 115187

ER -