On low frequency sound transmission loss of double sidebranches: A comparison between theory and experiment

Shiu Keung Tang, F. Y C Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review

18 Citations (Scopus)


The sound power transmission losses of various sidebranches installed along a rectangular duct below the first cut-off frequency of the duct are studied experimentally. Special efforts are made to examine how accurately the plane-wave theory predicts the sound-power transmission loss. Four types of sidebranch impedance are established and their effects to the sound power transmission loss discussed. It is found that under the nonresonant conditions the plane-wave theory can give reasonable prediction when the branch separation is large or the original sound transmission loss of the corresponding single side-branch is weak. The theory always overestimates the sound transmission loss at resonant conditions but gives underestimation if the transmission loss is due to the noise breakout in the sidebranches, especially for short branch separation.
Original languageEnglish
Pages (from-to)3215-3225
Number of pages11
JournalJournal of the Acoustical Society of America
Issue number6
Publication statusPublished - 1 Jun 2003

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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