A numerical study of the diffusion performance of a terraced classroom

Zhaorong Zhang, Cheuk Ming Mak, Jianliang Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review


The acoustic diffusion performance of a terraced classroom was investigated using a two-dimensional boundary element method. Quadratic residue diffuser (QRD) and porous material were employed on the ceiling and rear wall, respectively, to improve the diffusion performance. The diffusion gains of various models were calculated to compare the diffusion performance. It is found that terraces in a rectangular classroom raise the lowest sound pressure level and provide slight diffusion improvement. The QRD ceiling enhances the diffusion by scattering the sound wave to be more evenly distributed, but at some frequencies the diffusion improvement is minor or even negative. The absorption rear wall provides useful diffusion gain mainly at higher frequencies by absorbing parts of the reflected sound. When the parameters of the QRD ceiling and porous material change, the diffusion improvement first increases and then begins to decrease. In a terraced classroom with both treatments, the diffusion at lower frequencies is similar to that with the QRD ceiling, while at higher frequencies it resembles that with the absorption rear wall. The results clearly indicate that the combination of the two treatments produces the most desirable diffusion performance of the tested models. Hirzel Verlag · EAA.
Original languageEnglish
Pages (from-to)890-899
Number of pages10
JournalActa Acustica united with Acustica
Issue number5
Publication statusPublished - 1 Sept 2011

ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Music


Dive into the research topics of 'A numerical study of the diffusion performance of a terraced classroom'. Together they form a unique fingerprint.

Cite this