Sentence:  For obvious reasons the percussion is normally arranged along the back of the platform, whether centrally or to one side, and sometimes also in two tiers, the heavy, noisier instruments behind, and the pitched, agile instruments such as vibraphone, marimba, etc. in front. An outstanding exception, however, exists in Roberto Gerhard's "Epithalamion" where the composer expressly desired that the all-important <WSD>kitchen</WSD> department be spread out in front of the strings and hence nearest the audience. 
Meaning of the word marked with <WSD> tags:  The percussion section of an orchestra.