Recent work which established the acoustical conditions for ease of ensemble on stage [A. H. Marshall, D. Gottlob, and H. Alrutz. J. Acoust. Soc. Am.64, 1437–1442 (1978)] has been applied in two designs for arena stages. The first design has been constructed in the existing Christchurch Town Hall [A. H. Marshall, J. Acoust. Soc. Am.65, 951 (1979)]. A set of surfaces based on the reported work was installed above and around the stage in May 1978. At the first concert following, critics noted the excellence of ensemble playing and a questionnaire to the orchestra, which previously had expressed some difficulty with ensemble, elicited an overwhelmingly favorable response. The second part of the paper reports progress on the design of the stage and “ensemble” surfaces in the Wellington Town Hall. General conclusions about the design of arena stages for orchestral use are drawn.