Renovation of the concert hall The Doelen: A case study on the impact of a stage canopy on stage and room acoustics

Abstract

When opened in 1966, the main concert hall in De Doelen, Rotterdam, the Netherlands, was provided with six canopies above the stage platform. Their function was twofold: to provide a large part of the audience with early reflections; to create good ensemble conditions for the musicians on stage. Despite good reviews after the opening, a few years later the canopies were removed to get rid of unwanted reflections at the recording microphones positions just below the canopy. Since then, a significant percentage of the orchestra is unhappy about the acoustic conditions on stage. During the design process of the renovation, possibilities to re-introduce a stage canopy are investigated. Objective acoustic parameters obtained by carrying out measurements in the hall as well as in a 1:10 scale model and by calculations with a ray-tracing computer model are examined. Parallel, three questionnaire rounds gave an impression about the musicians' subjective judgement about the stage acoustics. In this paper the acoustic differences of three situations (without canopy, with original canopies and with new canopy design) and the search for an optimal balance between improving the stage acoustics without altering room acoustical conditions in the audience are discussed.

Acoustic study of different sceneries at the São Carlos national theatre of Lisbon

“…The resonance boxes of many historical theatres have been heavily damaged being filled with concrete or similar materials in order to allocate machinery for stage changing [9]. This construction element, so meaningful since the design stage, characterizes the acoustics of the whole theatre [11], supporting especially the low frequencies and making the sound deeper other than softer [12]. A schematic section of a generic resonance box has been shown in Figure 3 below, out of scale.…”