On the 13 – 14 May I participated in the Institute of Acoustics (IoA) Annual Conference Acoustics 2019 presenting my research “How architectural design of stages influences stage acoustic parameter values”.
This research has been developed in collaboration with the Environmental Building Department at the University of Catania (Italy) and the Environmental Built Department at the TU/e Eindhoven University of Technology during my last year of the master’s degree in civil engineering and architecture.
The research discussed the subjective impressions of stage acoustics by musicians in a full orchestra and objective parameters related to it. The study has arisen from a problem: architectural choices for the design of stages versus the acoustics requirements and the needs of musicians. Consequently, the goal of the study was to find possible solutions for the design of concert hall stages, optimising their physical descriptor STearly,d, and to validate this parameter extension.
This new parameter STearly,d takes into account the strength of early sound reflections during a concert. The orchestra needs the early reflections because they contribute to raise the sound pressure level for players on stage. The sound pressure level, in fact, is attenuated by the orchestra itself, masked by the sound power level of other instruments (since percussion and brass are 10 dB louder than strings and 5 dB louder than woodwind instruments) and influenced by the different positions of the instrument sections on the stage. Early reflections are consequently beneficial to the musicians. Strings for instance need stronger early reflections than percussion, woodwinds or brass sections.
I modelled different stage configurations of the same orchestra layout using architectural common features of existing concert hall stages and researched the correct positions of reflective surfaces (reflectors), and the correct materials and floor surfaces on the stage for each instruments’ section.
The solutions proposed may bring a new approach to optimise stage acoustics in concert hall design. In addition, it has been validated that the STearly,d parameter is helpful in understanding the change in the perception of the sound from the musicians’ point of view due to changes in some architectural features.
The research could help designers better understand the acoustics requirements of orchestra members depending on their instruments and the impact that the stage design can have on the quality of music for the audience.
After presenting my research to the delegates, questions included a discussion on the use of an acoustically transparent floor (metal mesh grid) in order to increase the amount of early reflections coming from a second deeper floor under the mesh grid, and the use of Perspex reflective walls in the middle of the orchestra in order to provide early reflection but also visibility between the musicians.
In addition, questions from the delegates included a discussion on the applicability of the method in real life. The research on this parameter is still in progress, however the method is well established, and in the future it might be applicable for the design of concert hall stages.
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