The main goals for this study were to better understand what are the acoustic conditions physically within a symphony orchestra on concert hall stages, how these physical conditions affect the players and ultimately how to design venues suitable for symphony orchestras. This was investigated through questionnaire surveys and dialogue with musicians, scale and computer modelling and measurements of existing stages. The results from the orchestra collaborations indicate that the impressions of acoustic conditions are related to complex perceptual effects. When relating these effects to acoustic conditions, a narrow and high stage enclosure with the stage highly exposed to the main auditorium appears most beneficial. Existing methods for assessing the stage acoustically by use of omnidirectional transducers without the orchestra present were found to have only limited relevance to perceived conditions. New methods and objective architectural measures have been proposed. The architectural measures successfully discriminate the most preferred from the least preferred stages of purpose-built concert halls. The results from judgements of existing stages support the finding of a narrow and high stage enclosure with a highly exposed stage being most beneficial. How to improve the assessment of acoustic conditions on stage is discussed. Copies of the thesis written in English can be obtained from Jens Jo/rgen Dammerud. E-mail address: jjdamm@gmail.com. 4