The Italian historical theatres have been built to blend the singer voice and the orchestral sound in the melodrama. In order to arrange the different scenes required by an opera representation, these theaters have a large volume in the stage section. Thus the stage volume may be oversized compared to the one of the orchestra pit. The paper study the musician’s perception in the Masini Theatre of Faenza when the stage is used by symphonic orchestras or smaller groups, making also the reference to similar literature concerning different theaters shapes. The impulse responses on stage have been measured and the monaural normal descriptors have been extracted. Numerical models of the stages are implemented in a hybrid ray tracing software and an acoustic shell is designed. Questionnaires have been submitted to professional musicians and the answers have been statistically resumed. Hence acoustical measured descriptors, simulated values and musician answers are related and discussed.