The Des Moines Symphony in partnership with Des Moines Performing Arts next week will unveil phase one of an acoustic project – a new orchestra shell. The shell will debut Sept. 26 and Sept. 27 at the symphony’s season opening concerts. This phase of the project includes three primary enhancements: a maple veneer shell with a curved shape to project sound more effectively to both orchestra musicians onstage and to the audience; cloth-covered felt and hardboard panels that cover the side walls in the hall and absorb higher frequencies to produce clearer sound; and textured, reinforced gypsum board along the back wall to make the sound from stage more resonant. The shell was designed by Joseph Myers of Kirkegaard Associates and made possible with support from Principal Financial Group Inc.,W.T. & Edna M. Dahl Trust and Prairie Meadows. More information on the Symphony’s Season Debut concerts can be found online.