The authors have been responsible of the acoustical and architectural design, construction management and final acoustic test of the Legambiente Auditorium in Rispescia (Central Italy). The Auditorium is located in a church intended as multipurpose hall, for conferences, concerts and other events. In the original scenario the high reverberation time made any perceived sound confused and scarcely intelligible. The goal of the project has been to create an acoustically comfortable and versatile space, provided for different types of functions. Solutions have been designed by choosing products that results environmentally sustainable and fully respectful of the architecture of the church as well.