The acoustical design and construction of the new Mutual‐Don Lee Broadcasting Studios in Hollywood were done under novel and very favorable arrangements. First, a careful check was made of the optimum acoustical characteristics to which it was decided to design the studios. Some of the best auditoriums for broadcasting were measured, and from these data as well as comments regarding the excellence and shortcomings of these auditoriums, the optimum characteristics for the new studios were determined.During the course of construction, acoustical measurements were made several times for the purpose of “tailor‐making” the acoustical characteristics of the studios. On the basis of the measurements, it was found that only a few minor modifications in acoustic treatment were necessary, such as changing the mountings of the Acousti‐Celotex materials in order to change the low frequency absorption characteristics as desired, and the areas used of these materials.The results are, close agreement between optimum and finally measured acoustical characteristics, and very satisfactory broadcast programs.