Boettcher Concert Hall, opened in 1978, is a 360-degree concert/symphony hall located at the Denver Performing Arts Complex in Denver. Boettcher Concert Hall is the first symphony hall in the United States designed to place the audience close to the stage in a unique environment. Approximately 80 percent of its more than 2,600 seats are within 65 feet of the stage. On each curved surface of the hall is a wave-like band, approximately four feet high, technically called an undulating acoustical facia. These facia diffuse, reflect and channel sound throughout the venue. The seats in Boettcher are custom-designed, made from steam-bent plywood, with their backs varying in height from 42 inches to 48 inches. Boettcher also features a 2,400 square foot stage with 18 removable traps. The stage accommodates up to 120 musicians for large symphonic performances.