THE SPECIFICATIONS AND OPERATION OF BOULDER CITY'S DIVISIBLE AUDITORIUM ARE PRESENTED. IN 1956, WITH THE THREAT OF A SHARP ENROLLMENT INCREASE, CONSULTANTS WERE BROUGHT IN TO BOULDER CITY TO DEVELOP SPECIFICATIONS FOR A PROPOSED NEW BUILDING. THE POTENTIAL NEED FOR MORE INSTRUCTIONAL SPACE HAD TO BE RECONCILED WITH THE EXISTING NEED FOR AN AUDITORIUM. THE BUILDING HAD TO HAVE AUDITORIUM-ASSEMBLY SPACE AND LARGE-GROUP INSTRUCTION SPACES AND ALSO HAD TO HAVE A UTILIZATION FACTOR HIGH ENOUGH SO THAT THE BUILDING COULD ACT AS A HEDGE AGAINST FUTURE BULGES IN ENROLLMENT. BEGINNING WITH A CONVENTIONAL AUDITORIUM, THE PLANNERS DESIGNED A WEDGE-SHAPED SEATING AREA DIVIDED FIRST BY AN AUDIOVISUAL CORE BISECTING THE WIDE END OF THE WEDGE, AND THEN BY TWO MOVEABLE PARTITIONS SEPARATING THE REAR ALCOVES ON EITHER SIDE OF THE AUDIOVISUAL CORE FROM THE MAIN SEATING AREA AT THE FRONT OF THE AUDITORIUM. BECAUSE THE NEW FACILITY CAN BE DIVIDED AT WILL AND AT ONCE, IT LENDS ITSELF TO TYPES OF INSTRUCTION FOR WHICH A STANDARD AUDITORIUM WOULD BE TOO LARGE, A STANDARD CLASSROOM TOO SMALL. THE PARTIAL SUBDIVISIONS CREATED BY A PERMANENT SPILT-LEVEL CORE WIH AUDIOVISUAL WORKSHOP ABOVE AND LOBBY BELOW IS COMPLETED BY TWO OPERABLE WALLS, WHICH BLOCK SOUND SO EFFECTIVELY THAT ALL THREE SUBDIVISIONS CAN BE USED AT THE SAME TIME. THE RESULTING FLEXIBILITY BOOSTS THE UTILIZATION OF THE BUILDING FROM THE 10 PERCENT WHICH IS USUAL FOR A HIGH SCHOOL AUDITORIUM, TO A POTENTIAL APPROACHING 100 PERCENT.