Had it not been for the structure of the room under the auditorium, Mr. Ewald would have constructed the entire floor on a steel frame, as described above, and balanced it on an axle at the center, where the hinges now are. With suitable space under the front half of the floor, it could have been tipped on its axle, depressing the front and elevating the back, giving an incline to the entire auditorium. Built thus, the floor would require no jack and would be amply supported at three points; or, with the understructure built in the form of a truss, the floor could be made to rock on the apex of the truss. With this arrangement, the front half of the floor would have support along its entire length.
Figure 5—First-floor plan of the Munich Art Theatre. Note that the seats shown here form only a part of the main floor section, as indicated in the plans on the page opposite. Max Littmann, Architect.
Figure 6—Above is a section showing the arrangement and structural features of the Munich Art Theatre. Below is the second-floor plan. It should be noted that the seats here are not a balcony but a continuation, on the same floor slope, of the seats shown in the plan on the page opposite.
Another device, proposed for a great municipal auditorium in a western city, will not so readily commend itself for general use, because of the great initial cost and because of the depth of cellarage required under the auditorium. Here the entire floor was to make a semi-revolution. On one side of the revolving plane was a smooth flooring; on the other, seats were bolted. When the building was to be used as a theatre, the side with the seats was turned uppermost and held at the proper pitch. When the hall was used for a ball or for a dog show, or any function needing a level floor, the smooth side was turned up and secured at a horizontal position.
When the floor can be built with a permanent slope, either a simple incline or an incline in the form of a parabolic curve is used. The latter form is preferable.
In many places the fire laws limit the pitch of the floor to one inch per foot. With rows of seats spaced at the legal minimum of thirty-two inches this does not give enough clearance for the people in each row to see over the heads of those in the row in front. For a decent degree of comfort, a little seating capacity should be sacrificed, and the rows spaced thirty-six inches apart.
If possible, there should be a gradient of two inches to the foot, giving a difference of elevation between rows of six inches. If the law prevents the two-inch grade, the same effect can be produced by “staggering” the seats. That is, the seats of alternate rows are set in direct alignment, while the intermediate rows are set half a seat-width to the right or left. Thus spectators will look between the shoulders of those immediately in front of them, and will be able to see over the heads of those in the second row in front, who, by such an arrangement, will be sitting in a direct line with them. There will thus be a six-inch difference between each two rows of seats.
Beyond all these considerations of adequate sight lines, however, there is another requirement far more important, far less well understood, even in the light of any guiding or misguiding tradition, by the average architect. That is the requirement of good acoustics. Until quite recently, this was left wholly to accident. Buildings were erected, and the acoustic properties were tested afterwards. If they chanced to be good, the owners were to be congratulated. If they were bad, great sums were spent stringing piano wires, or nets of raw silk, or padding the walls. And then, quite as often as not, the acoustics remained bad.