Auditorium Shapes.—The shape of the auditorium itself, which used to be invariably a horseshoe, is now most apt to take the form of a fan with convex sides curved in towards the front and rear. An elliptical form has been tried with good decorative effect in the theatre of the Carnegie Institute of Technology, Pittsburgh, Pa. (Alden and Harlow, archs.) and in the Ziegfeld theatre, New York (Urban and Lamb, archs.). The New Cinema, Portsmouth (A. E. Lutte, arch.) is also a good example of this type. The fan with straight sides and a wide splay was used in the Beyreuth Festspielhaus (Manfred Semper, Arch.) where the boxes are located in a straight row across the back of the theatre and the "diamond horseshoe" of boxes eliminated.
Acoustics.—Any divergence in shape from auditoriums tried and tested by time involves the risk, of course, of producing bad acoustics. But the danger is far from absent in any theatre for the problem of acoustics is the most difficult that an architect has to meet. In 1895 Prof. Wallace C. Sabine of Harvard, begin ning by means of formulae and of photographs of sound waves in models of auditoriums, was able to determine in advance with a certain degree of accuracy the acoustic properties of a given design of theatre. Later research has devised methods of correct ing bad acoustics by means of felts, wires, sounding boards, etc., but the fact remains that the best material for the interior of an auditorium, wood, generally cannot be used on account of the restrictions of the fire laws.
Visibility.—A problem of theatre construction which has not had as complete a study and formulation as it deserves is the line of slant in auditorium floor and balconies in relation to the height of the stage. The essential aimed at is the most perfect visibility from every seat in the house. One of Germany's theatre reformers, Littmann, in a desire to give the last row as clear a view as the first, prescribed a very steeply slanting floor, but made the grave mistake of mak ing it merely a straight inclined plane. The result was that the front rows had more range of vision than they needed, while the last rows suffered from the feeling of looking down a nar row tunnel. The better method, which is generally followed to day, is to begin with little or no inclination at the front, and then to increase this radically towards the rear. The slant of the auditor ium and, of course, of the bal conies, too, is controlled in most cities by the requirements of the building regulations. The height of the stage above the auditorium floor is not so restricted, and can be worked out freely to give the whole auditorium a complete and comfortable view of the actors upon the stage. It is often very badly handled.
The slant of the floor and the arrangement of the balconies bring out many interesting pos sibilities. Krapp combined the
"bleacher," "stadium," and "sin gle balcony" types in a so-called "arena" arrangement used experimentally in Chanin's Forty-Sixth Street theatre, New York, and better worked out in another Chanin playhouse, the Majestic, New York. The purpose is to get a very deep orchestra floor by running the entrance foyers under its steeply slanting rear. The Guild theatre, New York, (on a suggestion by Norman-Bel Geddes) managed to place its roomy lobbies under the auditorium without raising the latter so far above the street as to bring it into conflict with the fire regu lations.
The effect of this arrangement is that the spectators are seated in one solid mass. An equally im portant consideration — which should argue a change in fire reg ulations—is that a house seated on the German model can be cleared in half the time it takes an audience to press into and up the ordinary narrow aisles. This German seating arrangement has been used with success in the Kenneth Sawyer Goodman Me morial theatre, Chicago (How ard Shaw, arch.), which happens to be located outside the juris diction of the Chicago fire com missioners.
Stage Lighting from the Auditorium.—The stage ar rangements,except as to adequate dressing rooms, property rooms, and scene stacking space, are mat ters for the theatre technician— scene designer, electrician, etc.—not the theatre architect, although the architect should see that there is ample space allowed. Some thing should be said, however, on one point connected with light ing arrangements ; this is the necessity of providing room in the auditorium for the placing of lights for the illumination of the stage and the actors. In 1914 Granville Barker introduced at Wallack's theatre in New York a row of powerful incandescent lamps around the balcony rail to replace the footlights. David Belasco took the next step forward by installing such lights in a recess in the balcony rail closed by doors automatically controlled from the stage switchboard. Some such provision, or perhaps a light bridge concealed in the ceiling beams, as in the Yale uni versity theatre, New Haven, Conn. (C. H. Blackall, arch.), or the Guild theatre, New York, ought to be a part of every archi tect's plan of a new house.