Broadcasting (Oct 1931-Dec 1932)

nical supervisor, who is as much at home in machine shop or draughting room as he is behind a control panel. At the remote transmitting plant, sectionalized towers of unique construction are so efficient that nearly fifty letters from New Zealand and other remote points are on file, although the power radiated is only 1,000 watts. A complete spare transmitter is available for emergencies. Long noted for its civic activities, WHK has been particularly successful in a virgin field, that of broadcasting school courses to grade pupils. More than 5,000 of these now listen four times weekly to arithmetic lessons sponsored by the Cleveland Board of Education, and a beginning has just been made in elementary music. Notable also are new liaisons effected with Cleveland College, which offers daily lectures and weekly musical programs, and with Oberlin College, 45 miles distant, which will broadcast programs by faculty and students weekly throughout the year. This has been accomplished by "floating" construction, as though each studio were a large box slipped inside a slightly larger one, leaving a dead air space between the the two. Walls, ceilings and floors are hung on springs, and for the first time the floors are of concrete rather than wood or other light material. "Acoustone," a gypsum compound in the form of tiles, in various shades, is the treatment used throughout on walls of the studios, corridors and entrance lobbies. This dispenses entirely with drapes or movable devices to control reverberation. Floors of all studios are linoleum tiles laid directly on the concrete. Conditioned air is supplied to the new quarters through a special system. Not only does this insure the comfort of artists and visitors, but it simplifies the tuning of instruments. This is of most importance in the case of the giant organ, which is adapted to both concert and theater types of rendition. Air enters at the top of each room and is drawn out at the bottom through tubes that are equipped with sound filters. Only "dynamic" microphones, so new that they had to be put through the Bell Laboratories model shop on special order, are being used by WHK. In the larger studios these compact instruments are suspended from cables that run through the ceiling to motors operated from the control room. Thus it is possible for an operator to move microphones up or down or sideways by means of piano-wire guys through other ceiling orifices. An arrangement of this sort facilitates rehearsal of a program, since the director can lead his men through the control room window, listen to their output on a loud speaker there, and, if occasion requires, talk to the musicians through a reversible speaker-microphone setup. Piping the Programs OCCUPANTS of each office listen to WHK programs through speakers which are individually controllable as to volume. Most of those used are of the new Rochelle crystal type, and the same devices are scattered throughout the Higbee store, with switches and volume adjustments in the station's master control room. Elimination of batteries is an innovation in the station, which now trolled and arranged to switch into main line or channel operation in the same manner as a remote pickup or CBS feature. Output of the microphones is led to faders of six channels each in the largest two studios and of three channels in the other four. The faders are of special construction, with vertical rather than rotary motion. They can be adjusted very quickly and their position as readily noted. From the faders, progress of the signal current is through a twotube booster amplifier, to a variable attenuator for gain control, and then to a switch enabling transfer from line operation to audition, or vice versa. The output of all microphones is paralleled to the main control room, so that any studio can be set up and operated from main control, independent of studio control. All amplifiers have a flat frequency response of from 30 to 10,000 cycles. Combined with improved telephone circuits to the 5,000-watt transmitter south of Cleveland and to the dynamic microphones, they give markedly high quality of output. Those who study the accompanying floor plan and dimensions will note that all studios conform very closely to the 2-3-5 formula (for height, width and length) which has been worked out by acoustic W0MLN S-T0ILLTS ■ MENSTOILETSWOMEN • ARTISTS • Ct-ILCK, ROOM ■ LOCkLLR. R.0OMANUOUN'CLRS" DRAMATIC DIRECTOR. • OR.GKNIST orncL STUDIO STORAGE; STORAGE;. TERMINAL TOUJlR-> •E.NTR.AWCL claims to be the finest in the world. Originally they were specified as emergency equipment, but since direct as well as alternating current is available a motor-generator set will be used in case the alternating power fails. Switching from one power source to the other is automatic. Each studio is set up as a separate unit. It is individually con engineers as best adapted to reproduction of sound. All studios, audition, control, reception, observation and announcers' rooms are tied together by a telephone system with automatic call-light signalling equipment Dials are of special construction tc insure silent operation. The Howlett "trio" is composed (Continued on page 3U) Page 12 BROADCASTING • December i, 1931