Broadcasting (Oct 1931-Dec 1932)

Miniature But Sensitive Microphone Makes Air Debut in Philco Program Moving Coil Principle Used in Electro-Dynamic Instrument Devised for Stokowski THE ELECTRO-DYNAMIC microphone, midget of the mike family and newest product of the research laboratories, has made its air debut. The microphone, employing the moving coil principle, picked up the strains of Leopold Stokowski's Philadelphia Orchestra on Oct. 12 in the first of the new Philco concerts. The program was transmitted over a 71-station hookup of the Columbia Broadcasting System through an electrical circuit at every point of which new equipment had been installed, involving in several cases the use of apparatus never previously linked up for a broadcast. It originated in the Philadelphia Academy of Music Hall, following exhaustive tests to ascertain the acoustical properties of the hall. The moving coil principle used in the new microphones is said to entail a number of advantages, which were summarized by CBS as follows : "It gives an approximately uniform response over the complete band of audible frequencies, that is, from 20 to 10,000 cycles per second ; "Its transmission characteristics are not affected by variations in temperature, humidity, or barometric pressure — a matter of extreme importance in such broadcasts as those by the Philadelphia Orchestra, where all three of these factors are likely to change during a concert and can not be controlled in the studio. SIZE IS CONVENIENT "ITS SMALL size, as compared with the dimensions of microphones now in use, makes it more convenient to mount in any desired location in the hall in a relatively inconspicuous manner; "It is used at a considerable distance from the amplifier, so that the latter is put in a special location on the stage of the hall for these broadcasts." The signals picked up by the microphone will pass to a control booth on the stage but out of sight of the audience. Although this structure is only seven feet square, it weighs one and one-half tons and is sound insulated with especially worked out acoustic properties. In it is located the speech input equipment. This equipment, according to CBS, is capable of delivering, if necessary, two and a half times as much power without distortion and is far superior to the old type apparatus. MONITORING UNNECESSARY THE monitoring equipment has been designed to operate with a volume range of 40 decibels, corresponding to a power ratio of 1 to 10,000. Within this range— half t as great again as that possible with present apparatus — no monitoring will be necessary; for a fortissimo, a slight change will be made, but in every case the engineer will be thoroughly familiar with the work, will know when the passage is coming, and will make the adjustments gradually in such a way that it will be imperceptible to the comparatively insensitive human ear, and thus normal perspective will be afforded. The monitoring engineer will be stationed in this booth, with a desk panel in front of him, bearing the galvanometer which shows the variation in power passing through the circuit. Above this is the glass observation window through which he can see Stokowski conducting the orchestra though he will not hear the music directly. On the music stand at the conductor's rostrum will be a second galvonometer registering the current variations so that Stokowski will be aware at every moment while conducting of the interrelation between the orchestral volume and the volume transmitted. A system of signal lights has been installed to insure coordination between the conductor and the engineers when a number is to begin and at other times. Census Reveals Radio's Hold on Country (Continued from Page 15) What, then, do the figures show ? The percentage of American homes that are radio-equipped in the states thus far reported runs slightly over 33, or a little better than one out of every three homes. One out of every three homes in 44 states and the District of Columbia, it appears, have radios! Some states show substantially better proportions, others substantially lower. But with one out of every three homes having radios, with all the seasonal and diurnal attractions and distractions radio meets, with all the counter-attractions that radio must combat, with all the "intellectual aversions" oft expressed toward radio — with all these indisputable factors retarding the building of a constant and assured radio audience, there still is tremendous audience! There is audience enough to make radio perhaps the most potent editorial force in the history of mankind. There is audience enough to sway the political mind of constituency and nation. There is audience enough to render negligible state and sectional prejudices, dialects and whatnot. There is audience enough to make radio one of the greatest merchandising and sales forces ever brought within the province of the advertising fraternity. What will radio's power be when the saturation point is more nearly approached? Roughly, the northeastern, middle western and far western states show the highest totals and highest ratios to date. Generally, it may be Radio Call Saves Life A RADIO call for volunteers recently saved the life of James Wotten, of Richmond, Va. Wotten's physicians decided late one day that he required an immediate blood transfusion, and an appeal was broadcast over WRVA. For the next several hours the hospital received more than 200 offers, telephone calls coming not alone from Richmond but from Norfolk, Ashland, Virginia Beach and other outlying towns. Some 70 persons visited the hospital. After the transfusion the patient was reported recovering. said that the states rank in radio very closely to their rank in the national economy. Thus we find the six New England states showing, as a whole, that 49.6 per cent of their homes have radios, about one out of two. We find the middle western states running well into the 40 per cent column, the far western states varying from California's 51.9 per cent to Idaho's 30.3 per cent. POTENTIAL AUDIENCES BUT we find, in the states thus far reported, that there is an average of 4.1 persons per family. This factor varies from 3.5 in California to 4.9 in North Carolina. So to compute the potential radio audience for each state, the average number of persons per family must be used as the multiplier of the total number of homes equipped in that state. Each state's figures being broken down by counties and communities within each state, the potential reasonable and regular audience of each station can easily be computed, given the power of the station and its wave length. The factor of station popularity, of course, no one can guess beyond the results of impartial surveys which more and more stations are having made. All the census figures can show is the irreducible minimum of radio set ownership in any station's area of coverage. Up to the present writing, Massachusetts leads all the states reported with the 57.6 per cent proportion of radios to homes it shows: Rhode Island, with 57.1 per cent, is a close second; Connecticut, with 54.9 per cent, third; the District of Columbia, with 53.9 per cent, fourth; California, with 51.9 per cent, fifth; Wisconsin, with 51.1 per cent, sixth ; Michigan, with 50.6 per cent, seventh; Iowa, with 48.6 per cent, eighth; Nebraska, with 47.8 per cent, ninth, and Ohio, with 47.7 per cent, tenth. The rankings in total numbers of families with radio are somewhat different, of course, due to wide variances in population. California takes the lead, with 839,991 of its families reporting radios; Ohio is second, with 810,767; Michigan is third, with 599,196; Massachusetts is fourth, with 590,105; Wisconsin is fifth, with 364,425; Indiana is sixth, with 351,540; Missouri is seventh, with 322,252; Iowa is eighth, with 309,237 ; Minnesota is ninth, with 287,880, and Texas is tenth, with 257,686. WIL Requests Writ to Restrain KFWF STATION WIL, St. Louis, has petitioned the Supreme Court of the District of Columbia for an injunction to restrain KFWF, St. Louis, from changing its location to the Hotel Jefferson. The suit is against the Federal Radio Commission, which authorized the removal. WIL is an applicant for full time operation on the 1200 kc. channel with 100 watts and now shares the assignment with KFWF. Examiner Elmer W. Pratt recently recommended that WIL be given full time and that KFWF, operated by the St. Louis Truth Center, Inc., be removed from the air. In the petition it is claimed that until the Commission acts on the Pratt recommendation KFWF should not be authorized to change its location. The Commission Oct. 13 denied the motion of WIL to have rescinded the decision authorizing KFWF to move locally, holding it already had decided KFWF should remain on the air. An answer to the appeal of WMBJ, of Pittsburgh, removed from the air last January for failure to serve public interest and violation of regulations (Court of Appeals No. 5349) has been filed by the Commission. Oral arguments were presented before the court on Oct. 5, with Duke M. Patrick, assistant general counsel, appearing for the Commission, and Nathan B. Williams representing the appellant, the Rev. John W. Sproul. Station KECA, Los Angeles, through attorneys Louis G. Caldwell and Arthur W. Scharfeld, filed a brief in its appeal attacking General Order 102, with respect to quotas (Court of Appeals No. 5445). These lawyers previously had filed with the court a similar brief, which attacked not only the validity of General Order 102, but the constitutionality of the Davis equalization amendment, in behalf of Station WPTF, Raleigh, N. C. (Court of Appeals No. 5444). Invents New Radio Tube A NEW filamentless radio tube, said to be as efficient as the threeelectrode bulb as amplifier, rectifier and oscillator, has been invented by Dr. August Hund, of Wired Radio, Inc., Ampere, N. J. These tubes, which can be manufactured for a few cents each, according to trade information, already have been applied exclusively in a three-tube set with satisfactory results. They are said to have a high amplification factor, and are simple and easy to make. They have also been employed in test transmitters and, having negligible internal capacity, can be worked directly on short waves even below one meter. Wired Radio is a subsidiary of the North American Company, which controls public utility properties in various parts of the country. For eight years this company has been experimenting with wired radio as a possible competitor of space broadcasting. The company, headed by Clinton W. Hough, also owns the Associated Music Publishers, Inc. Page 16 BROADCASTING • October 15, 1931