We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
Page 34
Projection Engineering, June, 1930
New Developments
and
News of the Industry
VARIABLE SKY FILTER TO FIT DUPLEX FILTER HOLDER The Bell & Howell Company announces that it is now ready to make immediate distribution of a graduated Alter glass to fit the B & H Duplex filter holder. This is a segment of glass graduated from clear to 4x density, which permits, for example, the photographing of clouds and sea in combination with foreground without underexposing the foreground. The outstanding value of this filter lies in the fact that it can be used to photograph a composite scene requiring partial correction and at the same time have the facility of giving any degree of correction desired. The duplex holder complete with the 2x and 4x filter glass and the variable sky filter glass may now be had in one combination set which will be known as The B & H combination filter set.
ELECTRICAL TURNTABLE FOR LOW-SPEED RECORDS
For the faithful rendition of the large 16-inch disc records employed for theatre and broadcast purposes, at a minimum investment, the Stevens Manufacturing Corporation of Newark, N. J., has developed a giant electrical turntable and companion electromagnetic pickup.
Briefly, the new Stevens product comprises an 18-inch turntable operating at 33 1/3 r.p.m. Instead of using an elaborate system of driving shafts and gears, the new turntable is driven by a silent and constant speed Stevens-Sibley motor, through a friction drive applied directly to the inner face of the turntable rim. The motor is mounted with a pivotal spring tension, so that the friction drive makes positive contact at all times. An automatic governor is included inside the motor's cast metal shell, thereby maintaining a constant motor speed despite line voltage fluctuations within 25% plus or minus of normal.
R.C.A. APPOINTMENT
Lowell Vere Calvert, for the past five years general manager of Educational Pictures, has been appointed manager of recording operations of RCA Photophone, Inc., to succeed H. L. Sommerer, who returns to RCA-Victor Corporation as managing director of that company's activities in Japan, according to an announcement by Charles J. Ross, executive vice-president of RCA Photophone, Inc. In his new capacity, Mr. Calvert will assume control of the recording operations of RCA Photophone's two studios on the west coast, the Gramercy studio in New York City and at the RCA-Victor plant in Camden, N. J., as well as being the company's representative in its contact with RCA Photophone licensees.
BEST MAGAZINE LIGHT The Best Devices Company, Film Bldg., Cleveland, Ohio, announces the Best Magazine Light, which fits all Simplex projectors. This light permits projectionists to see the amount of film in upper magazine without the opening of magazine door. The reel may be observed from either side of the projector. It is cast of aluminum, lacquered black to match magazine finish. Easily mounted. No holes to drill.
PHOTO-VOLTAIC CELL SOLD
Samuel Wein, of New York City, has sold his interest in the photo-voltaic cell to the Radiovision Corporation. New York. Mr. Wein is now engaged in consulting engineering for various manufacturing companies.
NEW EXECUTIVES JOIN SOUND STUDIOS OF NEW YORK
A. J. Kendrick, president of Sound Studios of New Y'ork, Inc, announces the appointment of John Valentine as assistant sales manager and Charles Hathaway as account executive.
Mr. Valentine comes to Sound Studios of New York from the Judson Radio Program Corporation, where he held a position similar to his present one.
A S. S. W. MOLDED RESISTANCES
A new type of resistance unit, which has many advantages, characteristics and qualities, is a product of tire research laboratory of The S. S. White Dental Mfg. Company, Industrial Division, 153 W. 42nd St., New York City.
The S. S. W. resistance units are molded from special binder and conducting material, the finished
units being non-hygroscopic. Their strength insures them against breakage and all end contacts and lugs are molded perma'ncntly into the resistance material. They have a positive coefficient of heat and are thereby insured against self destruction through overloading. The nature of the resistance material is such that they will not change in resistance value when used within their rated wattage.
At present, they are supplied in two standard types, five flat types and one special hexagonal type, rated at 1 watt, 1.25 watt and 3. watts. Units of large capacity are in process of development and manufacture.
AMERICAN SALES COMPANY ISSUES NEW BARGAIN BULLETIN
The American Sales Co., 19-21 Warren Street, New York City have recently issued a Bargain Bulletin No. 60.
Projectionists, engineers, recording laboratories and technicians should send for a copy of this bargain bulletin which includes numerous parts, such as filter chokes, power transformers, filter condensers, etc.
They are now featuring the Kolster K-5 -dynamic speaker with built-in 210 (or 250) power amplifier in walnut cabinet at a special price of $24.50 each, same listing for $175. (less tubes).
This speaker can be used very successfully in all indoor, outdoor and theatrical installations of speakers.
A VENTILATE THE BOOTHS
In these days there is no excuse for uncomfortable, poorly ventilated projection rooms. There is available a dependable ventilating unit consisting of motor and fan blower (see illustration) which exhausts 500 to
800 cu. ft. of air per minute. This approved, economical unit is manufactured by The Davenport Mfg. Company, Meadville, Penna.
PRECISE SERIES RESISTANCE FOR EASY PROJECTOR STARTING
Many projectionists have trouble with the starting of projectors. Unless the motor starts slowly and positively, the projector and its associated sound equipment is subjected to severe strain. Some equipment manufacturers provide fixed series resistors, but these often fail to provide the correct resistance value, and may even fail to stand up under load.
Recently consulted on this problem, the engineering staff of the Clarostat Manufacturing Company, Brooklyn, N. Y., recommended the Super-Power Clarostat — ■ a giant adjustable resistor providing a wide range of resistance in several turns .of its knob. Tests have confirmed the soundness of the recommendation. Employed as a series resistance, the clarostat may be set for any satisfactory value to insure the slow, positive starting of the motor, minimizing the strain on the projector and associated sound equipment. A three-point snap switch is employed for turning on and off the current, and inserting or eliminating the clarostat resistance from the motor circuit. Once the satisfactory resistance value is determined by actual test with the particular motor to be controlled, the clarostat is left alone, maintaining that resistance setting with the certainty of a fixed resistance. Meanwhile, the 250-watt capacity of the device is more than ample to dissipate the heat generated. Both snap switch and clarostat may be mounted in an iron box, or the device itself may be mounted in a separate box.
A
TESTS, INSTRUMENTS AND MEASUREMENTS
Every sound engineer, technician and worker should procure the monthly issues of the "Research Worker"
published by the Aerovox Company, 70 Washington Street, Brooklyn, N. Y.
This publication contains technical information of immediate and direct use to every man in the business. The Aerovox Company will upon request send the monthly issues of the "Research Worker" to every reader of PROJECTION ENGINEERING.
A PORTABLE TALKING PICTURE MACHINE
The Audivision Corporation of 1775 Broadway, New York City, is marketing a 16-mm. sound-on-disc talking picture machine. The projector and turntable are in a carrying case 19" x 16" x 13" and the amplifier and speaker are in a case 10" x 11" x 13". A 3' x 4' picture can be shown at a distance of 15 feet. Separate units are made for 78 and 33 1/3 r.p.m. 16-inch discs. Although of rugged construction, the total weight of both units is only sixty pounds. The speaker unit is adapted for use with a microphone and the amplifier is of sufficient capacity to operate several loudspeakers, making in itself a complete publicaddress system. The machine is not complicated and adapted to use in the home by inexperienced operators as well as for commercial and industrial use.
CONTINENTAL ACCESSORIES PLANS THREE MORE OFFICES
With the dedication of the new Warner edifice in Chicago to tenant all subsidiary companies, Continental Theatre Accessories will soon open a third branch in this building. Plans are also understood under way for opening offices at St. Louis and Pittsburgh. Harry M. Warner and officials of the company were in Chicago to attend the ceremonies.
AN ATTRACTIVE TELEVISION BOOKLET
So little is understood and so much is misunderstood regarding television that a booklet entitled "Television — The Eye of Radio," is most welcome at this time. Under this title, the Jenkins Television Corporation of Jersey City, N. J., has published an attractive booklet of 32 pages and cover, which contains a conservative, interesting, readily understood discussion of just what television is, what has been done so far, what is being done for the future, and why the television experiment is about to develop into the television industry. The booklet contains photographs and descriptions of the equipment about to be introduced for home use, as well as the television studio and transmitting equipment. A copy is free for the asking.
NEW BURTEX DIAPHRAGM
After months of intensive development, Clifford E. Stevens, chief engineer of Stevens Mfg. Corp., Newark, N. J., announces a new burtex or impregnated cloth diaphragm available in any size, shape or degree or stiffness.
The new burtex diaphragm, according to Mr. Stevens, is provided with a special waterproof finish. Tests indicate that the diaphragm can hold water for 50 hours without sign of leakage. Not only is the diaphragm impervious to moisture, but it is unaffected by heat, cold, salt air and other climatic conditions. It is considerably lighter than the burtex diaphragms heretofore available, yet it can be made in any desired weight or stiffness to meet specific requirements. The more flexible diaphragms are generally required for more sensitive speakers producing soft anj mellow speech and music, while the stiffer diaphragms are used to obtain sharp, crisp, sparkling music ana speech. Any weight is available for the desired resonance and response.
A new mechanical design has also been provided, in the form of a diaphragm with concentric rings starting some distance from the apex and continuing past the mask and to within an inch of the mounting rim. The concentric rings are slight corrugations. The acoustic results are truly startling.
NEW MONITOR PANEL Jenkins & Adair, Inc., 3333 Belmont Avenue, Chicago, Illinois, announces the Type C monitor panel which is the latest means for audible monitoring on broadcast or recording circuits. The bridging amplifier used is so designed as to cause a minimum of attenuation when the monitor circuit is across the line. This small attenuation is practically uniform for all normal frequencies.