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1945 Theatre Catalog, 4th Edition, Page 343 (319)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 343
Page 343


1945 Theatre Catalog, 4th Edition, Page 343

MOTIOGRAPH

Motiograph-Mirrophonic sound equipment is available in the following five models:

Model M-11, designed for theatres up to 750 seats.

Model M-9-B, designed for theatres up to 1,000 seats.

Model M-911, designed for theatres up to 1,000 seats.

Model M-ll Dual, designed for theatres up to 1,450 seats.

Model M-911 Dual, designed for theatres up to 1,900 seats.

In establishing the above maximum seating ratings, Motiograph has followed the recommendations of the Research Council of the Academy of Motion Picture Arts and Sciences. It has been our experience, however, that the loudspeaker systems we furnish are so far above the average in efficiency that there is ample justification for using these systems in theatres with greater seating capacity.

In Motiograph-Mirrophonic sound systems power amplifiers are measured at 2 percent distortion, with do. excitation in all modelsenot just in more costly models. Electro-dynamic speakers are included in all models as are first quality sound reproducers and matched loudspeaker and amplification systems for perfectly balanced sound.

In the sound reproducer both exciter lamps light at once, giving full brilliance at changeover. The oil shield and drainage system do not let oil get on the sound lens. Helical cut drive gears outwear the worm drive type. Steel and bakelite gears are used throughout, no soft iron or bronze gears being used. Pre-focused exciter lamps allow for instantaneous changeability. Low speed sound sprocket is a protection against flutter. Double pad rollers assure smoother operation. Laminated felt impedance rollers result in low fiutter, long, even wear. The rotary stabilizer gives full protection against flutter. Shockproof drive isolates intermittent movement action. For the side-mounted nontilt motor, no thrust bearings are required. Flutter content is well below Academy limits.

In the loudspeaker system, electrodynamic speakers are used throughout, not those of the light-duty permanent magnet type. Non resonal metal highfrequency hornegives perfect distribution. Full-size low-frequency horns and baffles complete the tonal range.

All Motiograph-Mirrophonic S o u n d Systems produce the same high quality sound reproduction. The five models vary only in the amount of amplification and loudspeaker equipment furnished. Thus the purchaser of the smallest Mirrophonic System can obtain the same quality as the purchaser of the largest system in the line.

The Motiograph-Mirrophonic line is extremely fiexible and is so modern in construction and design that each model is adaptable for the reproduction of any of the proposed forms of dual or control track recording.

A Motiograph-Mirrophonic sound system gives the most natural, lifelike sound ever heard, with heretofore unobtainable delicate shadings of voice, and quality of musical reproduction never before ap 1945-THEATRE

CATALOG

proached. The loudspeaker systems afford the best balanced and the most complete tonal range, with uniform sound distribution throughout the theatre.

Next to quality of reproduction, reliability in operation is most important. All Motiograph-Mirrophonic sound system components are, therefore, designed to give the acme of trouble-free service and can be expected to have unusually long life.

Pre-Amplifiers (Voltage Amplifiers)

The PA-7505nA pre-amplifier (voltage amplifier) is standard equipment in Models'M-9-B, M-911 and M-911 Dual, is Motiograph designed and built and utilizes three low cost vacuum tubes. Individual amplifier tubes are provided for each reproducer. The preamplifier has a single master volume control with auxiliary facilities for balancing reproducer outputs. The changeover switch and volume control are of the highly reliable commutator type. This preamplifier is intended to be located in a control cabinet, mounted between the projectors 0n the front wall of the booth. These cabinets have as associated equipment, extension rods, couplings and knobs, so that changeovers and volume can be controlled from either projector operating position.

The TA-7466-A pre-amplifier (voltage amplifier) standard equipment in Models M-ll and M-ll Dual is Western Electric designed and built and utilizes three Western Electric 310-B vacuum tubes. Individual amplifier stages are provided for each reproducer. These stages include volume control units for exactly balancing reproducer outputs. Repros ducers are coupled to the preamplifier by special coaxial cables which thoroughly shield minute sound currents from interference of all kinds. This preamplifier is intended to be located in a control cabinet, mounted between the projectors

on the front wall of the booth. These cabinets have as associated equipment, extension rods, couplings and knobs so that changeovers and volume can be controlled from either projector operating position.

Power Amplifiers

The MA-7505-A 20-watt power amplifier furnished in Models Ms9-B, M-911 and M-911 Dual utilizes low cost vacuum tubes. Its mechanical design provides exceptional accessibility of all components. The electrical circuit is of the resistance coupled feed-back type. A separate amplifier tube is provided for monitor speaker operation. In Models M-9-B and M-911, one MA-7505-A 20-watt power amplifier is furnished and Model M-911 Dual has two rack mounted MA-7505-A 20-watt power amplifiers operating in parallel to give 40-watt power output.

The switching panel supplied in Model M-911 Dual affords facilities for operating either amplifier alone in the event of emergency.

The TA-7467-A 15-watt power amplifier furnished in Models M-11 and M-11 Dual inclusive of the Motiograph-Mirrophonic Sound System line, is designed, engineered and built by Western Electric Company. The TA-7467-A 15-watt power amplifier is entirely self-contained and compact in the extreme and its mechanical design is such that all component parts are easily accessilie. Each power amplifier utilizes: 3 Western Electric 310-B vacuum tubes, 2 Western Electric 30i0-B vacuum tubes, 1 Western Electric 274sA rectifier tube, and 1 Western Electric 336-A monitor tube.

Any vacuum tube in this amplifier may easily be checked by operating a rotary selector switch, part of the self-contained tube test set. Tube conditions in percent of normal are indicated on the panel meter. All the vacuum tubes are mounted on the top side of the chassis. In this

CENTURY PROJECTOR'S MODEL R-2 REPRODUCER
1945 Theatre Catalog, 4th Edition, Page 343