Journal of the Society of Motion Picture Engineers (1930-1949)

Record Details:

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1950 MAGNETIC SOUND FILM 503 carrying a flywheel because inertia is added to the film which, itself, is virtually without mass. This procedure has been followed in the camera illustrated by Fig. 6 with the additional arrangement that the flywheel drum has been constructed with an annular recess within which the magnetic heads are accommodated. The arrangement is such that the magnetic layer faces the drum while the film is supported on the outer parts only, the middle portion of the film, that is, the part covering the recess, being without any other support except for that of the curved surface of the magnetic heads which are located inside the cylindrically shaped portion of the film passing round the drum. In cross section the flywheel drum is H-shaped, the horizontal bar of the H coinciding with the drum axis, the space above and below the axis being occupied by the heads, which are supported on rigid arms placed in such a way as not to interfere with the passage of the film through the apparatus. The ends of the arms remote from the m Fig. 6. Magnetic sound film camera with the magnetic heads mounted inside the recording drum.