This standard specifies the width of the six-track magnetic soundtrack on a 70mm 5-perforation film distribution copy, as well as the position and width of the gap between the recording head and the sound reproduction head. This standard applies to 70mm 5-perforation film distribution copies. GB/T 9047-1988 Position and dimensions of six-track magnetic soundtrack on 70mm film copies GB/T9047-1988 Standard download decompression password: www.bzxz.net
This standard specifies the width of the six-track magnetic soundtrack on a 70mm 5-perforation film distribution copy, as well as the position and width of the gap between the recording head and the sound reproduction head. This standard applies to 70mm 5-perforation film distribution copies.

National Standard of the People's Republic of China
Position and dimensions of six-track magnetic sound tracks on 70 mm motion-picture relative cassette prints-Locations and dimcnsions
Subject content and scope of application
GB 9047
This standard specifies the position and width dimensions of the six-track magnetic sound track on 70 mm 5-perforation motion picture release prints, as well as the position and width dimensions of the gap between the recording head and the playback head. This standard is applicable to 70 mm 5-perforation motion picture release prints. 2 Position and dimensions
The position and width dimensions of each magnetic stripe and each gap between the magnetic head are as shown in the following figure and table.
Direction of light beam
Six recording heads are connected in a straight line, and the number of each recording head is 1. Or
Six recording heads are connected in a straight line, and the number of each recording head is 4
Direction of film movement
Base pile
Note: The direction of film movement is shown in the figure. The emulsion layer of the film is the light source, and the film layer is facing away from the light source. The Ministry of Radio, Film and Television of the People's Republic of China approved the implementation of 198808.01 on January 21, 1988.
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GE 904788
5. 28± 0. 05
8.38+a.c5
+0. 54±0, 05
1. 27±0. 05
2.92±0. 05
8. 20± 0. 05
59.21±0.05
1. 90 ± 0. 05
64. 50 on 0. 05
67.41±0,05
1. 78+ 0. 03
2) The selection of the gap position and width size of each coated magnetic stripe and each recording head is sufficient to ensure that the film's transverse shrinkage rate is within the range of 0-0.2% during the filming or recording
3) The selection of the position of each playback head of the projector is based on the assumption that the film's transverse shrinkage rate is 0.2% greater during projection than when coated. The gap position of the playback magnetic stripe used in the equipment for producing and distributing copies is the same as the gap position of the recording head. 3 Head gap calibration
The gap of each recording head and the gap of each playback head should be calibrated to a straight line at 90°±5 with the direction of film travel. 4 Recording
Since the audience faces the screen, the magnetic tracks used for recording are connected to the following channels! The first magnetic track is used for the leftmost channel 1
The second magnetic track... is used for the left middle channel
The third magnetic track -
The fourth magnetic track
The fifth magnetic track
For the center channel;
For the right middle channel;
For the rightmost channel:
The sixth magnetic track is used for the ambient sound channel of the auditorium. Note: In special film films, in order to obtain this sound effect, the magnetic tracks on the release team are allowed to be mixed in other ways. 5 Sound and picture frame distance
The magnetic recording on the film lags behind the corresponding picture center by the frame distance,
Note: The sound and picture frames on the film are divided into 24 frames, and the projector is loaded at 25 frames. For the audience F, that is, 15m away from the screen, the sound and picture are synchronized. 6 Reproduction speed
The completed recorded sound track should be reproduced at a speed of 120 perforations per second, that is, 24 frames/s (a frame is 5 perforations), which is approximately equivalent to a linear speed of 34m/min.
Additional notes:
GB 90478
This standard was proposed by the Film Administration of the People's Republic of China on Radio, Film and Television. This standard is under the jurisdiction of the China Electric Science and Technology Research Institute of the Ministry of Radio, Film and Television. The China Film Science and Technology Research Institute of the Ministry of Radio, Film and Television is responsible for drafting and interpreting this standard.
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