US2367293A - Method of preparing control track records - Google Patents

Description

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Jan. 16, 1945. N. LEYINSON 2,367,293

METHOD OF, PREPARING CONTROL TRACK RECORDS Fild June 1, 1942 6 I/J/JU/J/n/A Wan/pm I I m Al THAN Agg ynvsww Y INVENTOR 1/: Of Control Track ORNEY Patented Jan. 16, 1945 PATENT! OFFICE- METHOD OF PREPARING CONTROL TRACK RECORDS Nathan Levlnson, North Hollywood; Calif., as

electrodes of a variable gain amplifier.

signor to Radio Corporation of America Application June 1, 1942, Serial No. 445,308

, 5 Claims.

This invention relatesto sound reproduction and particularly to the production of a control track record for controlling the amplitude of reproduced sound.

In the art of exhibiting motion picture sound film, the reproduction of the'sound portion of the film has been controlled in various manners to enhance the dramatic presentation of the picture. It has been found desirable to increase the volume of reproduction of certainsound sequences such as sounds of earthquakes, fires, avalanches, or the music of large orchestras, choruses, etc. The reproduced amplitude range has heretofore been increased by self-controlled expansion system wherein the variations of the normal amplitude of the sound record control the amplification of the reproducing system. One of between the sprocket holes of the sound or sound and picture film. The sprocket holes produce a carrier current modulated in accordance with the proportion of opaque to transparent area in the lands between the sprocketholes. The light variations'produced by such .a control track are translated into electrical currents which are rectified, filtered and applied to the gain control These derived currents may be used for various purposes one of whichis to control the distribution of sound among several loud speakers and for the relative amplitude of reproduction from dif* ferent speakers as disclosed and claimed in Bier- 'This present invention is directed to an improved method of preparing a control track for any particular sound record which accompanies a motion pictdre, as well as the particular type of control track obtained from the method. In the" past control tracks have been produced by recording them during the reproduction of the sound records, the amplitude or frequency of the control track following the variations of a volume control potentiometer made by an operator as he controlled the amplitude of the reproduced sound. This recording operation was generally done during rerecording and, before the results thereof wirth Patent No. 2,335,575 of November 30, 1943.

could be checked, it was necessary that the control track be developed and printed. If the control track was not correct and required modification, it was generally necessary to record a new control track. After the final control track was obtained, it was printed to the sound track negative after which it was of no further use and was discarded.

The present invention not only provides an improved method whereby the control track isimmediately available for a test check as soon as a determination has been made of the amplitude variations desired, but the control track is. ob-

tained in such a manner that it may be broken down and reused after it has served its purpose, thus eliminating film waste. Although the method of preparing the control record and the record itself is shown in connection with a sprocket hole control track, it is applicable to other forms of control records such as variable frequency control tracks or where the control track is'on a film separate from the sound or picture film. The method, therefore, saves film and time, re- 'gardless of the-.particular form of the .control track itself} In my Patent No.- 2,029,173, of April 28, 1936,- I have disclosed and claimed a sound record which is produced by the intercutting of different. types of sound tracks or records, such as variable area and variable density sound tracks, to produce a wide volume range sound record of liigh quality. The present invention utilizes the general principle of this former invention in that it is directed to a control track which is made up of a plurality of sections of prerecorded or prepared control tracks inter-cut in accordance with cues prepared during a rehearsal. After the control .track has been printed on thesound negative,

the control track film may. be broken down into its sections, which are returned to their respectiveoriginalfilm rolls and used again to make other control records. A specific type of control track record is disclosed and claimed in my copending application, Ser. No. 530,702, filed April 12, 1944.

The principal object of the invention, therefore,-is' to facilitate the production of a particagain for other sound tracks.

A further object 'of the invention is to provide an improved control track for a particular signal track, which control track is available for im-- mediate use in controlling the reproduction or the signal track.

Another object of the invention is to facilitate the construction oi a control track from a plurality of preprepared tracks representing various amplifier gains by inter-cutting said preprepared control tracks to produce a particularcontrol track for a particularsignal track.

Although the novel features which are believed to be characteristic of this invention are'pointed out with particularity in the claims appended hereto, the manner of its organization and the mode of its operation will be better understood by referring to the following description, read in conjunction with the accompanying drawing, in which:

Figs. 1, 2 and 3 are views representing partial sections of films of prerecorded or preprepared control records from which a particular control record is made;

Fig. 4 is a view of a partial section of a film having a particular control track or record there- Fig. 5 is a view or a portion of a composite signal track and control track negative film;

Fig- 6 is a view of a portion of a final composite film bearing pictures, signal track and control track, and

Fig. 7 is a graph showing the variation in am-- plitude obtained from the various width control tracks.

Referring now to Figs. 1,2 and 3, these figures show three prerecorded'control'tracks of the sprocket hole type. That is, Fig. 1 is a print 5 having sprocket holes 6 and a control track 1, the width or the clear portion being of any predetermined width such as 40 mils.- The print shown in Fig. 2 may have a clear portion ll of 20 mils, for instance, while the print M in Fig. 3 may have a clear portion l of 4 mils. Each of these prints may be in rolls .of 1,000 feet or lessand stored in a film library. Although only three prints are shown, there may be many intermediate preprepared prints in which the width'of the clear portions I, l I and I5 may vary in width by approximately 4 mils, 4 mils representing about 1 db variation in volume 01 the reproduced sound.

The relationship between control track width and amplifier gain for a preferred reproducing system is illustrated by the graph ,shown .in Fig.- 7, wherein it is observed that a control track width variation from zero to 40 mils will roduce a change in gain or the amplifier or 10 db, the

plifier and the region from ill to zero mils being used to control another variable gain amplifier. However, as far as the present invention is concerned, it is applicable to control tracks of any and all widths, the tracks being prepared in the same manner, regardless of their manner of use in the reproducing system.

In Fig. 4 is shown a composite control track I! which has been made up of sections of control tracks of different widths. For instance, the left-hand end of the track has a clear portion l8 of 90 mils, in case the reproducing system is designed to use a control track of this width. The next section shows a control track 20 of 40 mils width which may be Fig. 1, followed by a control track section 22 of 20 mils as shown in Fig. 2, then a section 23 of 4 mils as shown in Fig. 3, and then a section 24 of 12 mils, the sections being shown broken from each other to illustrate that they maybe of various lengths depending on the length of the sound sequences of the signal track. This control print is prepar'ed as follows:

The signal track for which the control track is to be prepared is reproduced eitheralone or in conjunction with the projection of the picture which it will accompany. During the reproduction of the signal track, the operator, who is called a mixer, will varythe amplitude of var- 'ious sequences as the sound is reproduced, the

mixer making a record not'only of the amount of variation in the gain, but the point on the signal film at which he made the gain change, this point usually being shown on a film counter within the mixers observation. Thus, as the signal sound track record is reproduced, the mixer varies the gain to increase or decrease the normal volume of the sound in a manner which he considers will enhance the telling of the story, making notes of the amount of thesegain variations and their position on the signal track. These notes now become a cue sheet which is taken to the film library where the various prints such as shown in Figs. 1, 2 and 3'are kept. Now, from these prints various sections of the proper length are cut and spliced together to produce a control record such as shown in Fig. 4. The

signal track is then again reproduced under conwhich he makes note. These new cues are again sent to the library and the control track modified accordingly, which is very quickly accomvariat'ion being linear over substantially the en-- tire range, except as the width of track approaches 40 mils. Thus, substantially 1 db of gain change is obtained by a 4 mil variation in the width of the control track, the pluralityof prints such as shown in Figs. 1-3 being previously prepared-and identified by track width.

In the illustration of these prints in Figs. 1

to 3, the widest width control track is shown as 40 mils, but it is possible to use a track varying up to 90 mils, which corresponds to the usual.

up being used to control one variable gain amplished.

After the control track print is thus prepared, it is sent to the printer where it is used as a mask or a negative for printing the signal track negative such as shown in Fig. 5. That is, a film negative of the sound record to be used for printing release prints is prepared .by recording on this film a signal track which is made upof the various sounds required for the picture. That is, the one sheet and control track may be prepared during the rerecording rehearsals where the sound is produced from a plurality of film records, such as a dialogue track and sound effect tracks, or, after such rerecording has been done. In either case, however, track 28 of film 21 in Fig. 5 is the composite signal track negative used for printing release prints. The control track is printed to negative 21 and will appear as shown at 30 in Fig. 5. The longitudinal spacing of the control and sound tracks along the film may be in the neighborhood of 14 frames (as in an amount depending on the spacing of the respective pick-up elements. This negative 21 is then developed and is used in producing the final composite print '32 as shown in Fig. 6, which-comprises the picture section 33, the si tive control record to said sound record negative film, and simultaneously developing said sound and control records on said negative film.

nal track section 34 and the control track see- I tion 35.- e

After the control track of Fig. 4 has been used as a maskor negative to print the track 30 of Fig. 5, it is then returned to the film library where it is broken down and the various sections returned ,to their respective rolls, according to the width of the tracks I, l l and I5, where they are again available for preparation of other control tracks for difierent soundrecords and pictures. Thus, each control track prepared for any particular picture or sound track is never wasted but may be used over'and over again until it becomes tom or worn out. In this manner no extra film is required for the production of a control.

track after the library has been prepared, while any particular control track is available immediately after preparation of the cue track, thus saving time in checkingeach rehearsal and in obtaining the final control track; It is to be understood that although the invention has been described in connection with preprepared control track rolls varying in width of substantially 4 mils, the width of the tracks on the preprepared rolls may vary in any other manner, depending on the transmission characteristics-of the reproducing equipment. I

said variations, providing a plurality of positive. 7 control records each having a constant amplification control, selecting from said plurality of records, sections corresponding to said cues, assembling said sections to form a separate positive control record for said sound record negative,

- exposing 'a negative mm in accordance with said positive sound record, printingsaid separate posi- '2. The method of producing a composite negative sound and control record for a particular positive sound record having a. plurality of sound sequences comprising cueing said sound record, said cueing including predetermining the desired volume of reproduction of each of said sound sequences, providing a plurality of positive prerecorded control tracks of different levels, selecting control track sections in accordance with said cues from said plurality of prerecorded control tracks, serially assembling said sections to correspond to said positive sound record, re-recording said positive sound record to .a negative film, printing said positive control record to said negative, and simultaneously developing said sound ticular sound record to determine the volume of reproduction of each sequence thereof, assembling from the prerecorded positive control tracks, sections of said tracks corresponding to the length of the sequences to be controlled and the volume at which said sequences are to be reproduced,

7 printing said positive sound record and said positive control track to a negative film, and simultaneously developing said negative sound record and said control track.

The method in accordance with claim 3 in which said assembled sections are broken down which said composite sound and control track negative is printed to a composite positive film of said sound, record, said control track and a concomitant picture.

- NATHAN LEVINSON.

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