How to add sound to amateur films (1954)

Split -Track Mixing Instead of partly erasing the whole width of the music recording as in twin-track mixing, you can completely erase part of the width. What is left is then just as good as before, but gives a lower volume on playback. On the part-width of track which you have erased, you can record the commentary. If you make a slip, you can erase the commentary and replace it without affecting the recording of music. This system requires no electrical alterations. But since it is operated mechanically, it is more readily applicable to some recorders than others, depending on their mechanical design. First of all record all the music. Do this at the level required for the passages without commentary. Even where the commentary is to be added, do not fade down the music. After that, play through the tape until you reach the point at which you are going to add a passage of commentary. Stop the recorder here and displace the tape (or the two heads) sideways by one-half of a normal track width. On a single track recorder, shift the tape (or heads) by J inch up or down. On a twin-track machine, the displacement must be only Y0 inch. No elaborate equipment is needed with the split-track method of mixing commentary and music. Music is recorded (top left) in the usual way. Later (top right) the tape is partially displaced so that half the recording may be erased and replaced by commentary. By gradual movement in and out of the displaced position, the recording of music is faded down before the commentary (bottom) and up again at the end. Erase -1 r Music Erase i . Commentary " SW^'^N^ \ Normal Potion of { _^^^^^ssj^^^^g Music Recorded Music Recorded Music Erased Commentary Recorded Music Returns to Onq.nal Volume Ccmmenrar? Added Music Fadei Down to Music JS^SS^^I^^^^^gg 5 85