Learning Event 3:
USE THE LIMITS OF HEARING IN EDITING
The human ear, when it has not been desensitized by noise or extreme age, is an extremely
sensitive apparatus. Most people can never appreciate how sensitive it is. At its point of greatest
sensitivity, approximately 3,000 cycles per second (cps), it is almost sensitive enough to detect noises
caused by the collision of particles of air as they bump in space. Hearing declines in sensitivity at both
the low and high frequency ends of the audible spectrum, estimated to extend from 15 cps to upward of
When editing recordings made against changing background sounds, make sure that everything
recorded on the tape is heard clearly. An editor tires easily during a long spell of editing and, once he
has become affected by hearing fatigue, it can cause him to make errors he would not have made under
normal conditions. There are two good ways to avoid this fatigue; stop and rest frequently, and adapt
the speaker amplifier to reproduce sound in a particular way.
Learn to recognize the differences between sounds heard at low frequencies. Should both the
loudspeaker and one's hearing be inefficient at low frequencies, as they generally are at low volume, one
will have to strain to hear, or else turn up the volume or sound considerably. Either way, a person will
rapidly become fatigued. When the intensity of sound is raised almost to the point of hurting, the
recognition of pitch changes. To cure this, incorporate into the playback system a low frequency boost.
Highs must be heard clearly at normal volume in order to tell the difference between a "t", "d", or "s" or
similar sounds. This necessitates a slight high boost. Thus, the hearing (if room acoustics are average),
is furnished with sound that is high at both ends and average in the middle.
a. In order to make hearing less fatiguing, there must be compensations for deficiencies in both
hearing and loudspeaking. It is best to have variable control so there can be the exact amount of boost to
prevent hearing fatigue.
b. Remember that this boost is intended for use only in editing--do not employ it for any other
purpose. Remember also that excessive bass boost can induce fatigue as quickly as lack of bass boost.
If the sound balances so that it makes comfortable listening for long periods of time, then it is just right.
Changing noise to music. One useful quirk of hearing has to do with what is heard as noise and
what is heard as musical sound. Sounds that rise gradually and fall away gradually are musical sounds
and are not disturbing. Sounds that begin or end too abruptly disturb hearing and the beginnings and
ending are heard as noise. It takes a definite time, varying with individual perception, of course, in
which to recognize a sound as musical in nature. If the time is too short for recognition to take place,
noise is heard. If the time is much shorter nothing is heard. To apply this observation in tape editing,
use a diagonal cut in splicing tape in order to make sound start and stop gradually. For example, in
splicing tape a speed of 15 ips, a 45-degree