The best film sound is already achieved during recording

The best recording results are certainly achieved when a second person controls the sound during the video shoot. Unfortunately, this is often not possible due to a low budget or the equipment used. Then the cut has to be reworked.

As soon as the audio clips have been imported into the editing program's project, the files are first checked for peaks and clipping. All sound levels should remain within a range of approximately -24 to -6 db, speech and dialogue between -9 and -18 db. Often the interview audio is in mono. You should make sure that the audio file is panned into the middle of the stereo image and does not stand alone on the left or right. You should take the time to check the interviews and dialogues and avoid distortions.

To adjust the volume, you can use a compressor plugin that every good editing program provides. The use of a compressor is essential for the voice and prevents the quiet passages, syllables or entire words from being lost in the music. A compressor is a control amplifier whose amplification factor depends on the signal at the input. The term compress comes from the Latin and means: to condense, bundle or pull together.

A compressor has various parameters that can be controlled:
Threshold, Ratio, Attack, Release and Make Up Gain

The threshold control is used to control the level from which the
compressor is working. Below this level is the effect
not active.

With the ratio control you determine how strong the high levels
are to be reduced. The settings are made in
ratio values ​​. For example, 2:1 means that above the
Thresholds are only 1dB at the output when 2dB at the input
were.

With the Attack controller you set the transient phase of the control
fixed, i.e. how fast the compressor reacts to signals.

The release regulates how long the reduction of a
level should stop. If the release is chosen very short,
it may be that the decay of a tone is unnatural
takes course. The release should follow the pace of each other
following impulses.

With the make-up gain, you raise the overall level by the amount
brought about by reducing the loud passages.

After the compressor you can set a limiter plugin to adjust the volume and avoid clipping. With the limiter you set the maximum value for the level to prevent the processed audio signal from getting louder than this. Limiters also have an attack (settling time) in which the signal passes unhindered. With the really expensive devices for studio and broadcast, these tolerances are less than one microsecond. These limiters are called “brickwall limiters”.

Audio adjustments can be made in the project panel or directly in the timeline. Adjust the audio levels of the other tracks as well, always remembering that the more you turn up the volume, the louder the background noise will be. Room noise or background noise, e.g. from computers or air conditioning, is often captured during filming. A more pleasant spatial tone from another scene, which you can copy/paste into the original scene, often helps here.

If this is not possible, you can denoise the sound with a de-noiser plugin. This removes (or reduces) any kind of audible noise in an audio file. One should try when hiring
to find a middle way so that the original sound of the speaking voice is preserved as much as possible. The most important parameters are:

threshold

With this value you determine how high the noise level of the material is and set the threshold so that the noise is eliminated at a quiet spot, for example.

Reduce

This value is used to determine the level to which the noise component should be reduced.

noise type

With this value you determine what kind of noise the material contains: 0 means white noise (even distribution), in positive direction you change the noise type towards blue noise "Hiss"; e.g. tape hiss.