In most cases, the sound designer gets involved in an audiovisual project when the recording has already been made. But in some cases the work starts at the same time with script in hand. In this way we can perform the task of pre-production selection of key sounds that may be of importance in the development of the script.
Normally in a post-production project we will have 5 well-defined layers (layers), Objects, Environments, Voices, Transitions and Music. The first step when developing a post-production project will be the definition of the "map", in which by means of markers we will note the start and end of each segment of the sequence.
It will be the video edition that will determine the dynamics of the work.
During the first stage we will concentrate on cleaning the dialog channel, we will eliminate noise and interference, in some cases we will be able to reuse the effects of the environment. But normally this work is done artificially with foley techniques, for example.
By means of an equalization, compression and premix we make sure that all the dialogs of the sequence are correctly leveled.
For this stage we already have clear the atmosphere of each scene, we can use sound libraries, foley techniques or even tracks that have been collected at the time of filming.
In the same way, the definition of concrete and support sounds form 60% of the work.
The composition of original music against image will be a task that can be done in parallel, but it is important that there is collaboration between the designer and the musician.
This is just part of the job, we will not forget that the final mix and the mastering of the piece is very important.