Audio post production is the process of adding, manipulating and processing sound after the production phase has completed. For video content, this will be after there is a “picture lock” – or at least after the first picture lock.. and before the film, TV show or advert is broadcast.
There are many stages of audio post production, most of which can be achieved here in out recording studio and sound mixing room at Wimbledon Studios.
From backgrounds to creature sounds, most of the time the sound captured on the cameras will not be clear enough or of a high enough impact to be used in the final film or show. For animated content, all of the sounds are created from scratch, whereas sometimes we will use some production sounds and then “beef them up” with sounds created in the studio.
Footsteps, clothing movement and other naturally occurring sounds are often added after filming due to the desire for clean, clear dialogue. We will often spend a long time cleaning and clearing up the dialogue tracks, only to re-add movement sounds such as when actors shift positions in chairs or walk across the room. This is especially true for feature films, but becoming more widespread in TV and advertising due to the higher standards of sound afforded by HD transmission.
Compiling good dialogue takes time. Editing dialogue is a process of removing unwanted noises, smoothing over any problems, and ending up with what sounds like a natural recording, even if it has been heavily chopped around. For example – mouth noises. Since microphones are placed unnaturally close to actors mouths, we will often find a lot of little pops and clicks from the actors’ saliva are heard on recordings, especially on close mic’d and quiet dialogue pieces. We don’t hear these in real life because we’re farther away, but the microphone does, so we use an array of tools, from simple crossfading to de-clicking plugins to return the dialogue to a natural sounding state.
We record voiceover in our vocal booth for narrative pieces such as documentaries, character voices for animated films and adverts, as well as the voiceover for adverts and online video content. We have a number of voice artists available to help with your project, or can direct your voice actor(s) to capture the perfect voice performance. The vocal booth is equipped with an HD video monitor so voice cues can be recorded to picture. We find that capturing the voiceover helps the editing process, so will often record the VO before the video is cut, although this does depend on the target product.
Automatic Dialogue Replacement, or Additional Dialogue Recording will be used whenever the original dialogue is not useable for reasons of noise, or often to add lines of dialogue to help with the narrative. ADR is invariably best recorded on-location in the original scene, and a good sound recordist will identify any issues and get alternate dialogue recorded on the day, but this is not always possible. If lines need to be re-recorded, which is often the case in action scenes or scenes in noisy environments then an ADR session will be arranged where the actors come into the studio and repeat their lines at the right speed and with the correct emotion of the original – mimicking their original performance as closely as possible. The additional dialogue will then be mixed with backgrounds, hopefully from the original scene, and a bit of reverb to make it sound as if it was recorded at the time.
Often the piece of music required for a project will be the wrong length, or we only want certain sections of the music. In this case we will edit the music to fit, ensuring that we maintain musical integrity throughout. There’s nothing worse than hearing a badly cut piece of music where you can hear the join. Rather than crossfading, we will often use 2 tracks for editing a single piece of music so that the sections can be lined up with the waveform peaks matching the beats to ensure a smooth and inaudible transition as we edit from one section of a track to the next.
Track-laying is the process of laying out the tracks of sound on the timeline (in ProTools in our case). This can range in complexity from simple track-laying such as short commercials where the counds are supplied ready-mixed and we simply add voiceover and mix, to more complicated projects with multiple dialogue tracks, foley, backgrounds, sound effects and music. This is the stage of audio post production that happens before the sound mixing can begin. Sounds will be “spotted” to picture in the correct locations so that they play back with what is happening on-screen.
Once the track laying has taken place, there will be some preparations made for mixing. A lot of the clips of sound will be adjusted so that they are the same or consistent volume, some basic EQ and compression will be applied and the ProTools session will be marked up with important markers, tracks grouped by colours and groups of tracks (dialogues, production effects etc) routed to buses so that the entire dialogue level can be controlled from a single fader.
Once the session is prepared, the dubbing mixer will start to mix the content. If the track-laying is good, then this will be an easier process – the track-lay will often arrange the audio clips so that, for instance, shots with the same problems of “rumble” will be placed on the same track, so the dubbing mixer can apply an EQ to that track to remove the low rumble, and effect every clip that has the problem. Further EQ, compression, panning and levelling will be done at this stage to ensure that there is a clear consistent sound for the whole piece, whether it’s a 45 minute documentary or 10 second advert.
With most projects, we will mix as we go along, and target the correct broadcast levels. Over the past few years, you will have noticed that the “everything turned up to 11” nature of most adverts has been gradually calming down. This is due to new regulations that have spread across Europe, the US, Canada, Australia, Japan and the rest of the world governing how loud any programme is allowed to be. Rather than the old mechanism of setting a maximum level, with advertisers abusing that level using compression to achieve a much higher perceived loudness than the surrounding programmes. We not only balance and mix audio, but ensure it complies with the broadcast regulations for whatever territory it is to be broadcast, and also achieve a nice even level for online.