Here are a few tips for doing sound mixing on a dialogue scene for video.
How to Edit a Dialogue Scene
Dialogue is often the fundamental aspect of narrative and documentary films as the words spoken between characters carry the story along. This can also be the most difficult part of production as dialogue is hard to capture in the real world. Background sounds, microphone difficulty, and even actor problems can all interfere with giving you the clean dialogue that you need to figure out how to edit a dialogue scene for the audio. Once you have gone through and picked out your best scenes, edited together the dialogue scene for the picture, and made sure that it looks the way you want in terms of the conventional cuts, you then can send it over to the sound mixer. Here are a few tips for sound mixing dialogue projects when learning how to edit a dialogue scene.
Make it Last
The most important thing you need to remember when you are sound mixing dialogue is that the dialogue scene should be in its final version before it gets to the audio mixer. The dialogue editing should already be complete as stated by the director and editor as they have chosen it for performance, continuity, and visuals. This can often be difficult if what comes to the audio mixer for dialogue editing sound could be unusable or irreparable, but this is usually going to be the responsibility of the sound mixer anyway. The reason here is that the dialogue editing in the non-linear video editing program is going to be composed of many fragments of audio, but after the audio mix is complete it will come back over as a single one. This means that adding cuts, overlapping layers, and basically doing any rearranging in the edit will be very difficult. Make the audio mix the last thing you do, and you can do it at the same time as the color grade.
Working on the levels of the audio is going to be one of the most important parts of sound mixing dialogue. All audio tracks sound different as they are all recorded in slightly different situations, and therefore they have to be made to match. You want each cut in a dialogue editing situation to sound similar so that they feel natural for the location. You can have some sounds come above and below the rest of the consistency, but these are intended to stand out. You also want to keep your audio levels at no higher than -6db to -3db, otherwise the peaks will blow out and distort.
For dialogue, you have to make the sound of the voices reflect the area that they are supposed to be in for the story space. You almost never actually film in the place that you are portraying, so you may have to do audio effects on the dialogue itself. The TL Space, a feature that is common in audio mixing software like Pro Tools, will put an effect onto a voice based on a type of location that you can see visually. Other than this, you can simply add EQ and reverb until you get the type of echo you want for a location. Again, consistency between shots is going to be the most important aspect.
The background noise is almost always going to be a problem unless you were recording in pure silence. If you want to try to take the background noise out, it will have to be a consistent sound and you can set a noise print, or begin working with the EQ and different filters such as the high pass filter to try and isolate and eliminate certain tones. This is only half the battle because you will need to also lay over the room tone that you recorded for that area so you can try and set a consistent background sound for the area between clips. Every area in the world has a tone to it, and if that is missing altogether you will have a more difficult time than if it is too present.
Source: Author's own experience.