Learn more about using noise, voice, music, and diegetic / non-diegetic sound.
One of the most difficult aspects of sound production is noise. Noise is any sound that was unintended and distracts from the purpose of the recording. This can be anything from static interference to really loud music from a passing marching band. If it significantly distracts from the focus sound in the foreground, then it is noise and must be avoided. You can cut down on most noise by making sure that your equipment is up to date and used properly, but also by securing the area and making sure there will not be any significant sound interference.
When recording sound for video you will encounter a variety of different types of sound you will utilize, all of which are unique and must be approached differently, both in production and post-production. Voice is the most common type of sound recording used in video projects, as it is what defines the characters in the video. There are two main types of voice sound that are used in video, dialogue and narration. Dialogue is a conversation between two or more people, while narration is internal and only heard by the audience and/or a limited number of characters. There is the kind of narration that is specifically done by a narrator who is a nonparticipating observer, and follows the rules of literary omniscience or “Voice of God." There is the narration by one of the characters, usually the main character. There is a voice over, where someone narrates the story throughout the film but this narration has no effect on the story and remains more objective. The last kind of voice audio you can utilize is commonly called “voice on tape," and is when one of the subjects in the story talks at the camera as a narrator. This is a little less common than the other three types of narration, mainly because it “breaks the fourth wall." When recording voices the classification of what type it is will be crucial both with the style and equipment you utilize for the production, and how it will be handled in post-production. Dialogue will use regular recording microphones, such as a shotgun or wireless microphone set-up, while narration will almost always be done in some type of recording booth.
Music gives even more character to the video and separates professional video projects from amateur imitations. The most pervasive is story music, which matches the energy and characteristic of the story that is happening in your project. Theme music is one type that many people are familiar with and is usually used during the opening credit to establish the “theme" of the video for the audience. Mood music is used during intense moments of the video to help the audience to have the correct response to the images on the screen. Motif music is used repeatedly in videos as motifs that come up on numerous occasions during the course of a video are correlated with the same music so the audience understands that each of these sequences are supposed to be viewed as the same.
These types of sound differences indicate two different branches of sound that is used in digital video. "Diegetic" sound is sound that actually comes from the space inside the story, like the sound of someone playing tennis while they are actually playing tennis. Even within these sub-classifications there are several branches that indicate the way that this type of sound is utilized. "On-Screen" Diegetic sound originates from something that is actually occurring on the screen, while "Off-Screen" Diegetic sound takes place in the story space but off screen. "External" Diegetic sound is sound that occurs within the story space (Which includes both On-Screen and Off-Screen Diegetic sound), and "Internal" Diegetic is sound that happens in the story space but only internal to a character. This could be things like the internal monologue of a character, which is really happening but only occurs within a characters head. "Non-Diegetic" are sounds from outside the story space. This includes all music whose source is not in the film, some special effects, and narration that comes from someone who is not a character in the story space. It is important to separate these so they do not get confusing when trying to construct a relatable film for an audience.