Sync Sound

Sync Sound refers to process where sound for a film or documentary is recorded simultaneously to the visuals. For instance, dialogue between two characters may be recorded by an overhanging boom mic slightly out of shot, which will later be synchronised up with the shots taken in post-production. While most cameras come equipped with microphones, it is often the case that these microphones do not record at particularly high quality. Using them is often also not practical given their relationship with camera position. As a result, filmmakers often record sound separately using boom mics. These allow the microphone to be as held as close as possible to the sound being recorded without disrupting the shot. Furthermore, as a result of the microphone being directional, sound is only pick up from directly in front of the mic, meaning that it allows for clear, crisp recordings with only minimal unwanted noise; if any.

There are also certain microphones that are more useful in certain situations than others due to their direction (where the microphone can and can't pick up sound).

Omnidirectional Microphones: Microphones that record sound equally in a 360 degree radius of the microphone. They are equally sensitive in all directions, so can therefore be useful if the filmmaker intends to record the overall sound of an area, or people speaking from multiple directions.

 



Cardioid Microphones: Microphones that are sensitive to sound from the front and rear, and can record good quality sound in these directions. However, they record sound poorly from behind. These are the most commonly used type of microphone as they allow for sounds to picked up clearly from whatever the mic is pointing at, while also rejecting unwanted sounds from behind the mic.


 


Directional Microphones (Rifle/Shotgun): As the name suggests, this is a particularly directionally sensitive microphone. It provides a very selective recording of sound, making it ideal for precise recordings in noisy environments. It has narrow but sensitive recording at its front, some additional pickup at its sides, and a small level of sensitivity at its rear.


The clap from clapper boards is used to create a distinct spike on the waveform of a scene's recorded sound. This is used to act as a marker that allows synchronisation of sound and images to be done much more easily. It is also common practice to make two recordings at different bit-rates, such as making one recording at -12db, and another at -18db. This allows for the maximum amount of usable sound as it allows the filmmaker to avoid having to dispose of sound due to overloading.