Sound sync method — boom or AD records take number and scene verbally before rolling. Critical for editorial and sound department.
The boom operator or assistant director speaks the take number, scene, and other relevant data directly into the microphone before each shot — this is the voice slate, also called a sound slate. It runs immediately before "camera roll," after the clapperboard (visual) has been lowered. The goal: to create an acoustic marker that is indispensable in editing and synchronization.
On set, it works like this: the sound mixer or their assistant holds the microphone ready, clearly speaking the scene number, take number, and often the date and other details — such as camera setup or notes on performance issues from the previous take. This information is recorded directly onto the audio recorder and later synchronized with the camera image. In editing, the voice slate serves as an acoustic anchor point: the editor can use it to precisely match the audio track with the image, especially if the camera and sound equipment ran asynchronously (e.g., in multi-camera setups or with RED cameras, which can store different frame rates internally). During synchronized shooting (dialogue, lip-sync), the voice slate is critical — without it, sync errors quickly arise in editing or color grading.
Craftsmanship and communication merge here: the voice slate must be clear, precise, and consistently structured. A good sound assistant always speaks in the same order — scene, take, then additions. This allows the editor to work without thinking later. Some teams also use sound slates with automatic timecode readers that burn in digital data directly; nevertheless, the verbal voice slate is standard and often legally required, for example, for broadcast or studio productions.
The practical benefit extends beyond pure synchronization: during the post-production process, the voice slate allows the sound designer and editor to quickly orient themselves in chaotic recording sessions. For pickups or reshoots weeks later, the sound supervisor can immediately reconstruct which take was actually used. And in the mixing theater, it helps the re-recording mixer quickly identify problems in individual takes. So, it's not just administration — it's an efficiency tool for the entire post-production pipeline.