What is double-system recording?

What is double-system recording?

Double-system recording is the process of using two audio recording mediums at the same time for film. On newer professional digital cameras, their audio circuitry has come along way. The primary audio is recorded directly onto the camera with a backup recorder used just in case.

On lower-end video cameras and HDSLR cameras, you must record on a second recording medium to get the best quality audio. Commonly used now are the Portable Digital Recorders or PDR. Besides being a backup or main audio recorder, they work great as a stand-alone recorder for narration, sound effects, or that voice-over your daughter needs for her class project.

When using the double system, whether the camera audio is the main audio or a “scratch track”, you need to sync up the audio. The easiest way is to go back to the old film days (well, not that old) and use a slate between each scene.

How to slate

1. Get both recording mediums going.

2. Put the slate in focus, in front of the camera, call out the scene number, take number and any other information you would like to record (e.g., which channel is the lavaliere microphone and which one is the boom microphone).

3. “Clap” the slate and start shooting. That’s it.

Clap the slate hard enough to be heard by the microphones. In post you will see the clap on the video, hear the clap on the audio tracks and match the two together. Simple.

If you don’t have a slate, a brisk hand-clap will do — just make sure the hands are visible on camera.