Dual System Sound for Music Production
Sound Devices regularly receives questions about specific production applications. Below is typical question relating to dual-system sound for music production with a Sound Devices 552:
I need to record audio for a music production. We are using two cameras, and I can't feed the cameras audio. I have to run sound separately. The cameras are Sony EX-1's. They have time code on-board but no time code input or output. How can I sync the audio to the video after? With a clap? Also the cameras are shooting in 29.97DF. So should I load my sound files in to Wave Agent and transpose them to 29.97DF? And for an hour show, if there is no interruption of the cameras and my 552 should everything be in sync at the end? A bit scary...
For long form program like this, it is typical for cameras and audio to be locked to the same sync source. Neither a Sony EX-1 nor a 552 have the ability to receive genlock or word clock, respectively. An hour long take is long for wild sync; if the camera's video generator drifts you may lose lip sync. Because you have two cameras and will presumably be cutting between the two of them, it will make it easier to slip the picture in the edit to work around any drift.
Based on your description, you will shoot this "film style", slating for sync with a clap board. The visual cue of the slate closing and the audible cue of the sound of the slate marks the sync point for each segment. You can either slate the segment at the start or at the end, or both. Both a head slate and a tail slate on a long segment are useful to gauge how much drift occurred during the take. A smart slate, which displays time code, can make it go faster in edit when there are a lot of takes, but smart slates are not necessary when shooting only a few long segments.
As far as frame rate, there isn't going to be an issue. Disregard production time code for sync. Since picture and sound are both in realtime, there is no pull-down and no need to edit the file's sampling rate or time code rate in Wave Agent.