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Great question, Jesse – and great response, @-PT!
Is the iphone the only camera position, or is this a multi-cam setup?
For me, I’d keep this pretty simple:
- Ensure the clap audio in your close mics lines up with the clap motion in the video. NOTE: mute or disregard the iphone audio at this point! Move the iphone video (with its muted audio) around, frame by frame, until it syncs up nicely with your close-mic audio tracks.
- Now, unlink the iphone audio from the iphone video so you can move the iphone audio independently from its video track.
- Next, move the unlinked iphone audio so that it’s “clap” syncs up with your close mic claps. NOTE: sometimes I’ll change my vid editor timeline to Samples at this point if I’m unable to achieve good sync/phase using the Frames timeline.
- Unmute the stereo iphone audio track and balance against your direct mics to taste!
Bonus Round: Add a millisecond-based delay plugin to your iphone audio set to 100% Wet, and try sweeping around the delay time (say, btwn 0 and 100ms) to simulate control over how far away the iphone microphone is. By adding 15 milliseconds, the iphone mic will sound as if it’s roughly 15 feet away from your direct mics! (Yay, the science part!). NOTE: honestly, for mixing purposes, at this point I would just ditch the science and use my ears while sweeping around the ms delay time on the plugin until I settle on something that sounds cool… who knows– it might sound amazing set to 1137ms!)
Can’t wait to hear what you end up with!
🤓
PS – here’s some speed of sound info from the ol’ Google machine:
It would take approximately 13.3 milliseconds for sound to travel 15 feet in dry air at room temperature.
The calculation is based on the following:- Speed of sound: Approximately 1,125 feet per second (fps) at 20 °C (68 °F).
- Formula: Time = Distance / Speed
- Calculation in seconds: 15 feet / 1,125 fps = 0.01333 seconds.
- Convert to milliseconds (1 second = 1,000 milliseconds): 0.01333 seconds * 1,000 ms/second ≈ 13.3 ms.
A common approximation used in live sound engineering is that sound travels about one foot per millisecond (1 ms/ft). Using this simple rule of thumb, the time would be approximately 15 milliseconds. The more precise calculation above gives a more accurate value.