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Audio issues while making firearms videos

Home Forums Technique Sound Audio issues while making firearms videos

This topic contains 1 reply, has 3 voices, and was last updated by  matt8090 7 months, 4 weeks ago.

  • Author
    Posts
  • #88935

    matt8090
    Member

    I’m making firearm review videos for my YouTube channel. I’ve been using a lavalier mic plugged directly into my camera and that works quite well. However, I’d rather not be tethered to my camera and tripod at times. My camera is a Canon Vixia HF R400. I recently got a Rode Videomic Pro to use. I absolutely love the sound quality in most circumstances but in scenes when I’m shooting a gun the sound level will drop waaaay down. It won’t come back up to normal levels until after the shooting stops and I’ve been talking again for about 4-5 seconds. I’ve got the power on the middle slot, not on the high pass filter, and bottom switch on -10 dB. I hope I’ve explained the problem well enough. If need be I can post a sample video of what’s going on. Any help would be greatly appreciated guys!

  • #213208

    matt8090
    Member

    I decided to go ahead and upload a snip of a video that will show what’s happening. As you can see, after the first couple shots the audio drops way down and doesn’t come back up until about 5-6 seconds after I start talking.

  • #213210

    JackWolcott
    Participant

    MY guess would be that the automatic gain control is suppressing the gain to compensate for the loudness of the gun shots. If possible, turn off the auto gain in the audio system, then set the gain on the camera to -40 to -60db while you’re shooting and back up to -12db when you’re talking. When taping musical events we’ve found that rim-shots on the drum will have the same effect that you’re encountering if we have the audio set to “auto.” As a matter of good practice when taping, for better control it’s best to have the audio in the manual mode at all times.
    Another approach would be to kill the live gunshot audio entirely, record the shots in isolation at an appropriate level and add them to the project in post. This would give you the greatest control.

  • #213237

    paulears
    Participant

    Auto gain is the bodge to not having a sound operator. It’s a reactive blunt tool. A limiter is better for just controlling the maximum level, but gunshots are a tricky thing to record. To do it properly really takes two channels – one probably with a pad, and much lower level to capture the transients of the gunshot without distortion – which can come from the mic itself if it’s a condenser without a pad, or the preamp. Your other channel records the ambient sound properly and will inevitably flat-top when the shot happens. In post, you fix it using both channels. AGC always has a gentle restore so you don’t usually hear it working, but the gunshot drives the level down so far, the long recovery is normal. Shortening it, even if it’s an option just produces a weird pumping sound as it opens and closes the gain. There is no simple solution – the dynamic range is just far too wide.

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