How to Get Great Video Sound from a Moving Subject, Cheap!

lavalier interview micOn a limited budget, how can you get great video sound from a moving subject?  Find out in this CyberKen Blog post.

Film makers who know their stuff will tell you that for story telling, clear sound is more important than clear images.  Mess up the sound and there is no story.  Getting clear sound isn’t too hard indoors with a stationary subject, such as a speaker at a conference:  Just move your tripod close to the speaker, say, within fifteen feet, and use an external mic if you have one.  Test with earphones to make sure the sound is good. If you don’t have an earphones jack on your camera, at least run a test clip and play it back to make sure your mic is recording properly.

But what if your subject is moving around, and outside where there’s wind to contend with?  You could hire a sound man with a boom to hold a mic with a wind screen close to your subject; or you could put a wireless lavalier mic on your subject to transmit the signal to your camera.  Both of those options are costly.

There’s a relatively inexpensive alternative:  Use a lavalier mic made for taking interviews. It will have two mic buds running from the same jack.  Some models are self powered, and some run off the power of a digital recorder.  Wired lavalier mics are often made to plug into a small digital sound recorder with a 3.5 mm jack.  I found that by sewing a small pocket of fake fur around each mic I could prevent rustling sounds from the mics rubbing against clothing.

Another problem with lavalier mics on a mobile subject is keeping the lapel clips from dislodging.  These clips are very small, and often don’t hold well.  Instead, take some gaffers’ tape and tape one mic to the underside of the subject’s right collar, and one to the underside of the left collar.  The mics should be placed approximately at the level of the subject’s collar bone in order to be close enough to the subject’s mouth to pick up clear sound.  My dual lavalier mics are omnidirectional, so they pick up any sound, but the background sounds are quieter than the voice, so the narration is not obscured, and the background sounds give a good context for the scene.

Adjust the recording volume on your digital recorder, start recording a new file, and drop the recorder into your subject’s pocket.  When you are finished filming the scene remove the recorder from your subject’s pocket and press the stop-recording button.

clapper boardNow, how does one synchronize the sound file made with the digital recorder with the visual track of the video clip?  An inexpensive and historic way is to use a clapper board at the beginning of your  clip.  In fact, you don’t even need a clapper board.  You can just film yourself clapping your hands.  In post processing you go to the video frame where the clapping hands or the clapper board segments come together, and you line up the loud clapping mark in the sound track with that frame of the visual track.

An easier but more expensive option is to buy some synchronizing software like PluralEyes.  This software compares the sine waves of the video clips with those of the recorded sound files and after stripping away the sound tracks of the video clips, automatically substitutes the stronger and clearer recorded files, leaving you with video clips with excellent sound.

I found that taping my mics under a collar works really well to eliminate wind rumble.  I’ve tried using wind screens for my shotgun mic (both bought and home made ones), but none have worked as well as mics securely taped under a shirt collar.  Yesterday I ran an experiment.  It was a very windy day.  You can hear the wind, but it sounds like wind should, not as an overpowering rumble.  Click on the right facing arrow below to listen.

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