Seeing may be believing, but hearing can also be essential to great film or video! Especially when it comes to intimate on-screen conversations, interviews, speech, and performance recordings. When your production is dependent on these assets, every recorded word and sound has to be audible and intelligible, otherwise you will be depriving your audience of the full import of your work.
When getting good sound quality is a must, your camera's internal mic, a shotgun mic, or a boom mic may not be good enough or feasible for your production. Internal and shotgun mics are limited by the distance you must maintain from your subject for good visuals, and the farther away the mic, the more open the audio becomes to dilution by any background noise. If you're recording a live music performance or a speech, a boom is just not practical, especially if you're on your own.
Your best bet for a DIY production dependent on good audio is a lavalier (lapel) microphone or a good old-fashioned stick mic. These two types of mics are more precise with direct sound. Lavs, which clip to a lapel, are less visually intrusive for conversational, sit-down interviews, while stick mics are great for man-on-the-street and other types of impromptu audio collection, as lav mics take a little time to set up correctly.
If you make the choice to use a lav or a stick mic, here are a few tips to help maximize your sound quality.
Before you start rolling, take into account the comfort of your interview subject. If the placement or type of microphone makes them uncomfortable, they are more likely to be distracted, and you may not be able to coax as much good information out of them for your piece. Lav mics ideally should be threaded under the subject's clothing (button-down shirts are ideal) from the waste to neck, and the lav should be clipped to the lapel at least 6-8 inches below your subject's mouth. Stick mics should be held or placed at least 6-8 inches away as well. Any closer, and you run the risk of over-modulated sound, and any farther, and you run the risk of picking up too much background noise. Avoid letting the subject hold a stick mic if possible, as they may not hold it at the same angle for the entire shoot.
Always have a set of headphones on hand that you can plug into your camera or audio recorder to listen to the output before recording. Don't be afraid to do a few sound checks and adjust the mic placement more than once, and watch the audio levels on your camera (in the red means too loud!). Have the subject talk out loud for a few minutes and listen for any extraneous background noise. A common mistake with lav mic placement is that it gets caught in the fabric of the subject's top and your sound gets garbled by rustling. For stick mics, make sure the mic is placed so that the pops and clicks of “P's,” “B's” and “T's” don't compromise audio levels. Also, if you are using a wireless lav or stick mic, make sure the frequencies are aligned between the microphone and its wireless receiver, and that the distance between the two is within the device's manufactured range. This prep work will help you achieve the best sound quality without wasting any time or effort.
Using lavs and sticks is rarely an exact science, especially in interview and speech recording situations, where subjects may move around and knock around the mics. Even with the most careful preparation prior to shooting, you should be prepared to face the occasional audio blip or error. Don't get frustrated. Just learn from the experience and use that to help prepare for the next shoot.