An external mic can help significantly.
Inexpensive, compact video cameras can make for great-looking home videos with minimal equipment. However, relying on your camera’s integrated microphone may result in audio that sounds like you’re mumbling inside a cave or wind noise that completely obscures your dialogue. If the sound quality of your home videos is as important to you as the image quality, a little planning and some outboard equipment can work wonders.
When you can’t go back and do a re-take, however, the problem is more difficult to solve. Although even an experienced audio producer might not make tinny or muffled audio sound clean and clear, with some patience and the right tools you may at least be able to salvage your footage.
1. Connect an external microphone if your camera offers a mic input. The type of microphone to use will depend on your shooting environment: a lavalier mic clipped to a tie, collar or lapel will best capture the voice of a single subject, while a “shotgun” mic placed out of frame or on the camera itself will work best for multiple speakers or spontaneous outdoor shooting. For the best results, place a microphone as close to your subject as possible.
If your camera doesn’t allow you to connect an external microphone, consider using a separate device, such as a digital audio recorder or a laptop, to record your audio. Then sync your audio recording with the video in your editing application.
2. Improve the acoustics of the space in which you’re shooting. Bare, hard walls will reflect sound, creating echoes and adding harshness to the sound. For best results, shoot your video in a carpeted, furnished room with bookshelves and other items to absorb sound or disrupt reflections and don’t allow your subjects to stand against bare walls.
3. Check your audio levels and sound quality before you begin by shooting a short piece of video and listening to it carefully. If the sound quality is poor or background noise is overwhelming, use a different microphone or move your subjects to a more acoustically suitable location. If wind noise is a problem, use a windscreen on your microphone, create a shield with cardboard or simply turn the mic until the wind isn’t audible.
4. Open your movie in a video editing application with audio controls, such as Apple iMovie or Final Cut, Sony Vegas or Adobe Premiere. If you’re more comfortable working with an audio application such as Audacity or WavePad, you can detach the audio in your video editing application, edit it in your audio app and re-import it to the video app.
5. Filter out hiss, boom or hum using either manual equalization or the application’s audio filters. For example, you can reduce wind noise using a “high pass” filter that reduces low frequencies. To reduce hiss, use a “low pass” filter. Electronic hum usually appears at 60 hertz, so reduce that frequency to remove it. For more difficult problems like loud background noise and harsh tones, you may need to experiment with EQ.
6. To raise a consistently low sound level, use either the application’s manual audio level control or its normalization filter. To smooth out inconsistent sound levels, use a compressor/limiter filter.