Sound Advice: Outdoor Audio

Sound Advice: Outdoor Audio

Learning to deal with the elements as you shoot video.

Ah, the great outdoors. It's a video shooter's dream come true. Loads of free lighting, gorgeous backgrounds and breathtaking scenery - what more could you want? At least visually, shooting outdoors is a wonderful idea. For audio, however, an outdoor shoot presents a new set of challenges. Learning to deal with these challenges is a combination of the right tools and a knowledge of all the variables. Grab your walking stick and camcorder and join us on a hike through the backwoods of outdoor audio.

It's Not Nice to Fool Mother Nature
If you plan to shoot outdoors, rest assured you'll have to deal with less than ideal weather conditions from time to time. Of particular concern are the detrimental effects of rain and snow on your precious (i.e. expensive) audio and video equipment. Wet weather and electronic gear mix like oil and water, so you'll do well to prepare for the worst.

First, and most important, is to keep the water out of your camera. Surely you've seen the advertisements in the back of Videomaker for rain slickers made specifically for cameras. These are excellent accessories for those who shoot outdoors on a regular basis. The occasional outdoor videographer, however, can make due with a simple plastic trash bag. Cut a hole for your lens in one corner of the bag and a hole for the viewfinder in the other corner. You'll still have easy access to the controls from underneath, although it will be difficult to use a flip-out LCD and certain viewfinders. It's not as waterproof as the rain capes with watertight lens holes, but a trash bag might be sufficient in a light mist.

Zipper sandwich bags come in handy with your audio equipment. A wireless microphone transmitter pack doesn't like the wetness any more than your camera, so keep it dry too. You'll need a knife and some gaffer's tape to complete the task, but the finished project will keep your transmitter dry and away from the repair bench. Wired microphones fare better in the elements, but it's still a good idea to keep the connectors dry with a simple wrap of electrical tape. The same applies for battery doors.

Exposed microphones - whether handheld, shotgun or lapel - are more of a sticking point. It's never a good idea to get a microphone wet, regardless of type or application. For a quick outdoor shoot, a simple foam windscreen will keep the microphone dry enough, but extended shoots require measures that are more drastic. While you can cover your microphone with the same bag as your camera, the audio will suffer. Not only will you hear the drops of rain falling on the plastic, the covering will dramatically change the quality of the sound. Honestly, there isn't a simple fix for this problem. There are professional windscreens that make notable improvements, but the price may be out of reach for many casual shooters. If you're using a lapel microphone, it's possible to secure the element under your talent's clothing or even under the brim of a hat. These are extreme measures and will negatively affect the sound quality, but it's a reasonable tradeoff if the alternative is to abort the shoot.

Although not specifically audio related, it's a good idea to avoid rapid shifts in temperature and humidity - your audio and video gear won't like these changes and may rebel. Condensation (when moving from cold to warm environs) will produce everything from random glitches to a complete shutdown to fried circuitry. You can minimize these effects with two simple techniques. First, place several packs of silica gel in your camera case to absorb excess humidity. Second, when moving from a cool environment to a warm one, give the equipment several minutes to acclimate. You'll eliminate the embarrassment of an equipment failure and save wear-and-tear on your gear too.

The Windscreen is Your Friend
Whether you shoot in wetness or not, every outdoor shooter has to deal with wind noise. Uncontrolled, wind noise can render your audio useless and there is no way to repair the damage in post-production. Regardless of the audio you capture outside, your microphone needs a windscreen.

The most common type of windscreen is made from open-cell urethane foam. Although available as an accessory for virtually every type of microphone, some microphones come with the windscreen permanently installed. The windscreen's task is simple - keep the wind out of the microphone. Foam windscreens vary in their ability to accomplish this mission, but they're inexpensive, readily available and work well in many situations.

In more extreme conditions, you'll need a professional windscreen - often called a windsock or zeppelin. These windscreens differ in size and construction, but most often use a special cloth stretched over an open frame. The microphone is enclosed inside the frame and the cloth blocks the wind from entering. The completed assembly looks something like a blimp, hence the zeppelin reference. The windsock is effective at eliminating wind noise, but costs a good deal more than the common foam windscreen. In addition, the length and diameter of your microphone factor into the design of the enclosure. For shooters in brutal wind conditions, the addition of a fuzzy fur cover to the windsock can eliminate the detrimental effects of wind noise up to 60 miles per hour.

Dealing With Background Noise
Whether outdoors means mountain streams or traffic jams, you have to deal with unwanted noises in your audio. These may manifest themselves as simple, random interruptions or as a constant roar that all but obscures the sound you want to record. In any case, there are weapons at your disposal to minimize these effects.

The simplest technique is to use natural barriers to block the noise. If you're shooting a subject using a handheld or lapel microphone, position him with his back to the noise. His body will block a great deal of noise and can make an impractical setup feasible. You can exploit other barriers such as buildings, rocks and trees to similar effect. When using a directional shotgun microphone, utilize the built-in null points to your advantage. You can leverage this knowledge of pickup patterns by placing the microphone where it will pick up the maximum amount of sound you want and a minimum of the sound you don't.

On the other hand, you are shooting outdoors and your viewers associate certain ambient sounds, such as birds chirping or insects humming, with being outside. If the area you're featuring contains colorful audio, capture several minutes of sound on tape after the shoot. Back in post-production, you'll have a way to cover abrupt edits and scenic shots that don't have acceptable audio. Properly blended, these patches will sound perfectly natural, plus you'll have another soundscape for your audio effects library. It is better to have the option to add ambient noise back into the mix in post than to try and remove it.

Shooting in the great outdoors can be challenging, but some preparation and practice will have you ready to tackle those projects, and you'll have some impressive audio to show for your efforts.

[Sidebar: DIY Windsock]
Professional microphone zeppelins or windsocks can cost several hundred dollars and aren't worth the cost for casual use. A few dollars and a trip to the fabric store will supply most of what you need to build a simple windsock. First, pick up a small roll of fiber batting - the type used to fill quilts and blankets. Next, buy some costume fur with a nap of one inch or longer. Installation is simple. First, wrap some batting around your microphone, securing it with rubber bands. Then, do the same with the fur if you're shooting in strong winds. This setup will likely thin out the sound, but wind noise won't be as much of an issue.

[Sidebar: Listen Closely]
Most shooters know to monitor their audio with a pair of headphones, but monitoring outdoors adds some complexity. Many camcorders offer skimpy headphone amplifiers, so you have to make the most of every milliwatt. Start with a pair of sealed-cup (circumaural) headphones. These will block outside sounds and allow you to concentrate on what's coming through the microphone. Several manufacturers offer excellent sealed-cup models, but try them with your camcorder before buying if possible. As you sample several brands, you'll discover that some headphones play much louder than others. Find the best tradeoff of sound quality versus volume and you'll have an audio reference that will serve you well in every circumstance.

Issue: 

Hal
Robertson
Tue, 04/01/2003 - 12:00am