The Power of Sound
When I was little, my parents owned a tiny movie theater in a small town in Montana. While my dad projected the film, my mom sold tickets and refreshments. Meanwhile, I watched what movies I wanted–especially the scary ones.
At the scariest points, I would cover my eyes. When the film scared me enough, I would run to my mom, who taught me a lesson she learned from her own father, a musical composer and arranger for Hollywood films. "Cover your ears, not your eyes," she told me.
And I found she was right. It was the sound that created the tension and the fear. I could watch even the scariest movies without the sound. I learned early the importance of sound in creating the proper atmosphere for a movie.
Ive since come to believe that sound is responsible for 50% and often more than 50% of the full effect of motion pictures. Yet all too many videomakers record notoriously bad audio. Its one area where almost every videomaker needs improvement.
Every camcorder owner whos serious about the craft should try to learn at least the basics of the science of acoustics. A good start is the article "Acoustic Bounce" (Videomaker, Sept. 1993). Another way is to watch and learn from professional videos; spend some time listening as well as looking when you watch a rented video.
For the purposes of this article, I took a different approach. I located an accomplished audio-for-video specialist and asked him a number of questions that I thought videomakers would ask in their quest for better camcorder audio. What follows is a brief account of the high points of that interview, interspersed with comments and pointers from my own experiences. In reading this, youll gain a better understanding of how to get good audio when youre shooting on location.
Getting Packed and Ready
Richard Kuschel is an audio specialist. His audio-for-video background runs the gamut from high-school band concerts to national broadcast television. Currently, hes an audio/location consultant for outdoor programs on both ESPN and TNN. He also instructs college television and journalism students in the basics of audio for broadcast.
I interviewed Kuschel as he prepared to go on location to record the grand finale concert of the All-state High School Music Festival. That particular shoot sounded simple enough to me, but Kuschel corrected me on that point. "I’m going to be recording an evening where audio levels will be all over the place. I’ll have to be able to capture a band blasting at full volume, and minutes later record a quiet vocal soloist from the choir. All of the challenging elements of location audio are here: tough levels, tough acoustics and mixing formats–recording a DAT audio tape while simultaneously feeding audio to two videomakers."
Many video pros consult Kuschel for advice on audio-for-video problems. He has found that lack of advance planning and testing is the single biggest problem that most videomakers encounter. Also, many novice videomakers start with the attitude that audio is somehow simpler and easier to deal with than video.
"Time after time, I meet videomakers who have lost entire shoots, much to the anger and disappointment of their paying customers, because they failed to master basic audio. Without good audio, all you have are pretty pictures; youre missing what is often more than 50% of what is happening on the screen."
Whenever possible, Kuschel visits the location before the shoot. "When the theater is packed with 1500 people," he says, "its a pretty poor time to be looking for electric outlets, running cable and testing connections."
Once Kuschel has visited the location, he prepares for the shoot. To make this phase of the production easier, he has all of his pieces of gear clearly labeled, from the longest cables to the tiniest adapters. If he knows the upcoming shoot will require a microphone with a 100-foot cable ending in a mini-stereo plug to go into a camcorder, he actually hooks it up and tries it out beforehand.
The next stage of the process is packing the equipment for transport. When he leaves for a shoot, Kuschel can fit all the gear he needs into a small duffel bag. Cables go on the bottom, mikes (preferably in their boxes or cases) in the middle, and his assortment of connectors/adapters on top. Before they get packed into the bag, connectors and adapters go into a small fishing tackle box with a transparent lid and built-in compartments.
When it comes time to put together your own audio kit, take a tip from Kuschel: dont just throw everything into a container haphazardly. No matter how you try, there will be times when you cant visit a location ahead of time, so this bag has to contain all your options and be able to get you up and running in almost any circumstance. Be sure to have a duplicate or a work-around for every item that is truly essential.
Many videomakers spend most of their lives never looking beyond the internal mike on their camcorder. But unless they get into external mikes, their audio will be mediocre at best on all their productions.
Many camera operators are very reluctant to leave the security of their on-camera mikes; but once they experience the results of external miking, a new universe will open up to them. Often, the best location for a mike is near or even on the audio subject, while the camera (and the on-camera mike) must be farther away from the scene.
Kuschel warns that videomakers should make the leap to external mikes with caution. "As soon as a videomaker goes external with the audio, the complexity level goes up dramatically, and so does the chance of breakdown and failure. Youre not likely to have a broken cable or a dead connector on your in-camera mike, as you well might on an external one."
As stated before, the best way to get around this problem is to thoroughly test all of your connections before you arrive at the location of the shoot. That way, youll be certain that all cables and connectors are working properly.
On location, Kuschel usually sets up by starting at the audio source and working back to the camcorder. Mike selection usually comes first. "You can do 95% of your external miking with either a lavalier mike or a high-quality condenser mike with a cardioid (uni-directional) pattern. Much of the audio work I encounter involves taping just one person. To do this, I clip the lav mike onto the talents tie or shirt about 5 or 6 inches below the chin and run the wire through the shirt or under the coat so it’s invisible to the camera. I always make sure to place the mike so that moving clothing or body parts wont brush against it and create unwanted noise."
Kuschel continues: "For groups of people or large-scale events, I place the condenser mike on a stand at an appropriate distance. The further the mike is from the talent, the more room sound or ambience youll record. There are times when you want some ambient sound, such as the audience applause during a concert–but at such times, you lose some of the quality obtained with close-miking your source. Strive for a good balance; but when in doubt, place the mike closer." (For more on mikes and mike patterns, see "The Great Outdoors" in the January 1995 issue of Videomaker).
Sometimes you can obtain the best sound by wiring your camera to a house feed–a mixing board thats already providing sound to the audience. The location may have an excellent mike setup with high-quality equipment you could never duplicate. It makes sense to take advantage of this feed when its appropriate. But its critical to understand the connection problems and level matching that you can encounter when taking a feed from a mixer.
Once youve placed the mike or tapped into the house feed, the signal has to get to the camera, usually through cables. After you have run your cable, tape it down in critical places. You can’t afford to lose your audio signal because someone tripped on a loose cable.
The mike jacks on most camcorders receive 1/8-inch stereo mini-plugs, but many mixing boards and microphone setups use other connections. A good selection of audio adapters is a must. The basic connectors you will encounter are XLR, 1/4-inch phone plugs, 1/8-inch mini-plugs and submini-plugs. You must be at least acquainted with these configurations and able to convert them into the appropriate input for your camcorder (most of which accept an 1/8-inch mini-plug). For an overview of all the possible combinations, go to a local Radio Shack and look at the numerous adapters.
When hooking up your audio, its important to pay close attention to the various signal levels involved. It may help to think of the different levels in terms of size: a mike-level signal is small in strength, a line-level signal is medium strength and an amplified signal (such as a speaker output) is large. If you plug a large or medium signal into an input meant for a small signal, you can distort your audio or even damage your equipment.
Making signal levels compatible with your equipment usually happens just before you plug the signal into the camcorder. According to Kuschel: "The biggest single problem comes in matching line levels to mike levels. Most mixers put out a line-level signal, which must be attenuated or reduced by about 40dB to make it compatible with the camcorder’s mike-level inputs." Kuschel’s comments on level-matching back up my own experience. Videomakers can purchase a "direct box" for this purpose, but the most common method of reducing line-level signals is with a small in-line "pad."
Radio Shack sells a small red 40dB pad that has been a long-time staple for many videomakers. It receives an RCA-style line-level signal on one end and outputs a mike-level 1/8-inch mini-plug on the other. If your camcorder requires a stereo signal, a mono-mini to stereo-mini adapter can send the signal to both tracks, though the signal will still be mono.
As soon as you begin to stack adapters to make the right connection, the weight of the assembly increases. Kuschel recommends custom-built cords that move the multiple pads, jacks and plugs away from the input jack on the camcorder. "One videomaker I worked with had about 4 adapters chained together and plugged directly into his camcorder. Halfway through the shoot, he accidentally stepped on his own cable. This didn’t just pull the assembly out of the camera; it actually broke the camcorder mike input. He was in for an expensive repair."
To avoid this kind of situation, have a 4-foot cable made with the appropriate mono or stereo plug on the camcorder end. On the other end, use the connector most appropriate for your purposes. You can then do your adapting away from the cameras delicate mike jack. For added stability, use a strong cable-tie to secure the 4-foot cable to a leg of your tripod.
Once you have placed your camera, chosen your audio source and tested the connection of the two, youre ready to shoot. Still, Kuschel has one more critical rule, even when all is going well. "You have to listen to what youre recording. Have a good pair of headphones and use them. Things can and will go wrong. Listen for distortion, hum, buzzes and crackles. You may be able to repair the problem quickly, or you might even jerk your whole audio assembly and revert to the camera mike. Then youll at least have some sound. If you don’t listen, you can record an entire shoot with bad audio (or no audio) and lose the project entirely."
The Great Outdoors
Often, your shooting location wont have the convenience of walls and electrical sockets. Nature provides us with beautiful audio potential, but capturing it is another matter entirely. The two biggest culprits in outdoor audio are wind and unwanted background noise.
Wind can ruin the most beautiful outdoor scenes. Problems arise from both the high and low frequencies of wind. At times it appears as a low frequency rumble, sounding sometimes like a small earthquake in progress. Your first stage of protection from low-frequency wind noise is the windscreen. Some camcorder mikes have a windscreen built onto the mike. But with external mikes, a windscreen is almost always an accessory item. The theory is simple enough: the windscreen keeps out the low-frequency rumble while allowing mid-level frequencies to come through.
The high-frequency sound of wind can also be a problem. Unlike the earthquake rumble of low-frequency wind noise, high-frequency wind noise sounds like the white noise found between stations on your AM radio. Windscreens have little effect on high-frequency wind noise. Professionals use a ‘wolfskin’ cover on top of their windscreen. These covers get their name from the wild animal fur they resemble.
Background noise can also create problems. You can frame a beautiful shot of the Grand Canyon to cut out the nearby parking lot, but its a lot more difficult to screen the sounds of the parking cars, slamming doors and screaming children.
Your first choice might be to try taping in more remote locations, or when off-screen activities are at a minimum. But there are times when wind and background noise will defeat even your best efforts at control. That’s where the concept of "wild" or "nat" (natural) sound can come in. This involves adding sound recorded at another time and place. Say youre capturing a waterfall on video. The best view of the falls may be from 50 yards. But at 50 yards, you may hear unwanted background noise. Why not shoot the video from 50 yards, then move in and shoot the audio from 10 yards? Later, you can merge sound and picture using the audio dub feature found on many high-quality VCRs. In fact, you should make a habit of shooting a little extra audio of the background noise at any location, even when you do not experience wind, background or other problems. Later, when you edit, you may find having first-generation wild sound from the scene is a lifesaver.
When shooting a windy or noisy scene where its certain the audio will be unusable, some videomakers prefer not to record audio at all. They simply add wild sound to the silent footage later. During editing, they dont have to put up with unwanted noise blasting through their system. If your camcorder has a manual audio level control, this is easy to accomplish. If it doesnt, simply insert a dummy plug into the external mike jack. This will disconnect the on-board mike and record silence.
Using wild sound can save you time and aggravation. Crowd noise, applause, thunder and rain, children playing, or birds singing on a quiet morning; all of these and more may best be recorded separately, when and where conditions permit. In fact, you may want to start a stock sound library. The modern camcorder has brought high-quality audio within the reach of almost everyone. Use this capability and your production values will soar.
Mastering location audio is not easy. But having the right equipment and knowing how to use it can bring your videos to a whole new level. As stated before, sound is responsible for at least 50% of the impact of motion pictures, so changing a good video into a bad one could be as simple as improving the quality of the audio tracks. The best time and place to fix them is when and where youre shooting the video.
Wireless mikes have opened up a whole new world for videomakers. One can achieve "close-miked" sound quality while keeping the camera free of restrictive cables.
The typical wireless mike system usually consists of 3 separate parts: the mike, the transmitter and the receiver. The mike and transmitter reside at the sound source, while the receiver remains with the camera.
Just as wireless mikes bring a new level of quality, they also bring on a new level of problems. To use them, you must constantly monitor your battery levels and watch for radio frequency interference (RFI).
To avoid problems, start with the best wireless system you can afford. Some of the lower-level systems have such limited range and quality that theyre nearly useless. Your system should be a VHF or UHF model.
Wireless lavaliers are the most common use of wireless mikes in videomaking, but theyre not the only way to go wireless. Its also possible to place a wireless mike on a fishpole boom or somewhere in the scene to record more than one person. Some videomakers record one channel with wireless, but back up the shoot with a wired mike on another channel. When all goes well, you can mix the 2 signals to add some ambience to your close miking.
Audio Horror Story
Chris Law is a video professional. But he feels his formal film-school training did not prepare him adequately for audio.
Law won a contract to record a piano concert by a local artist. This was a concert where obtaining quality audio was much more important than the video. To insure the highest quality, Law decided to take a house feed from the mixer. When the sound operator handed him a cable with a stereo-mini plug, he thought his problems were over. But just to insure that his levels were right, he closely watched the audio meters on his Hi8 Canon A-1 Digital and kept the levels below 0dB.
Heres where he made a critical mistake: he didn’t listen while he was recording. When he played back the tape at the end of the night, the sound was completely distorted and unusable.
As it turned out, the audio feed was a line-level output which Law had fed into a mike-level input. Though the meters indicated a proper level, the signal had overloaded the mike preamps when it first entered the camera. The line/mike demon had struck again. He had simply recorded distorted sound at a low level. The concert was a once-in-a-lifetime event for the performer. There was no excuse and no quick fix. A pair of headphones and an advance test would have completely avoided the problem.
What to do? Luckily, a DAT audio recording was made that same night by another attendee. Law was able to borrow the DAT recording and take his tapes to a professional studio where new audio was synced to the video in a time-consuming and expensive process. He learned the hard way, but he learned nonetheless; you can bet hell be monitoring his audio with headphones on all future shoots.