Sound Track: Interview Audio

Interview--it's a harmless, innocent-looking word, isn't it?

At first glance, maybe. But start to dig into all that one little word can mean, and things get complex rather quickly. You see, there's no such thing as the "standard" interview. The seemingly simple act of capturing intelligent interaction between two or more people is the product of about a thousand factors.

Interviews can be indoors or out, pre-planned or spontaneous, between just two people or a whole herd, stationary or clipping along at a jogger's pace. Think one stock approach is going to achieve success in every situation? Think again.

This month's column focuses on the most common shooting situations you'll find yourself in when capturing interviews. We won't cover how to ask open-ended questions, how to stage your talent or how to get past the CEO's secretary--those are topics better served elsewhere. We're going to explore how to get the best-sounding audio down on tape, and what to do with it once it's there.

Before we dive in, let's cover a few general techniques that apply to all interview audio. First off, the cardinal rule of good audio applies especially to interviews: use an external mike (or mikes) whenever possible. The camcorder's built-in mike may work up-close in very quiet locales, but this rarely describes the real world.

Second, if you're recording two people, such as interviewer and interviewee, you'll get considerably better results if you have a stereo camcorder and can record two external mikes separately onto the left and right tracks. During editing, you can then control the level, tone and noise with an audio mixer to get a better match between the two voices. If you record the two voices onto a mono track, you'll have much less control during editing.

Finally, use headphones to monitor the audio going to tape. It's mighty discouraging to play your raw footage and discover you've shot the world's first silent interview. Play it safe--use headphones.

Interviews, Sans Talent
Let's start with the simplest interview approach of all, where the videographer asks questions from behind the camcorder. This is most common when shooting spontaneous, single-person interviews where you can't lock the camcorder down on a tripod and get in the shot yourself. While this type of interview may have a "hokey" feel to it, it can be effective for certain types of programs. It is far less hokey if you mike yourself as well as the talent. Videographer Skip Blumberg, for example, has made good use of this technique, getting his subjects to answer questions while looking straight into the lens. It is also possible to ask questions from behind the camera that you edit out later. With skillful questioning, it is possible to edit together a coherent interview in which the questions are never heard. Without the proper miking or editing, though, this type of interview is fraught with compromises and should be avoided.

If your camcorder's built-in mike is all you've got, be sure to get as close as possible to your interviewee. Slightly better than relying on the built-in mike is using a single external mike. If you've got a handheld mike, give it to your interviewee and raise your own voice. With a lav mike, the choice is obvious: pin it on your subject. Don't think you're going to fool anyone with this approach. It will be painfully obvious to all who see your program that you were shouting towards the only mike available. Hopefully, you can edit your interview to eliminate your questions entirely.

If you have to conduct your interviews without help, the optimum situation involves two mikes. Pin a lavalier on yourself to pick up clean, clear questions. Give your interviewee a handheld or lavalier mike for similar audio quality. Ambient noise will melt into the background, and your questions will carry the more "legitimate" air of the off-camera interviewer.

If you have a single shotgun mike, enlist a helper to aim it at whomever is talking. Have him stand just outside the frame, splitting the distance between camcorder and interviewee. While not as nice as two external mikes, this approach will usually sound much better than sharing the on-camera mike. If you can get within about 10 feet of your interviewee, the shotgun mike will pick up clean, full-sounding audio from both parties. Try to keep just one person talking at a time, as the highly directional mike will reject whichever voice it's not pointing directly at.

You've Got Talent
Getting an interviewer on-camera is the next step up in production value. If you must use the on-camera mike, get your camcorder as close as possible to the action. Adding just a single external mike will improve audio quality dramatically, especially if it's a handheld type. Have your interviewer hold the mike, steering it towards whichever mouth is moving at the time. Passing the mike back and forth between interviewer and interviewee looks clumsy, and can introduce a lot of handling noise. Coach your interviewer on the importance of keeping the mike pointed squarely at the speaker, from a constant distance. Waving the mike around causes erratic record levels and inconsistent voice tone.

If you have just a single lavalier mike, you can get passable audio by pinning it onto your interviewee. Cheat the mike towards the interviewer, and encourage him or her to speak loudly. Two lavaliers are optimum, giving you crisp, clear audio from both people. Two handheld mikes work very well also, and give your subjects' hands something to do besides fidget. The shotgun-mike approach mentioned earlier works well in this situation--pros use it frequently for spontaneous, fast-moving interviews.

Another option, at least for quiet shooting locations, is to hide a lavalier somewhere between the two people. Try placing it in a plant sitting on a coffee table, or suspend it just out of the frame from above. The closer to the two subjects the mike is, the better the resulting audio will sound. There's no rule saying you can't try using a directional handheld mike in this role. With two people standing behind a workbench, I once taped a directional mike to the bench directly between them. It pointed straight up, capturing crisp interview audio from just out of the camcorder's view. Necessity truly is the mother of invention.

Group Dynamics
Interviewing groups can be one of the tougher assignments for any videographer. Not only does it pose challenges visually, but recording clear audio from numerous people takes a bit of planning. For both the look and sound of the interview, encourage your many subjects to get as close to one another as possible.

Strange as it is, the acoustics of your shooting space will play a big part in choosing your miking approach for interviewing groups. The amount of reflected sound picked up by the mike dictates how "up- close" your interviewees sound. Too much reflected sound (reverb) makes them seem distant and indistinct; small amounts of reverb makes them seem closer and more articulate. If you're interviewing a group of people in a quiet, outdoor location, you'll have almost no reflected sound at all. The same goes for a carpeted, well-furnished room. The more padded furniture and draperies, the better. Distant miking (built-in or, preferably, shotgun) may work very well in these situations.

When using a single mike to pick up multiple interviewees, you'll be better off with an external mike. This will get the mike away from the motor and button noises from the camcorder, and will also minimize the chances of you muttering something that inadvertently ends up on tape. Because the ear finds it hard to decipher speech when more than one person is speaking on video, make sure that people don't talk over one another. Listen for loud, distracting noises from off-camera. They may signal the time for a re-take.

Use the same distant-mike approach in a gymnasium, and you won't be able to distinguish the voices from reflected sound. Where reflected sound is strong, you must get a mike extremely close to whomever is speaking. Your best bet in this situation is to use two directional handheld mikes--one for your interviewer, and one passed between interviewees. Putting a lavalier mike on each member of a large group (a whole gymnastic team, for example) is clearly impractical.

If you script the questions and let the group know the order ahead of time, each interviewee can pass the handheld mike to the next while the question is being posed. An assistant can even stand behind the interviewer with "cue" cards, showing the interviewees the name of the next person who will speak. When one answer is finished, the mike can move off to the next person quickly. Here's where recording to two separate tracks becomes important--you can mute the handheld mike as it's jostling its way towards the next interviewee.

Fix It in the Mix
By its nature, the interview usually has a "back-and-forth" audio content. When the interviewer is speaking, the interviewee (or group of interviewees) generally is not, and vice-versa. This frees up some possibilities for fixing poor audio, while presenting some unique challenges.

The best tool for cleaning up interview tracks is the audio mixer. The most suitable type of mixer for this application offers true faders to control levels, an equalizer for making tonal adjustments and on/off buttons for muting tracks. A number of inexpensive mixers offers these basic functions.

Sound-level fluctuation is a common problem during interviews. The reasons are legion: people speak at different volumes, mikes offer varying output levels, shotgun mike operators can fall asleep and subjects can shift away from your carefully "centered" mike. Even if you captured your interview on just one track, you can still adjust the fader on the fly to even out the levels. We call this "riding" the fader, and it does take some practice. In time, however, you'll be able to make seamless changes to keep levels consistent.

What you can't do with a mixer is change equalization (EQ) settings quickly. If one voice sounds muddy and the other thin, no one setting will take care of both, and it's too hard to ride the fader and twist EQ knobs at the same time. This is where having two mikes on two channels becomes handy-- you can make different tonal changes for each mike to achieve a more consistent sound. The dark-sounding mike will benefit from a low-frequency cut, while the thin-sounding mike may need a reduction in midrange frequencies.

Splitting your audio between two tracks allows you to reduce the level of whichever mike is not in use at that instant. You can do this by toggling mute buttons on and off, or you can lower the fader of the unused channel. Even when a mixer has mute buttons, some people prefer to use the faders. Here's why: reducing the level of the "idle" channel just part of the way effectively eliminates handling noises or other unwanted sounds--you don't need to mute the channel fully. Since you've attenuated the fader only partly, you won't completely lose that mike should someone begin speaking into it unexpectedly. If this happens, you can smoothly return that channel to full volume. Moving the fader creates a much less jarring transition than instantly unmuting a channel.

There are pieces of audio equipment you can purchase that will perform some of these functions automatically. The compressor is one example. It functions like a tiny soundperson in a box, decreasing the differences in sound level of whatever you run through it. The compressor will help smooth out two mikes that differ greatly in volume, and it reacts to level changes much faster than any human can. The main drawback of a compressor is that it tends to bring up noise (tape hiss or background sounds). Many compressors include a "noise gate" for this very reason.

A noise gate is almost like a pressure valve for audio. It reduces the level of sounds that are below a user-set level. If a sound isn't loud enough (hasn't enough "pressure"), the gate stops it; if it's above the pre-set level, the gate lets it through. With a noise gate set to reduce background noises and let voices through, you'll get a much cleaner sound. This works very well with a two-channel recording. The gate will quiet whichever mike is idle, greatly reducing competing noises. When someone speaks into the mike, the gate quickly lets the signal through.

The interview is not the easiest thing you'll ever record. Approach it with the right tools and techniques, however, and your interviews will sound great.