Sound Advice: Audio for Interviews

Getting quality audio when you tape an interview seems like a no-brainer because the subject just sits in one spot in a quiet room and talks. Step one: aim camcorder; step two: roll tape. What could possibly go wrong?
Step three: harvest hair by tearing it off your head during post production because of lousy sound quality. Why? Because the subject and mike sound as if they were in different counties or the interviewer sounds trapped in a 55-gallon drum or both interviewer and interviewee garble their words together so much that a neurosurgeon couldn't cut 'em apart.
In short, there's more to interview audio than meets the ear and most problems arise from mike-to-subject distance, inconsistent sound quality and/or failure to keep the subject's audio separate from the interviewer's. Fortunately, these problems are solvable if you know where to look for them and how to cope with them. That's our homily for today. We'll review options in choosing and placing microphones, procedures for setting up and recording interviews, and strategies for both two-person (interviewer on camera) and one-person (subject only) interviews.

The big problem with all interviews is that video and audio have opposite requirements: the camera should be as far from the subject as space permits, while the microphone must sneak in as close as it can get. The camcorder should be placed well back from the subject, for three reasons:
1. A camera is less intimidating when it stays out of the subject's face. Ideally, the interviewee should gradually forget the camera completely.
2. A distant camera requires mild telephoto lens settings, which are generally more flattering to subjects.
3. A long camera throw allows greater flexibility in positioning lights.
In contrast, a microphone should be as close as possible to enhance voice quality and exclude unwanted background sounds(see Figure 1). The obvious solution is to separate video and audio hardware by using an external mike. This is practical for even the most low-rent enterprise because Azden, Radio Shack and others offer very competent mikes for under $100 - way under $100.
My first choice is a lavaliere (tie clip) mike because this design is engineered specifically for interview-style applications. I like cabled lavs because wireless is no advantage when the subject doesn't move around, and hard-wired mikes are not subject to radio interference especially when using low impedance, balanced lines. (For more on this see the February 1998 Sound Track or find it online here).
On the other hand, if your budget permits only one set of mikes, you may prefer wireless lapel mikes for their versatility when in use in other, non-studio situations.

The next best option is a boom mike. A fishpole is fine for a multi-setup production where no shot runs longer than a few minutes; but holding a pole aloft through a half-hour interview can reduce the buffest biceps to old rubber bands.
An inexpensive shotgun mount works well on a boom, unless its sensitivity pattern is extremely narrow. You may also want to consider the more forgiving pickup pattern of a cardioid mike. Positioned between subjects, at right angles to the axis between them, a boom mike can quickly swivel back and forth to catch both people.
Finally, you might try a short stand mike, especially if your subjects are sitting on opposite sides of a table. With careful composition, you can keep the mike below the frame line. A boundary mike can be used in this situation too, also known as a Pressure Zone Microphone, the (PZM) is both unobtrusive and effective. A PZM lies flat on a hard surface like a table or podium.
But what if you're stuck with your built-in camcorder mike? Then set up a video/audio compromise, like this:

• Set the camera lens about half-way between wide angle and telephoto positions, avoiding wide-angle settings that distort facial features.
  
• Move the camera as close as you can while still framing a classic closeup (head, neck, tops of shoulders). That way, you can zoom in to tight closeup for an alternative angle.
  
• Give the subject plenty of warm-up time so they can get used to your lights and the looming camcorder.

What happens to the interviewer's audio quality when the mike is aimed at the subject throughout? That depends on your recording strategy: how you want to capture audio for later editing.