Where To Mount Your Microphone
Where do you think is a good place to set up your microphone?
Audio and sound beginners typically mount a microphone on top of their new camera, but it’s probably one of the worst places you can place it. There are many reasons why, but an important one is that when you mount it there, the microphone is often too far from the subject to pick up a clean, clear sound.Another problem is signal-to-noise ratio, often written as “S/N ratio” or just “S/N.” It refers to the amount of signal—or desired sound—versus the amount of noise—or undesirable sound that’s picked up. The closer the microphone is to the subject, the more signal, and less noise, it will pick up.
So, when you mount a microphone on top of a camera, with today’s typically longer zoom ranges, the look of the shot is often most flattering when the camera is located farther from the subject, requiring the operator to zoom in on the subject or use a longer telephoto lens. This allows the longer focal-length lenses to compress the foreground, mid-ground and background, producing a softening of the background and giving a dreamy, poetic look and feel to the shot.
But here’s the problem: If you’re moving your camera farther away from your subject and the microphone is tagging along on top of your camera for the ride, you’ve just added in a lot of noise to the recording while reducing the signal the microphone can pick up since you have increased the distance of the microphone from the subject.
However, I’m not saying having a microphone mounted on a camera is totally useless. It’s not. On-camera mics can be handy for recording scratch tracks that can be matched up with better-quality recordings in post. Also, on-camera mics are fine for recording ambient or environmental sound. Just don’t rely on a camera-mounted mic to record talent very effectively.
The Importance Of A Microphone Boom Pole
Almost anyone who has ever watched behind-the-scenes footage of a television show or a Hollywood movie being filmed has seen a professional boom operator at work. They’re the ones you’ll often see holding a long boom pole over their heads and positioning the microphone as close to the talent as they can get.
Now, in my eyes, these pros are extremely talented. In fact, seeing a skilled boom operator maneuver a mic is like watching a skilled camera operator work handheld. Both jobs involve many subtleties, which add up to professional-level audio and video footage.
So, while my tips won’t magically turn you into a pro-level boom op, I hope this article helps you get a better sense of how to improve using a boom mic on your own productions.
A helpful way to understand audio, at least as far as gear goes, is to trace the signal path from the subject to the camera and/or recorded audio. With an audio boom pole setup, we generally have five different components that make up this signal chain, which includes the following devices and pieces of gear to produce a signal:
1. Microphone: Since we’re talking boom microphones in this article (and not lavalier microphones), it’s safe to say that in professional sound for picture work, generally, the signal chain will begin with a shotgun or cardioid-variant (cardioid, super-cardioid or hyper-cardioid) microphone. Usually, the shotgun microphone will have a narrower angle of acceptance of sounds than a cardioid variant, rejecting more noise while recording more signal. There’s a lot more to it than that, but for this article, I won’t go into specifics. Just know that there are many effective and high-quality microphones that are typically used on boom poles at many different price and sound characteristic levels.
2. Wind Protection: Most boom microphones used in video and television productions are powered condenser mics that are typically very sensitive and can pick up even subtle or nuanced sounds, including HVAC, wind or other air movements quite easily. So, it’s always a good idea to use a foam, softie or microphone zeppelin when recording with a boom pole. These condenser microphones generally come from the manufacturer with a foam microphone cover. You can use them for interiors or exteriors, but once you move outside, you’ll need to use a softie or microphone zeppelin. A softie is generally a fur-covered slip-on cover that covers the front two-thirds of the microphone, offering a dramatic reduction in wind noise. The fur on a softie breaks up wind and greatly reduces or even eliminates most wind buffeting. However, a softie leaves the rear of the microphone element uncovered. For the maximum protection from wind noise, a plastic capsule that completely encloses the microphone is preferred. The zeppelin has a foam windscreen over the entire surface of the mic, and sound mixers can also add a fur-covered windscreen, often referred to as a “dead cat,” to the zeppelin. This adds even more wind reduction without dampening high frequencies.
3. Microphone Mount: Most sensitive condenser microphones will pick up and amplify handling noise. But a high-quality microphone mount lets the boom operator manipulate the microphone into position while significantly reducing handling noise. And remember that some mics are very sensitive to handling noise. So use a good microphone mount help to limit those sorts of unwanted sounds.
4. Audio Boom Pole: Audio boom poles are designed to easily and efficiently allow a boom operator to quickly and precisely move a microphone into position above the talent’s head, just out of frame line. It’s why you wouldn’t just use Gaffer tape to stick your microphone onto a house painter’s pole that costs $5: Your DIY pole just won’t allow you to place a microphone in a specific position precisely, easily and quickly. Audio boom poles come in many different lengths and diameters. Some are internally cabled, while others are externally cabled. And you can find them in several different materials, including aluminum, fiberglass and carbon fiber. As you might expect, since you’re the one who will be holding the boom pole, microphone mount and microphone over your head, weight is the most important factor in choosing a boom pole. In short, lighter is always better when it comes to boom poles. Most audio boom poles terminate in a male ¼”-20 or 3/8” male-threaded fitting, and, not coincidentally, most microphone mounts terminate in a ¼”-20 or 3/8” female thread for mounting the microphone mount and microphone to the boom pole.
5. XLR Cable: The outputs on most pro microphones are three-pin XLR audio outputs. We also most typically use XLR cables with a male XLR connector on one end and a female XLR on the opposite end. Higher-quality XLR cables are easier to coil and uncoil, have greater noise rejection and will generally last much longer than cheap XLR cables.
Boom Operator Tips
Now that we’ve broken down all of the components of a boom-pole microphone setup, let’s talk about some tricks and tips of the trade to more effectively use a boom-mounted microphone system.
- Most often, you’ll place the boom above talent and point the mic down at talent’s chest cavity, which will yield the highest-quality audio. There are situations where booming from underneath the frame may work better, but generally overhead booming is best so that the microphone picks up less ambient sound behind the talent.
- Begin with the microphone fully visible, in frame, then raise it until the camera operator says that the mic has cleared the frame. As a boom operator, mentally draw a box around the talent that approximates the frame the camera is capturing. Then, place the boom mic as close to the edge of that imaginary frame as possible but keep it out of frame.
- Wrap a light-colored piece of paper tape or gaffer tape around the end of the foam, softie or zeppelin. This lets the camera operator see if the tip of your mic intrudes into the video frame. If possible, try to work out a set of visual signals with the camera operator so that if they change the framing and your microphone ends up in the frame, you’ll respond by raising it up and out of frame. This can range from simple hand signals to watching the camera operator’s eyes or head signals when they need you to raise the boom and clear the frame.
- If the camera is locked off, there’s often no reason to hand-boom a scene or interview. Boom operators often place their boom pole onto a C-stand or light stand with a boom-pole holder when shooting a long, locked-off scene. That’s because your arms will get shaky the longer you hold the boom pole above your head. So, use a mic stand wherever possible to save your strength for when you have to hand-boom a scene. You can also place a pillow or sandbag on top of a light stand and rest your leading arm on it for scenes with more than one talent where you still need to rotate your boom pole to pick up more than a single talent.
- When booming overhead, keep your lead arm—the one closest to the microphone—locked. You should also try to position the elbow of your lead arm close to your head. Positioning your arms in this manner allows you to hold the pole steady during long takes while also preventing muscle strain. Your rear arm functions as a tilt-and-swing control. Use it to position the mic and pole wherever you need them. To smoothly move the mic from actor to actor, rotate the boom pole using your fingertips. In scenes with two or three actors, it’s common for one boom operator to cover the lines from all the actors. If there are more than three actors, it’s best to cover those scenes with two or more boom operators and poles.
- It’s extremely helpful if the boom operator can wear headphones to hear the sound that the microphones pick up. In fact, there are special duplex cables available for headphones that will allow the mixer and the boom operator to both hear what the boom microphone, as well as other microphones, are recording.