The most common approach to recording sound in a micro budget film is a single boom mic. Recording with a boom mic seems simple enough, just point it at the actors and roll camera. There are no pesky knobs or mixers to get in the way, and if you’re close enough to the actors you can hear them just fine without headphones. All the extra cables can be really annoying because they get all tangled up anyway. In reality one mic with no mixer or other gear actually requires a lot of effort, thought and planning.
The boom op must be a skilled technician who’s responsibility is to ensure the mic he is using is connected to the camera, and the input level is set correctly. This is done by adjusting the gain, the single most important element of all sound work. If you’re unfamiliar with gain, think of it as microphone sensitivity. The gain knob is usually the first control on all XLR input jacks. Getting the gain wrong can mean fuzzy, hissy background noise, low hard-to-hear sound or nasty distorted clipping sounds. Proper gain will ensure optimum signal to noise ratio while avoiding overloading the camera causing distortion and clipping. It will be necessary to readjust the gain for different actors, louder dialog, wider shots etc. Do not Set it and Forget it!
Mic placement is everything. I’ve seen boom mics lazily pointed sideways from several feet away, I’ve seen them held too high, pointed directly between two actors and all kinds of stuff that makes getting good sound nearly impossible. There is a better way. For starters, understand that a boom mic is designed to reject sound that is not directly in front of it. If you need to record a two shot where both actors are delivering dialogue, don’t split the difference and point the mic in between them. You’re going to have to look at the script and watch the blocking so you can ‘perform’ the scene with the actors. This can be difficult but the result is really amazing.
Move that boom around, and listen carefully. You want to get as close as possible to the actors head for each line from every angle. Pay careful attention to the camera framing and movement. Off camera dialogue is normally covered in the reverse shot later so don’t move the mic for it. Stay with your on-screen actor, pointing the boom at his forehead from above and slightly in front as close to the frame as possible without getting in it. For outdoor shoots always use a zeppelin and wind sock (dead cat). If you’re indoors, take the zeppelin and dead cat off so you can get closer. Also pay close attention to non-dialogue sounds, like breaths and grunts. A great boom operator will get all these sounds.
Where you stand is also important. Your body and arms have to stay out of the camera frame, and the boom can not cast a shadow anywhere in the frame. A boom operator should also stay out of the sight lines of the actor, and avoid looking into his eyes. This can be very distracting to the actor. However, I suggest looking at his forehead in order to keep your boom positioned correctly.
If you are using a mixer or mic pre with the boom you must be sure to listen to the correct audio source. The only way to know what is being recorded, and consequently what you will have to deal with in editing is to listen to the camera output, not the mixer. This is done by plugging headphones into the camera and/or using the RCA line out jacks connected to a headphone amp or mixer. Either way, you are listening to the sound after it is recorded. You have to listen at high enough volume levels to overcome the natural acoustics of the room. I suggest getting some high quality headphones or in-ear monitors. Be prepared for latency, a delay between the sound in the room and the sound in the headphones. This is caused by the camera processing the analog sound into digital and back to analog for the headphones. But don’t worry, there will not be a delay when you review the footage and the sync will be intact.
In review, check the gain, be aware of the camera frame, get the mic as close as possible in every shot, move with your actor, and listen on headphones.
