Image licensed by Ingram Publishing.
The very first movies didn’t have sound, which meant squeezing a piano into the theater to add some musical excitement. Today, people like Rich Hamilton make sure we hear every word our favorite character speaks, shouts, and whispers. While that means less work for piano players, it makes a better movie-going experience for us. Bedtime Math sat down with Rich to learn about every angle of his work as a Production Sound Mixer and Boom Operator.
BTM: First of all, why do you love your job?
Rich: Well, sound is an important part of movies that a lot of people forget about. I also get to meet lots of interesting people and go to cool places – like the top of Mt. Kilimanjaro in Tanzania.
BTM: So what does your job title mean?
Rich: It basically means I’m in charge of the sound on a movie set – making sure the audience will be able to hear what the actors are saying. That might mean holding a giant “boom” microphone over someone’s head or watching the levels of all the different mics.
BTM: We’ll get to what “levels” are in a bit, but first can you tell us how you set up to record sound for a scene?
Rich: We usually start planning with something called a “blocking rehearsal,” where the actors and camera operator go through all the movements they’ll make in the scene. That helps us figure out where we can record sound from, because no one wants a sound person or microphone to end up on the screen. If the camera is shooting a close-up, which is just the actor’s face, we can put the microphone basically on top of the actor, as in 3 inches above their head.
BTM: Why so close?
Rich: Recording good sound is all about getting the best “angle of attack.” The best sound comes from having a microphone pointing straight down, 90 degrees, and positioned a few inches in front of the person speaking, so you catch the sound as it leaves their mouth. I’ve ended up on ladders or even in the rafters of buildings to get the “magic number” of decibels, which is -12 dB for an actor’s voice.
BTM: How do you adjust to an actor screaming or whispering, if you’re trying to stay at the magic -12 dB?
Rich: There are 2 ways to deal with that – I can move the mic closer or farther away from the actor, or turn the volume down on the recorder that the microphone is feeding into. When I’m moving the mic, it’s important to remember that decibels are a logarithmic measurement, so it’s not a directly proportional or 1-to-1 relationship between the distance and sound intensity. If I cut the distance between the mic and the actor’s mouth in half, the sound won’t be 2 times as intense, it will be 4. So I have to be very precise, because sound and the equipment are both very sensitive to distances and the surroundings.
BTM: Can you imagine doing your job without math skills?
Rich: I don’t think I could. I can’t imagine the director or actors would be very happy with me, and I might hurt a lot of people’s ears – or at least my own!
BTM: What are the most important math skills you use every day?
Rich: It all starts with counting, adding, and multiplying in the planning phase – if there are x actors, then I need y mics, and z batteries. Then there’s the spatial reasoning and geometric planning – calculating distance, heights, and angles to be in the best spot to record. And there’s also watching the dB levels and doing quick mental math and adjustments to keep them steady. Like a lot of other jobs, this one is about thinking quickly on your feet.