Sound for documentary, Part 1: Eight fundamental concepts
March 4, 2013
Between widespread access to affordable camcorders and the rising ubiquity of mobile phones with good video cameras, along with the ascendancy of YouTube as a major media diffusion platform, it’s never been easier to produce and share documentary videos. Across the board, however, sound is the achilles heel of many videos. While it is relatively easy to shoot with a camera, the art of positioning a microphone, monitoring, and setting levels remains an elusive mystery compared to the workings of the video camera.
This post is the first in a multi-post series on this blog that will collectively present an overview of practical techniques and a guide to the basic tools for recording, editing, and mixing sound for documentary video. Collectively these posts will help you improve your work whether you are a beginner, intermediate, or experienced media maker. Whether you are shooting with a mobile phone, consumer camcorder, D-SLR, prosumer or professional camcorder, sound is an important element of the documentary makers craft. We’ll cover the range of consumer, prosumer, and professional gear, since as documentary makers we find ourselves (more and more it seems) working in a wide range of situations, each requiring a different set of gear. Surprisingly good results can be obtained with consumer gear in a wide range of circumstances yet professional gear provides specific affordances, so we’ll cover both along the way. Throughout the series you’ll find links to resources for further study and some gear recommendations based on real world experience.
In our first installment we’ll start with an overview of eight fundamental concepts that will guide our discussion of sound for documentary throughout the series. Here we go, let’s dive in.
1. Sound coveys emotion, picture coveys information
Think of the scene in Jaws of a woman swimming in silence. Now add those two famous bass notes. A totally different experience. Consider the emotional impact. Sound carries the emotion of your video, it’s half of the picture. Paying attention to sound, both in terms of good recording and how it’s mixed and the use of sound effects and music, can make a real difference. Even if you’re only doing a simple interview with dialog only, a rich sounding human voice will make a difference. You’ll find a wonderful collection of essays at FilmSound.org by Randy Thom who worked on Apocalypse Now as a sound effects recordist back in the day and since then has worked on an impressive number of films and has received multiple Academy Awards for sound. Thanks to G. John Garrett for this Jaws example.
2. Viewers expect transparent audio
Several years ago while preparing a presentation for New Media Expo in Los Vegas I visited Vimeo to find some videos to show as examples during my session. I was amused when I came across the video shown above: the filmmaker left a note saying that he would be fixing the sound as soon as possible. We usually don’t apologize for slight imperfections in terms of our video image quality, as most viewers will overlook them, but sound is different. Peter knew he had to say something about the sound issues in his piece in order to reassure his viewers he would soon be fixing the sound (which he knew would bother them). Sound is that important. People expect transparent (good) sound.
3. Microphone placement and noise management are the primary factors differentiating amateur and professional recordings
The problem with most amateur sound recordings is excessive ambient noise from a variety of sources and low sound levels (relative to the ambient noise). As a result, it’s difficult to understand dialog, and emotional impact suffers. This situation usually boils down to improper microphone placement. Learn to listen to your recordings and experiment with different microphone types and placement options. Getting the microphone as close as practical to the sound you want and as far away as possible from unwanted noise is a good starting point. In addition, when recording outdoors, you’ll probably need to control wind noise with a windjammer. In a future post we’ll cover microphone placement in detail and discuss different types of microphones and what task each is best suited for. With a litte bit of study and a healthy amount of practice, you can obtain very good recordings, regardless whether you are using consumer or professional gear. Placement and controlling noise are much more important factors determining your final result than the cost of the gear you are using.
4. Setting proper levels and monitoring your recording is crucial
For the best recording you’ll need to actively set recording levels. Not too loud to avoid distortion. Not too soft so your sound is not lost in the noise. Always monitor what you are recording with good over-the-ear headphones (or quality in-ear fitted earbuds that provide good sound isolation) so there are no surprises while editing. With digital recording devices you can’t record anything beyond full scale (indicated as O dBfs on most meters) so if you exceed this limit your recording will sound terrible, unless your camera or sound recorder has automatic gain control (AGC), a circuit that automatically adjusts recording levels, or a limiter, a circuit that can automatically soften audio peaks without changing the overall sound level. In a subsequent post we’ll dive into reading meters, setting levels, using a limiter and even AGC in a pinch (though right off the bat I’ll say that in most cases AGC is not a substitute for manually setting levels, but with some consumer gear you will not have a choice).
5. Don’t buy into the shotgun myth
Shotgun microphones don’t “reach” farther, they don’t work like a telephoto lens. Sound, unlike light, is promiscuous, it travels in all directions and goes around corners. Shotgun microphones have their place, they are useful in noisy environments, especially when you can’t be as close to your subject as you’d like, however, they do not perform magic. Instead of reaching farther, they respond to off-axis sound differently in terms of reduced level, coloration, and a null point. They might look impressive, but many recording situations call for other types of microphones. In subsequent posts we’ll go into detail about various microphone types, pick-up patterns, how they differ, and in what situations you’ll want to use each of the microphones commonly used in documentary production. Given the choice between a $30 lavalier properly placed on a person talking vs. a $2,000 shotgun microphone mounted on the camera too far from the subject, I’ll take the $30 lavaliere. On the other hand, that $2,000 shotgun attached to a boom in the hands of a talented boom operator will certainly sound great, but it’s not always an option in terms of logistics, placement, or budget. This is why my first microphone purchase was a TRAM-50 lavaliere. I eventually followed that up with a shotgun microphone. Since the majority of the work I was doing in the beginning was interviews, I knew the lavaliere should be the priority. I’m lucky to have had good teachers who set me straight early on in my path as a documentary filmmaker.
6. Judicious use of compression and equalization can make a big difference during editing
Compression and equalization are two essential post-production audio effects you’ll want to become familar with and practice using them when editing the sound portion of your video. A bit of audio compression on dialog tracks can help them sound louder and cut through other sounds in the mix, but don’t overdo it. Some equalization (emphasizing some frequencies and/or deemphasizing others) will sweeten the sound of dialog, amibience, effects, and music. For example, through equalization you can make thin dialog sound a little richer through enhancement of the lower frequences and reduction of some of the high-to-middle frequencies. In a subsequent post we’ll dive into how to use these audio effects to balance and sweeten your audio tracks. Some effort in processing your sound tracks will pay huge dividends in how your video feels when you audience is watching/listening to it.
7. Eliminate the phrase “we’ll fix it in post” from your repertoire
“We’ll fix it in post” is a silly thing to say, if you record bad sound, it usually stays that way, it’s very hard to fix most poorly recorded sound. For example, if you record dialog with the microphone too far from the speaker in a reverberant room (think gymnasium acoustics), you’re going to get a series of multiple echoes from the hard walls mixed in with your dialog. You cannot fix this in post, reverb and most ambient noise is impossible to remove from the recording. There is no such thing as a remove reverberation filter and most noise removal filters do horrible things to the original sound. Record your sound effects and dialog as dry as possible by recording close to the source and controlling unwanted noise. You can take dialog that sounds too dry (because it was recorded too close to the microphone and thus has very little of the room characteristics in the recording) and add reverb and ambient sound. So get your recording right in the first place and add things like ambient noise and reverb later. Always record the sound of the spaces you work in order to build ambient sound beds you’ll use during editing. We’ll certainly spend more time on these issues in subsequent posts.
8. Consider spending as much on sound gear as you spend on camera and lighting gear
As a documentary maker you are usually recording both video and audio while observing subjects or doing interviews. You don’t just need a good camera, you need good microphones, the right accessories for mounting and support, as well as wind control, good cables, headphones, and possibly a mixer. Your investment in quality audio gear will pay off, and will most certainly outlast your camera. For example, I purchased a TRAM-50 lavaliere about thirteen years ago. It’s still a solid performer. I use it on the majority of my shoots (and even when I don’t it’s in my camera bag ready to go). Since that time I’ve gone through four video cameras. The video gear comes and goes but good sound gear is something you’ll have for a long time. My rule of thumb is spend about as much on your sound kit as you do on your camera kit. It’s a bit out of balance to spend $4,000. on a prosumer camcorder and expect to record all of your sound with only the stock microphone mounted on the camera. Even if you’re shooting with a consumer camcorder or an iPhone you can take your work to the next level with a good consumer-level microphone or two, and these will not set you back too much. When I suggest spending as much on sound gear as you do camera gear I don’t necessarily mean you should do this right off the bat if you are starting out, purchase gear slowly over time as you figure out what you need for your own style of shooting. If you can take, take gear out for a spin before you buy: either by attending a trade show, visiting a local retailer, renting from a local rental house, or borrowing from a friend. For a basic consumer-level starter kit, take a look at my recent post Basic Documentary Video Starter Kit (consumer level gear). I work with a mix of gear, some of it consumer-grade (e.g. the small lavaliere I often use with my iPhone) and other components are professional (e.g. my shotgun microphone and wireless lavalieres that I use with my Panasonic HPX170). Each tool has its place. We’ll go into detailed gear recommendations for a wide range of requirements and budgets in this series.
Until the next post, good night and good sound.
Continues in Part 2
Acknowledgments. I’m more of a camera person, I’m not really a sound person, however, I’ve had to learn along the way how to record, edit, and mix sound for my documentary work. I would like to thank Philip Perkins, G. John Garrett, Bill Shamlian, Peter Rea and Alex Griswold, five audio professionals from whom I’ve learned a lot about audio recording and post over the years. Any wisdom in this area I owe to them, any bad habits are strictly my own.
Photo credits: Jaws promotional materials copyright 1975 by Universal Pictures; sound recordist and boom microphone in a field: sound-hero by notArt; sound recordist with shotgun on a beach: shotgunning the wavicules by Strangeless; video editor at work: Jeffrey by bigredpenguin; other photos by the author.