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Mixing Matters:
Who Hears It and How?
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The sound mixing business is all about perceptions, how one sound is perceived relative to another. A listener’s surroundings can affect how and what they hear. We in the sound mixing game have to anticipate how listener’s perceptions can differ as they hear our work delivered to their own environments through a crazy patchwork of new and old standards and practices. Some audio is routinely mixed as loudly as possible, some more conservatively. Sometimes we exploit contrasts between loud and soft and sometimes we try to do just the opposite. Why? Here is a primer course.
Targeted Mixing
Before starting a project here at Pharoah Editorial, we always ask our client to spell out exactly how the final mix will be used. Is it for film, DVD, broadcast, the web? Who will hear it and where will they be? How many people will be in the same room? My working life would certainly be easier if we mixed only one style, like only for radio or advertising, or only pop music. We do those things but more often we mix for television broadcast or film theater release. Sometimes our mixes are streamed across the internet. Each medium has different technical requirements and mixing approaches.
Many of our clients target multiple outlets for their work and they nearly always want to use one sound mix for all of them. We like to save money too but that may not be the best way to do it. Consider how a film is heard. Film theaters deliver a captive audience, you, into a darkened, acoustically treated room and surrounds you with full range speaker systems that are capable of superb reproduction. If you’re watching television, on the other hand, you’re probably dependent upon whatever receiver/monitor happens to be standing against the wall. Sound spews out of it as loudly (or softly) as you decide and it is nearly always competing with the sounds of real life (kids fighting, air conditioner humming, burgers sizzling, etc.). Internet streaming, by comparison, might play directly into your ear buds or tinny computer speakers at your fingertips, or maybe you’ve invested in a kick-ass surround-sound gaming setup. Furthermore, some playbacks will be in full surround, some stereo (maybe “stereo” but with a channel broken!), and some in glorious mono!
With so many variations of playback there is just no way that a single mix will sound perfect in all of them. A good mix should sound good everywhere, they say, but sometimes the only solution I can come up with is to provide different mixes for different uses. The big film theater debut gets a mix balanced just for it, the broadcast gets a variation that satisfies the needs of broadcast (but that is not ideal for a film theater), and a third version is made to compete on the internet. Depending on the material and a willingness to accept compromise, sometimes we can roll a theatrical and broadcast mix into a single version.
Hear It Like They Do
As we work we are always asking ourselves things like, is the music loud enough here? Is the voice quality pleasing and is it easily understood? Does a scene’s overall content and volume help convey an appropriate mood? Is there a good balance of bass and treble sound? Are there undesirable noises we can reduce or eliminate? Like it or not, the answers can be different if we listen on, say, a laptop computer or a really nice sound system.
Human hearing is a marvelous thing but it is not perfect. Most people just assume that what they hear at any moment is exactly the same as what anyone else will hear. The truth is, our perceptions are altered by the circumstances of playback. For one thing, our ability to discern different sounds is reduced at low sound levels and increased at louder levels. Music that is nicely balanced under dialog may suddenly seem too intense when the overall volume is turned up. The reverse is also true. Take the soundtrack of your favorite Hollywood blockbuster action film. When you first heard it in the film theater, you were probably swept up by the story and thrilling action. Music was thumping, explosions were chest-pumping, dialog was perfectly intelligible, altogether it was probably a very fun and satisfying experience. Play the same mix on your home TV set and you will need to keep a hand on the remote control! Music and sound effects can blast out only to be followed by dialog that is barely audible, and subtle sounds like clothing rustles or footsteps are often inaudible. Your perceptions, expectations, and listening needs are not being satisfied at home in the same way they were in the theater. What works for one may not work for the other and we have to adjust our mixes accordingly. The more possibilities we try to cover with a single mix, the more compromises must be made. We therefore strongly believe that a program should be mixed, or at least checked and adjusted, under conditions that are reasonably close to how we expect an audience will hear it. Top quality broadcast mixes require checks in mono, stereo, and surround on different speaker systems. Even with experience, multiple checks take extra time.
Different Strokes
Feature films of the last several decades are mixed to taste, with a wide “dynamic range”. Whispers are soft, shouts are loud, and music and sound effects can be awesome as they heighten the drama in ways that, put simply, “just feel right”. Many of these dynamic traits are opposite the demands of broadcast specifications that encourage uniform volume levels. In the feature film world, theater sound is well controlled. Rooms are tuned and calibrated using playback standards that are meant to allow for moments of exceptionally loud sound (a properly calibrated theater sound system can sustain ear-damaging levels on demand), along with excellent clarity of even the softest moments. Film makers strive to deliver a comfortable and satisfying experience to their audience and they mix their films in a room that adheres to the same standards as theaters. Playback uniformity in theaters allows a film to sound equally good from theater to theater, and has worked reasonably well for decades. Taste and artistry guide the sound mixing process.
Our broadcast world is not as refined as feature film. Mixes go through many legs of a distribution chain, each of which can (and often do) alter our mix, and it is the viewer who is in charge of sound playback. There are no playback standards or predictable room calibrations within the viewer’s home. The audience can hardly be considered “captive” and our mixes compete with real life activities and distractions. At the same time, our mixes are subject to much more severe technical limitations than those required for film theaters. Webcasts and podcasts, like broadcast, can encounter wide playback scenarios but unlike either feature film or television, they tend to be mixed as loudly as possible to the brink of digital limitations. (This relatively new practice is probably a carryover from the world of popular music ruled by an idea that “louder is always better.”) It stands to reason that these three playback scenarios, film theater, broadcast, and internet streaming, will require three different mix approaches. In order to deliver a satisfying sound mix we must know who will hear the mix, on what equipment, and under what circumstances.
“I canna change the laws of physics”
- Scotty, 1966
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| Mixing Matters is an open-ended series of short, easy-to-digest articles about some of the grey corners in our world of sound mixing for film and television.
©2009 Richard Fairbanks
Do not quote or copy without prior written consent
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