​When you leave a movie theater, you're probably not thinking, "Man, the sound in that movie was mixed perfectly."

Don't worry, that doesn't mean you're bad at watching movies. The sound mix in a movie – the combination of the dialogue, soundtrack and sound effects – is designed to be unobtrusive. As one sound mixer put it to me, as soon as the audience notices something slightly off in the mix, "you've lost them."

If you don't notice a movie's sound mix, it doesn't mean you're bad at watching movies.

If you've seen Birdman, there's a good chance you did leave the theater impressed by Michael Keaton's acting chops. His character, Riggan Thomson, does a lot of emoting, walking and talking. It's fast-paced and fun — Aaron Sorkin's West Wing dropped into the back hallways of a Broadway theater.

But one of the most impressive parts of each of Keaton's conversations — even if you didn't notice it at the time — is that every word Keaton and his interlocutors speak is as clear as day.

If you're wondering who you should thank for that, it would be the Sound Mixing team behind the film. In recognition of that, Birdman — along with American Sniper, Interstellar, Whiplash and Unbroken — have been nominated for Best Achievement in Sound Mixing at this year's Academy Awards.



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Best Achievement in Sound Mixing is one of those awards that is announced throughout the broadcast to little fanfare — to the left you can see the extent of the coverage for the award in the New York Times' 2014 Oscars live blog, an outlet that devoted more space to sound mixing than most. And you probably won't see sound mixing among the pre-Oscars primers ("Who will win?! Who should win?")

The category's low profile can be explained, in part, because most of us don't really know what sound mixers actually do. The casual viewer doesn't always understand the artistry and technical mastery behind Oscar-worthy sound mixes.

To get some insights on the creation of film's sound mix – the combined elements of dialogue, sound effects and music – I talked to two former Oscar winners, one on each side of the process.

For the on-set perspective, I spoke with production sound mixer John Midgley, who won the 2012 Oscar in Sound Mixing for his work on Hugo and has been nominated twice more.

And to get an idea of what goes in post-production I talked to sound re-recording mixer Michael Semanick, who won the award twice for his work on King Kong in 2006 and The Lord of the Rings: The Return of the King in 2004, and has been nominated for his work on 7 other films since 2002.

Production Sound Mixer

TECHNICAL GENIUSES ON SET

John Midgley — Oscar Winner: 2012

Nominated: 2011, 2000

With the advance of audio technology and software, sound mixers can do more than ever in post-production to produce a great sound mix, from dubbing in re-recorded dialogue and reducing distortion and background noises, but there's only so much that can be done in post-production to rescue poorly recorded, distorted audio. So it's up to on-set production sound mixers like John Midgley to produce a good, clean recording.



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The production sound mixer oversees the audio recording as filming progresses, managing a crew of boom operators and other technicians. It's up to him or her to select the best equipment for each scene – from what kind of mics to use and where to place them, to directing where the boom operator should position the boom mic.

In addition to recording all the sound the director wants to keep in the movie, the production sound mixer is responsible for figuring out how to eliminate unwanted sound. "It really starts with [production sound mixers] on set being a pain in the ass," Semanick told me. This means Midgley has to figure out how to deal with everything "from noisy lights, equipment fans, mobile phones, to the footsteps of the actors clonking across the floor."

It really starts with those guys on the set being a pain in the ass.

For his work on Hugo, Midgley had to work around a number of challenges. From clocks that "weren't made out of the right materials" and made too much noise, to managing the sound created by the steam effects in scenes on a train concourse, to eliminating the noise made by the 3D camera rig used to shoot the film, there's a lot for a production sound mixer to work around.

Midgley singled out one scene in Hugo that presented particular difficulties for him and his crew, involving a Steadicam long take through numerous rooms in an apartment.

The footwork done by the boom mic operator to keep the boom mic close enough to record good sound while keeping himself and the mic out of the shot must have been nearly balletic – not to mention exhausting.

Beyond that, there is a lot going on in this shot: multiple groups of people talking simultaneously in different parts of the set, a band playing in the background, as well as the usual miscellaneous sounds – from footsteps, to noise generated by the camera rig, to crew members who just won't shut up.

When I asked for his thoughts about the 2015 nominees, Midgley was effusive in his praise for the technical prowess showcased in "Birdman." In particular, he drew my attention to the film's Steadicam scenes, one of which is particularly similar to the apartment scene in Hugo.

Midgley drew attention to the intricacy of the mic work ("God knows how the boom operators kept out of shot!") and the remarkable clarity of the dialogue amid the sonic chaos of Midtown Manhattan.

Sound Re-Recording Mixers

MAESTROS IN THE STUDIO

Michael Semanick — Oscar Winner: 2006, 2004; Nominated: 2014, 2012, 2011, 2009, 2008, 2003, 2002

Once filming has wrapped, the production sound mixer hands over the audio to the team of sound re-recording mixers, who usually work in pairs or threesomes. The teams split three facets of post-production sound mixing: dialogue, music and sound effects.



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Whereas the on-set aspect of sound mixing is defined by the technical challenges that must be overcome by a production sound mixer, the post-production aspect is defined by molding that audio into a balanced storytelling device.

In addition to the technical aspect of post-production mixing — mixing the dialogue, music and effects to harmonious, complementary levels — the team is tasked with creating the soundscape of the entire film.

It's up to the sound mixing team, then, to answer some artistic questions with their mix: whether a scene is dialogue- or music-driven; how the music should transition from one scene to the next; how to use sound to evoke emotions the director wants to convey.

Experienced mixers like Michael Semanick often know how a movie is going to sound before they start, particularly when working with directors with whom they've worked previously. "You get a feel of how [the director] wants the film to be," Semanick told me.

It's all about balancing.

Balance

When it comes to what makes a "good" sound mix, Semanick told me that "it's all about balancing" and progressive storytelling.

He explained that a balanced mix should not assault the viewer, and the elements comprising the mix (dialogue, music, and effects) should work together rather than against one another.

The audience needs to be able to follow along, and balancing the components of the mix allows the viewer to feel comfortable. To understand the role of balance, it's helpful to look at a scene where the mix has been purposefully thrown out of balance, a scene from Twin Peaks: Fire Walk With Me, where Semanick says he "want[ed] the audience to be confused."

For this club scene from the movie (video NSFW), David Lynch, the movie's director, kept asking for the music to be pushed louder and louder in the mix until the dialogue was completely inaudible — because, well, that's what it's like when you're in a dark, loud club: disorienting.

Throwing off the normal audio balance is not always a mistake, then. Among the 2015 nominees, the sound mixing for Interstellar is perhaps the most divisive, with dialogue that is often drowned out by music and sound effects. But considering the context – man, insignificant, venturing into the vast expanses of space and time – the decision to put the human voice near the bottom of the sound mix is not an unreasonable artistic choice.

For the most part, though, the focus on achieving the right balance is a large part of why high-quality sound mixing is not usually noticed by casual viewers — good sound mixing, by its very nature, should be unobtrusive. According to Semanick, as soon as the audience notices something slightly off in the mix, "you've lost them — they're not paying attention to your story." Even as an audio expert himself, Semanick finds that he doesn't notice a sound mix when it is well-balanced.

Symphonic Progression

Semanick aims to produce sound mixes that are dynamic and "symphonic," featuring lulls and crescendos that play off one another, driving the story forward.

For "movies that are roller-coaster rides," the sound mix should reflect that, using quiet stretches to emphasize the loud scenes — that is, dynamics — so that the scenes that are supposed to be noisy and exciting don't have to injure anyone's eardrums to make their point.

"Movies that are roller-coaster rides" should feel like it, sonically.

Those dynamics should be calibrated to push the story forward "symphonically," according to Semanick. If you've listened to a symphony, this should be a familiar concept: you'll notice how the dynamics of the instrumentation and the transitions between movements work together to tell an unspoken story. In film, that story is partially explained through the dialogue and visuals, but the sound mix is tasked with completing the narrative.

Semanick noted that among the 2015 nominees, he found Unbroken to be particularly impressive in its symphonic quality. While the opening scene – an air battle – is a fine example of balanced sound mixing in a single scene, Semanick said that it also works as a key element in the narrative arc, the film's sound mix mirroring the physical and emotional descent of American soldier Louis Zamperini as he endures the horrors of life in prison camps.

The climax – when Zamperini and his fellow prisoners are liberated – features the crescendo one might expect in a triumphant moment, but fittingly, given all Zamperini has endured, it is still somewhat muted relative to the bombast of the opening scene.

Sometimes … the sound pushes an audience and they don't know why.

If you're watching any of the Oscar nominees for the first time, we'd suggest not watching with a specific focus on the sound. As Semanick pointed out, sound mixing is primarily noticeable when something has gone wrong, and good sound mixing should seamlessly draw you into the narrative, and it's tough to get that effect if you're artificially focused on the film's sound.

If you're on your second viewing, though, keep an eye (well, an ear) on the sound. Is the music drawing you into the next scene, telling the same story as the visuals and the narrative? Can you hear the dialogue, particularly in complexly shot scenes? And if you can't – if the mix seems to "push an audience away," as Semanick put it – is there an artistic reason for that (as in Interstellar) or was it just poorly recorded and mixed?

And if, even then, you're not noticing much about the sound, it's not your fault — the sound mixing team just did their job well.