Sound Editing vs. Sound Mixing: What’s the Difference?

Gorodenkoff/Shutterstock

Sound editing is the postproduction process of assembling, tweaking, creating, and re-recording all of the audio that makes up a film’s sound design. The sound editor is in charge of piecing together all of the sound that accompanies the visual footage—this includes the dialogue captured on set, additional dialogue, sound effects, music, and ambient noise. 

Sound editor Walter Murch (“The Godfather Part II,” “Apocalypse Now”) helped to visualize the job like this: “Imagine a strip of images in one position, and right below that, a strip of sound, which is dialogue, and that exists on its own track. Below that: many dozens—sometimes hundreds—of other tracks made available for different sounds. You can think of it as a kind of mosaic. [We] have to put [the little chips of sounds] in the right place.”

The elements of sound editing include: 

• Dialogue: One of the primary tasks of the sound editor is to sort through and assemble the right dialogue tracks. Dialogue is often captured on set, so this is a matter of properly matching the best snippet to the shots the director chooses. 
• ADR: Automated dialogue replacement (ADR) is the process of re-recording unusable or additional dialogue after filming has wrapped. Once the desired dialogue is recorded, the sound mixer ensures the new sound blends with other elements to create a seamless experience.
• Sound effects: After dialogue, the editor adds the necessary sound effects to enhance the imagery. These are more general noises—often pulled from a library—such as a gunshot, a door closing, or a car engine. 
• Foley: For more specific sound effects, the editor turns to the foley department. Foley artists watch the footage and work to recreate certain sounds in time with the movement—such as footsteps or a hand brushing against a coat. 
• Background ambience: Rain, waves crashing on the shore, or even the low chatter of people in a crowded restaurant adds an immersive layer to a project’s sound design. This occasionally requires field recording, which, as its name suggests, entails going out “into the field” to record natural, ambient noise.
• Music: The final step of sound editing is working closely alongside the composer and music editor to figure out how to integrate the score and soundtrack into the scenes.  

The sound editing process is only concerned with how the audio works in relation to the images onscreen—the timing, the accuracy, and the mood or tone of the piece. Once all of that is assembled and in the right place, the sound editor hands the reins over to the re-record mixer, who balances it all together.

Piotr Piatrouski/Shutterstock

Sound mixing is the process where the raw materials assembled in the sound editing process are combined and balanced into a coherent soundscape. If sound editing is making sure all the sound is available and in the right place, sound mixing is ensuring it all sounds right. 

The elements of sound mixing include: 

• Level adjustment: Balancing and adjusting sound levels is a key component of mixing. The mixer makes sure every audio component in the scene is at the right volume and doesn’t interfere with another. The background noise of a cafe doesn’t drown out the main characters’ dialogue; the score enhances a dramatic moment instead of overwhelming it; the sound of a car’s engine isn’t louder than the conversation taking place in the front seat. 
• Blending frequencies: Sound mixing isn’t just a matter of raising and lowering the volume. Mixers must blend sounds of all different frequencies, which gives the total soundscape a natural, harmonious depth. 
• Adding effects to audio: During the sound editing process, a lot of the assembled effects are raw and untouched. Sound mixers can add audio effects to make them feel natural within the scene’s environments. Adding reverb to footsteps, for example, blends them seamlessly into a scene set in an echoey hallway.
• Mixing in stereo: One of the more complex parts of sound mixing is placing audio at its proper “width” or “depth.” For example, the sound of a distant storm should feel further away, or deeper into the frame, than the sound of a match being lit in a close-up shot. This process often involves panning, or ensuring a sound travels naturally from one side of the frame to the other to match movement.