In this clip from the title sequence to Joss Whedon’s 2005 movie “Serenity” I’ve removed the center audio channel. What is left is mainly the ambiences and background effects. After listening to it this way, undistracted by dialog, I have a few observations.
First, and most obviously, this scene would not work at all without sound. There are no windows or portholes or display screens showing us what exists beyond the confines of the ship, so it’s entirely up to sound to convince us we’re in a ship flying through space and not a stationary film set.
Mr. Whedon implements the classic sci-fi trope of creating the illusion of turbulence by timing camera shakes with actors reactions and sound effects. We’ve all seen it a million times (and laughed at it when done poorly) but it still does the trick. Also, at 3 minutes 4 seconds, Mal and the doctor look up in response to an especially loud bang. I wonder what the actors were responding to on set? Probably someone shouting “boom!”. Once again, these are both examples of how sound is used to sell the illusion of a larger reality beyond the frame of the camera. In these examples, the actors interact with the off screen sound which makes the illusion even stronger.
My third observation is not as obvious unless you have worked in audio post. Typically, in scenes with lots of cutting, it’s not uncommon for the perspective of the camera to jump dramatically. Think of your typical conversation between two people facing each other where the camera cuts back and forth from one over the shoulder shot to another, shifting perspective by 180 degrees each time. Now imagine there’s a water fountain or something off to one side. If audio followed the perspective of the camera the sound of that fountain would jump from one side to the other with each cut. With frequent cuts this becomes very distracting so it’s common practice to keep the audio elements more or less stationary, thereby setting up a sort of objective audio perspective separate from the visual perspective. In tracking shots like the one in this sequence, the visual perspective doesn’t jump at all, so it’s possible to lock the visual and audio perpectives more closely together. Pay attention to the use of panning throughout this scene. One good example being the hiss of the engine room as Mal turns to talk to the doctor around 1:41.
My 4th observation is that once the dialog is taken away, and our attention is fully focused on the ambient sounds, they can start to seem over the top and unbelievable. Would a ship solid enough to travel through atmosphere’s really creak and groan like that? It’s very easy to over think every sound, especially during a mix session when scenes are played over and over again. Yet, with the dialog in and our attention focused on what the characters are saying, we accept these sounds as perfectly natural.