Jason setting up a pair of Sennheiser 8040s on Hurricane Ridge, Washington State, USA.
The answer, of course, is “it depends”. Here are a few questions to consider before breaking out the stereo pair:
Is the recording intended to capture movement?
It is perfectly reasonable to record a car pass or a bullet whiz by in stereo. The movement is crucial to the sound and mono would fail to capture the essence of it. Of course, mono sounds can always be panned to approximate that movement.
Is the recording meant to be immersive or evocative of an environment?
Ambience just wouldn’t be ambience without stereo cues. In my opinion, backgrounds should be at least stereo and maybe even surround or immersive.
Is the space surrounding the sound important?
Take gunshots for instance. The sonic effect of the space on the gunshot is exaggerated due to the shear amount of energy exciting the space. It’s immediately apparent if a gunshot was recorded in a small interior, large interior, or exterior. Spatial timing cues really help to put the sound in the right space.
Is the sound larger than life or non-diegetic?
Something like a braam, stinger, riser or jump scare should feel large and powerful. Stereo excels at that.
How wide should the sound really be?
Consider the end user. I frequently mix on a theatrical Dub Stage where the front left and right speakers are about 30 feet apart. Stereo sounds that shouldn’t be in stereo stick out because they feel unnaturally wide and by extension, unnaturally close.
Imagine the sound of a laptop closing (I don’t know…that’s what’s right in front of me). For that sound to justify itself being 30 feet wide at the mix position, the camera angle would need to be an extreme closeup. Let’s do some simple math (the only kind I can do):
The mix position is 40’ away from the speakers, which are 30’ apart from one another. That’s a 1.333:1 ratio. So, if the laptop is one foot wide in real life that means I’d have to have my head 1.333 feet from the laptop to match the same audio perspective. If the image on the screen matches that perspective then it MIGHT make sense for the sound to be in stereo, but even that’s a stretch. Odds are, the perspective on the screen is much wider than that, so the sound should almost certainly be recorded in mono.
Will my recording be mono compatible?
In the above example, I may elect to do one of two things. I could drop a channel (I.e. simply omit either the right or the left channel). Or, I could sum it to mono. Some stereo mic techniques sum to mono reasonably well, XY for example. Others, like spaced pair, may cause problems.
Weird Stereo
Wrapping up
We love stereo! Personally, there’s no mic setup I prefer more than our pair of Schoeps MK41s in ORTF. But, when recording library content not everything should be presented in stereo. Ask yourself these questions. If the sound doesn’t hold up to the scrutiny, mono may be the better option. More channels does not necessarily equal more production value!