Despite my severe hesitation around recording in stereo (I practically break out in hives thinking about it), I put together the following FAQ for beginners. It’s based on my conversation with former NPR engineer Flawn Williams on this edition of HowSound and my own field recording experiences. This is meant to be a quick and dirty set of guidelines for recording stereo while reporting a story.
What’s the difference between mono and stereo?
In short, a mono recording is one where the sound in the left and right channels is the same. A stereo recording has different sounds in each channel.
Why do I get hives?
Frankly, recording in stereo seems fraught. It’s more complicated. I like to keep my recordings simple and mono is simple.
Two things immediately come to mind. First, you have to take into consideration the directionality of the sound. Let’s say I’m recording in stereo walking on a beach and the ocean waves are to my right. If I turn around and head in the other direction, the waves are now on my left. Now I stop and face the ocean. The waves are in the middle of the stereo field. First right. Then left. Then center. Yeesh. In mono, that’s less of an issue.
And then there’s editing. I don’t want the ocean to drastically change position as I edit. As Flawn says: “Having a mono recording makes it a lot easier to find places where you can unobtrusively jump (edit) from one section of a conversation to another or something like that. But, because of the heightened realism of stereo, any change, abrupt change in the background sound is going to be more noticeable and harder to make unobtrusive, harder to mask than editing the same material would be in mono.”
So, why record in stereo at all?
Flawn said it best during our interview. “I find that listening to sound in the most realistic fashion is the best way to relate to it. And, something that can really put me into a location is something that I really enjoy… It is that sense of immediacy. It is that sense of involvement of the ears. If you listen to something like…a rain forest ambiance or even a temperate forest or a city streetscape…your ears and your brain, translating what your ears are giving it, is going to be much more engaged because you’re paying attention to things in terms of direction as well as loudness and proximity.”
For me, it’s about information. Is there something about the “stereo information” that you want people to hear. Or, will they get the same “info” from a mono recording.
Take a construction site, for instance. If there’s just a couple of people hammering some nails, I’d chose mono. But, if it is a site full of activity and sound is everywhere — hammering, sawing, trucks backing up, people shouting from the roof — AND that commotion is part of the story, then I might decide to record in stereo because I want to communicate more fully the bustle of the workers. Otherwise, I’m going mono.
For recording in stereo, I only have built-in mics. Can I use those?
Maybe. But be VERY careful. Those mics tend to be sensitive to mic handling noise and wind. If you can avoid those problems, then go for it.
Should I record an interview in stereo?
No? Never?? Let’s say I’m stuck. I don’t have an external mono mic with me and really, really need to record an interview.
My first response is always carry a mono mic!
But, if you’re in a pinch… go for it.
Consider trying it this way: Turn your recorder sideways. Face one mic toward the interviewee and one mic toward you.
As always, beware of mic handling, wind, and p-pops. Also, because the recorder is sideways, you may have difficulty reading the meters and adjusting levels.
Later, in your editing software, you’ll probably want to split the recording into two mono-files. More on “split-track” below.
And, a friendly reminder: You still have to get the mic in close. You’ll need to move the recorder back and forth between you and the interviewee to get good sound.
What about recording ambient sound in stereo with my built-in mics?
Ambi is the most obvious sound to record in stereo. My advice is to stand still and point your mic in a single direction. As Flawn suggests in this episode you could also walk slowly through a scene or pan (move) your mic slowly in one direction.
I plan to be moving around a lot while recording. Can I still record in stereo?
It’s not a good idea to move around quickly and aim the mic in several different directions. Or, as Flawn put it “Don’t wildly flail the microphone around.” The sound will move around in the left and right channels and the listener may not know why. It could be more annoying than interesting.
Yup. Pick a nice spot, probably near the front and in the center. Face the mic toward the music and stand still.
There is a lot to consider in terms of how close to get: Do you want to sound like you’re practically on stage? At the back of the hall? How much of the audience do you want in the recording? If you have time, stand in several places so you have choices later on. But, typically, a few rows back and in the center is best.
My recorder has an option to record mono files and stereo files. What’s that all about?
Yikes. I was afraid you were going to ask that.
The short story is this: If you’re making a stereo recording, chose a stereo file. If you’re recording in mono, chose a mono file. (BTW, mono files are about half the size of stereo files.)
To elaborate: A mono file captures the audio in such a way that all the sound you record is the same in both channels. Even if you’re using built-in or external stereo mics, the sound will be mono — the same in both channels.
A stereo file, on the other hand, captures the audio and makes a distinction between what’s intended for the left channel and what’s intended for the right channel. In a manner of speaking, it’s like there are two separate pieces of information in one file.
Is this the part where “split-track” comes in?
Let’s take the interviewing example from above. You don’t have your external mono mic with you and decide to record an interview with built-in stereo mics. One mic faces the interviewer; the other faces the interviewee.
Or, maybe you’ve got a recorder that allows you to plug in two different mics. Again, one faces the interviewer; the other faces the interviewee.
If you chose to record a stereo file, one person will be primarily in the left channel, the other will be primarily in the right.
Even though recording this way in a pinch makes some sense, ultimately, you don’t want people to sound far to the left and far to the right in the final story. You want people to be in the middle — to sound like you’re in mono.
You can fix that problem in your editing software. Chances are, you have an option to “split stereo.” This will take your stereo file and split it in two. In Hindenburg, for instance, the software not only splits the file in two, it gives each channel its own track. That way, you have more control over each element — the interviewer and the interviewee.
Now, if you’re still following me…
You could choose to record a mono file in this interviewing scenario. That way you don’t have to deal with “splitting” the file later on. But here’s a catch — there’s actually a hidden advantage to recording split track: the idea of being able to control each element.
Here’s what I mean: Say someone is giving me an answer while I record them in the left channel and over in the right channel, I squeak my chair. Later, after I split the file in the software, I can delete the squeak. You can still hear the squeak in the other channel, but less so.
Final question: What if I have an external stereo mic?
I think every answer above applies. An advantage to using an external stereo mic is that you can probably put a pistol grip on it in order to isolate mic handling sound.
We’d love to hear more examples, so please share stories produced in stereo — even stories where recording in stereo was a bad idea.
Or, if you have additional stereo recording tips, let us know.
Here’s some more good listening from Flawn about recording howler monkeys in the Amazon.