Tidal Volume and Minute Volume
Your drawing instructor never taught you this
Animated musicals are everywhere these days. Maybe you’ve already worked on one. If not—hang around long enough, and you probably will.
Most of us have spent time poring over George Bridgman’s anatomy books—learning how muscles pull on bones, how tendons limit range of motion, how the body moves like a finely tuned machine. It’s good stuff. But there’s one limitation to Bridgman—he wasn’t thinking about animators. He was talking to painters and illustrators. Painters and illustrators don’t think much about breathing.
But we need to. Every character needs oxygen, especially if we're animating musical performances. Because when someone sings, it’s not just about body mechanics—it’s about airflow—and a lot of it.
There are two key terms worth knowing here: tidal volume and minute volume. Both are measurements of breathing.
Tidal volume is the amount of air that fills the lungs in one breath. For the average person, that’s around 4 to 6 liters.
Minute volume is how much air moves in and out of the lungs per minute. And here’s the interesting part: in normal breathing, the inhale is faster than the exhale.
For basic, everyday stuff—checking your mail, chatting, walking—you only need about half a liter of air.
But if your character sings a lullaby, that tidal volume intake might go up to 2 or 3 liters. If they’re belting out a big, emotional number—think Whitney Houston raising a roof—that’s a full 4 to 6 liters. That’s max capacity.
So what does this mean for animators?
It means that singing exchanges ten times the air of regular dialogue. Ten times the tidal volume. Let that sink in.
Big singing moments demand quick, powerful inhales—squeezed between lyrics and phrases. The exhale, on the other hand, is slower, more controlled. The mouth shapes that air into sounds. That’s why singers’ mouths look so expressive, even strange sometimes. They’re sculpting sound in a rush of air.
Now watch someone fake it—like Milli Vanilli lip-syncing. Their mouths are moving in time, sure, but something feels off. There’s no real air behind it. No pressure. The tidal volume is too low. The minute volume is dead. You may not be able to explain it in technical terms, but you know it isn’t real.
It’s not just about puffing out the chest. When a person sings, the force of that air being pushed across the vocal cords, through the mouth, shapes every part of the performance. You can see it—in the chest, neck, throat, jaw, cheeks, lips, nostrils. Even the eyes. And when it’s big? It affects the entire posture of the body.
So here’s the takeaway: don’t animate a Milli Vanilli performance. Make me feel the airflow. Make me feel the warm air rushing out of their lungs, shaping every frame.
That’s when the performance starts to sing.