Animators and artists spend significant amounts of time studying physiology, human emotions, body language and the like. We are interested in the mechanics of the human as a machine and emotive force. So when we discuss pulmonary subjects like tidal volume and minute volume we should take note of what they are and how they should influence our animation decisions.

Tidal volume is the measurement of the amount of air that fills the lung in normal breathing. The average tidal volume of air in an average lung is 0.5 liters of air.  This is enough air to service our most basic non-strenuous functions of walking, working, eating, conversing, etc. Minute volume is the measurement of the amount of air inhaled or exhaled per minute.

As animators we don’t need to know anything about these other than that they exist.  They are measurements of our breathing. I would like to use these measurements to help us think about the difference between speaking and singing, dialog and song.

The tidal volume used in simple relaxed dialog will only require half a liter of air.  If a vocalist fills their lungs close to capacity before singing a line of music they will fill their lungs with 4 to 6 liters of air. That’s 8 to 12 times the capacity required for simple dialog. What this means for lip syncing dialog versus lip syncing song is dramatic.

We have to think of our “sing-syncing” as controlled movements of air. The light airflow in relaxed dialog has one effect on mouth and lip shapes. Heavy and intense airflow will have a different effect on mouth and lip shapes. We will consider some of these later. But for now let’s just consider the difference in breath and airflow.

This is conversational speech – less than 1 liter of air — close to tidal volume.

This is intense singing – 4 to 6 liters of air – far beyond tidal volume.

When animating, we want our characters to fill their lungs beyond tidal volume (the inhale) and expend the air in a controlled release of high minute volume (exhale.) The impression of air flow will give us sing-sync. Be conscious of your characters lungs.