Headroom

Record so the loudest moments sit well below the ceiling. Digital audio has a hard limit at zero. Anything reaching it stops getting louder and starts distorting, and that distortion cannot be undone afterwards. Leaving headroom means putting your normal speaking level somewhere around minus twelve, so a laugh, a cough or a sudden emphasis has somewhere to go. The instinct that causes the damage is recording as hot as possible for a strong signal, when quiet audio can be lifted later at the price of a little noise and clipped audio is gone for good. The same word appears in framing, where it means the space above a subject's head.