Proximity Effect

Directional microphones, meaning cardioid and figure-of-eight patterns, work by comparing pressure at the front and back of the capsule, and that comparison exaggerates low frequencies as the source gets closer. Omnidirectional mics do not do it at all. Radio voices are built on the effect: get close to a large diaphragm and your voice gains weight it never has in the room.

The problem is the accidental version. Leaning in and out of a mic gives you a voice that pumps between boomy and thin across one sentence, which compression will not clean up. Set a distance, hold it, and high-pass the rest.