A microphone's polar pattern defines how its sensitivity varies with the direction of incoming sound

A polar pattern is a 2-D plot of a microphone’s sensitivity as a function of the angle of the incoming sound at a given frequency. Common patterns: omnidirectional (equal sensitivity from all directions, no proximity effect), cardioid (heart-shaped — most sensitive from front, least from rear), figure-8 (most sensitive from front and rear, rejects sides), supercardioid and hypercardioid (narrower than cardioid, some rear lobe). Directional microphones exhibit the proximity effect: a bass boost when the sound source is very close (within a few inches). Polar patterns are frequency-dependent — a cardioid becomes less directional at low frequencies. Pattern choice affects feedback resistance (cardioids reject stage monitors entering from behind) and isolation between sources.

Examples

Placing a cardioid vocal mic so its rear null points toward the stage monitor gives maximum feedback rejection. At 250 Hz, however, the rear null narrows, so low-frequency monitor bleed still enters.

Assessment

A vocalist moves closer to a cardioid mic. What frequency range is most affected and why? How would you counteract this if the vocals become overly boomy?