Directional mic with heart-shaped pickup pattern — strong front pickup, weaker sides, minimal rear. Workhorse for dialogue and speech on set.
The heart-shaped pickup pattern makes this microphone the most reliable weapon on set for dialogue. You position it just outside the frame, preferably from above towards the actor's mouth-nose area, and achieve a clean, direct voice recording – while effectively suppressing ambient noise from the rear and sides. This isn't by chance, but physics: the cardioid shape is created by combining multiple diaphragm openings that cancel out low-frequency rear noise. A camera running from behind, or grips working nearby – you won't hear it in the recording.
In practice, the cardioid microphone sits on a boom pole, mounted on a shock mount with a windscreen (this is damn important). The directional pattern isn't absolute, but relative to frequency: low frequencies are always captured less directionally than mid and high frequencies. This means that low-frequency machine noise or traffic rumble can still creep into your signal – a high-pass filter on the mixer or correct microphone positioning helps here. The minimum distance to the source should not be less than 20–40 cm, otherwise you'll get the proximity effect: the bass emphasis increases dramatically, and the dialogue sounds boomy.
Do not underestimate how sensitive these microphones are to handling noise. A wobbly boom pole transmits directly as rumble. A firm, precise hold is not optional. The direction perpendicular to the diaphragm is also critical – if you turn the microphone 180 degrees backward, the sensitivity drops dramatically. We consciously use this to isolate unwanted sources or capture multiple actors simultaneously without placing all three on the same boom spot. A standard large-diaphragm cardioid microphone (e.g., from the Sennheiser MKE 600 or Rode NT1 type) is the basic equipment for any shoot with dialogue.
The boundary to the supercardioid and hypercardioid is fluid: these narrower variants deliver even more strictly directional recordings but require even more skill in placement. For fast-paced shoots and changing positions, the classic cardioid remains the safe choice.