Heart-shaped microphone pickup pattern that captures frontal sound optimally while rejecting side noise by 15–20 dB; standard for dialogue and close-range recording.
Technical Details
Cardioid microphones achieve their directionality by combining the pressure-gradient and pressure-receiver principles in a 1:1 ratio. The polar pattern follows the mathematical formula: Sensitivity = 0.5 × (1 + cos θ), where θ is the angle of incidence. Condenser microphones with a cardioid pattern exhibit frequency responses from 20 Hz to 20 kHz with tolerances of ±2 dB. Dynamic cardioid microphones typically reach 50 Hz to 15 kHz. Variants include the supercardioid with 125° rear rejection and the hypercardioid with 110° for even stronger directionality.
History & Development
In 1928, Georg Neumann developed the first commercial cardioid microphone, the CMV3, by combining two capsules with a 180° phase shift. RCA introduced the 44-A in 1931 as the first ribbon microphone with a cardioid pattern. Shure revolutionized the market for dynamic cardioid microphones in 1965 with the SM57. Digital signal processing has enabled electronically controllable polar patterns since the 1990s, while modern microphones like the Neumann U87 have been switchable between omnidirectional, cardioid, and figure-8 patterns since 1967.
Practical Application in Film
Boom operators use cardioid microphones like the Sennheiser MKH 416 for 90% of all dialogue recordings, as they reduce reflections from walls and ceilings by 15-20 dB. In "No Country for Old Men" (2007), sound designer Skip Lievsay exclusively used cardioid microphones for minimalist dialogue recording. On-set microphones with a cardioid pattern effectively eliminate camera noise, while lavalier microphones with a cardioid pattern, such as the DPA 4061, reduce clothing rustle by 10 dB. The disadvantage is the proximity effect amplification of bass at distances under 30 cm.
Comparison & Alternatives
Omnidirectional microphones offer a more natural sound without the proximity effect but pick up ambient noise equally from all directions. Figure-8 microphones (bidirectional) completely eliminate side interference but require precise positioning. Shotgun microphones with interference tubes achieve higher directionality than hypercardioids but exhibit comb filtering effects in indoor environments. Modern array microphones like the Sennheiser AMBEO VR use multiple cardioid capsules for 360° recordings, while digital beamforming systems replicate cardioid patterns in software.