Microphone hidden within the set, attached to props or set dressing for discreet, unobtrusive audio capture without visible boom or lav placement.
Technical Details
Plant mics typically use small-diaphragm condenser microphones with a cardioid polar pattern and a frequency response of 20 Hz to 20 kHz. Capsule diameters range from 3-6 mm with a sensitivity of -44 dBV/Pa. Modern systems utilize digital wireless transmission in the 2.4 GHz band with a latency under 2.9 ms. Battery life averages 8-12 hours with lithium-based power cells. Omnidirectional characteristics are often employed to compensate for changes in actor positions.
History & Development
The first plant mics originated in 1952 at Warner Bros. for the television production "Studio One," where technicians hid microphones in table lamps and flower vases. In 1967, Sennheiser developed the first professional plant mic system, the MKE 2, for theater productions. The breakthrough came in 1975 with wireless systems from Sony, which made plant mics practical for film productions. From 1990 onwards, digital transmitters enabled the simultaneous use of up to 32 plant mics without frequency interference.
Practical Application in Film
In "The Social Network" (2010), Ren Klyce used plant mics in computer monitors and desk lamps to naturally capture hectic office conversations. "Birdman" (2014) employed over 20 plant mics in mirrors and lighting fixtures in the theater dressing room. Plant mics are particularly suitable for ensemble scenes with unpredictable movement patterns and improvisations. However, they require precise pre-planning, as repositioning afterward is impossible. Noise from props or electromagnetic interference from set lighting can become problematic.
Comparison & Alternatives
Plant mics differ from lavalier microphones by being object-bound rather than person-bound, and from boom microphones by their static placement. Modern alternatives include array microphones like the Rycote Super-Softie, which digitally combine multiple polar patterns. For mobile camera work, wireless clip-on microphones are suitable, while overhead booms remain more precise for controlled dialogue scenes. Plant mics are optimal for multi-day shoots on the same set with changing camera positions.