Lav is a technique of professional sound production.
Technical Details
Modern lavalier systems operate in the UHF range between 470-890 MHz with a transmission power of 10-50 mW. The range is 100-300 meters with a line-of-sight connection. Professional systems like Sennheiser G4 or Lectrosonics achieve a dynamic range of up to 134 dB and signal-to-noise ratios of 110 dB. The battery life of the bodypack is 6-8 hours with AA batteries or lithium-ion rechargeable batteries. Various microphone capsules (omnidirectional, cardioid, or spherical) allow adaptation to specific recording situations.
History & Development
In 1959, Electro-Voice developed the first wireless lavalier system for television productions. Sony launched the first compact system in 1971 with the WRT-27. The breakthrough for film productions came in 1984 with Sennheiser's evolution series, which for the first time ensured reliable transmission even during movement. From the 1990s onwards, digital technology enabled multiple simultaneous channels without interference. Today, systems like Zaxcom TRX900 utilize digital encryption and integrated recording.
Practical Use in Film
In "1917" (2019), Sound Mixer Stuart Wilson used over 20 lavalier channels for the one-shot sequences, as booms were impossible due to the complex camera movements. In action films like "John Wick 3" (2019), waterproof lavaliers ensure continuous audio recording during fight scenes. The standard workflow includes placement on the sternum, under costumes, or on bra straps, with moleskin tape preventing rustling noises. Disadvantages: clothing rustle, sensitivity to sweat, and limited bass frequencies below 100 Hz.
Comparison & Alternatives
Compared to boom microphones, lavaliers offer freedom of movement and a constant microphone position, but poorer sound quality and ambient noise recording. Shotgun microphones surpass lavaliers in directionality and naturalness but are impractical for wide shots. Plant microphones (hidden in the set) eliminate visibility and costume issues but offer less control over levels. Modern alternatives like Tentacle Track E enable 32-bit float recording directly on the bodypack, making clipping impossible and increasing post-production flexibility.