Shotgun Microphones: Sennheiser Moves the Market

The shotgun microphone is fairly mature by any definition of audio technology, but it grew up quickly. It dates to the 1950s, when it was invented by Harry Olson, a pioneer in the field of acoustical engineering at RCA Victor, and its real genius lies in how it meshes electrical and acoustical principles, using frequency cancelation created by timing differences between the slots in the side of the interference tube to eliminate off-axis sound and allow the microphone capsule at the base of the tube to focus intensely on the source that it’s pointed at.

Once the principle was established, the shotgun has seen constant tweaking, and the mono version that was the category’s foundation has been joined by stereo and, more recently, digital versions of the microphone. The handful of manufacturers who specialize in shotguns revisit them periodically: Audio-Technica has been working on a new iteration for some time, and Sennheiser, the most widely known company in the category (the company unveiled the MD 82 in 1956, the first commercial mic using the interference-tube principle), brought out its latest two years ago.

Sennheiser’s MKH 8060 (short) and MKH 8070 (long) shotguns are the successors to the venerable 416 model that’s part of the standard complement of every remote truck in North America, and the 816, which is no longer manufactured because of a lack of certain key components, according to Joe Ciaudelli, director, advanced projects and engineering services, Sennheiser.

The MKH 8060 and MKH 8070 use Sennheiser’s radio-frequency design, in which a high-frequency (about 8-MHz) RF signal is applied to the mic capsule; sound waves move the super-sensitive mic diaphragm, modulating that RF frequency, which is then rectified to become an analog waveform. A significant advantage of this approach over traditional condenser-microphone transducers is that the RF design can operate in extreme temperatures and humidity, where other condenser mics would become unusable. Small wonder sports-broadcast engineers have embraced it.

The mics also reflect modern manufacturing and design techniques: they’re lighter and intended to accommodate the growth in handheld cameras, and a new feature is Sennheiser’s MZD 8000 digital module, a screw-on analog-digital converter that replaces the analog XLR output with an AES-42 digital output. The MZD 8000 connects to any AES-42–compatible recorder/mixer.

“The 416 is our classic shotgun, but the new ones have new design features, like symmetrical capsule design, with a diaphragm between two charged plates, which keeps overall impedance constant and reduces distortion,” Ciaudelli explains. “The modular connector lets them connect directly to an AES-42 device, like Sound Devices’ field recorders. But the 8070 reflects increased demand by A1s for a long shotgun that’s extremely directional, to really home in on sound effects.”

Sennheiser also gave its shotgun collection its own power packs last year. The K6’s powering module can be powered either by its internal AA 1.5-V battery or by 12- to 48-V phantom power. The K6 can be combined with different condenser microphone heads to provide a variety of polar patterns.