Broadcast Engineering      December 11, 2009

KMF Audio miking system offers natural stereo soundfield
by Jack Kontney

The KMF Audio stereo miking system offers a stunning 3D soundstage in a deceptively straightforward design.

Introduced to the audio industry in prototype for in 2008, the stereo miking system developed by KMF Audio has now reached the market in "finished goods" form. The system, available with either tube or condenser elements, employs a pair of matched microphone elements in combination with a custom preamplifier and power supply. The mic elements are suspended at a fixed width in the system such that, when properly positioned within the recording space, the system captures an extremely lifelike reproduction of the listening experience.

KMF was co-founded by inventor and chief technology officer Kent Fuqua and CEO Daniel Atkinson, who has a background in broadcast production and concert promotion. Fuqua has worked in audio equipment design and recording for nearly 30 years. In an exclusive interview, Atkinson related the company's journey from concept to product.

"The aim of the technology is somewhat similar to a binaural technique," Atkinson said. "It preserves phase-angle information so you get a sense of natural human hearing. So basically, the concept is, we have two omnidirectional capsules in a fixed position, which is the distance both between your ears and front to back from the front of your head to your ears. It's attached directly to a custom preamp, so it brings the signal up to line level within inches of the transducers."

As part of the proof of performance for the system, the KMF team recorded an acoustic jazz album called "Standards," with the trio of Peter Erskine on drums, Alan Pasqua on piano and Dave Carpenter on bass, using only two pairs of KMF's stereo tube microphone systems. Inventor Kent Fuqua handled the engineering duties, recording the sessions direct to two-track stereo. Erskine, Pasqua and Daniel Atkinson shared the producer credit.

The album garnered great acclaim among jazz fans, audiophiles and critics for its sound, which gives a definite sense of being at a live concert. Despite being released by a small independent record company (Erskine's Fuzzy Music), the album was honored with a 2008 Grammy nomination for Best Jazz Instrumental Album, Individual or Group. "You certainly couldn't ask for a more definitive proof of concept than that," Atkinson says.

The system uses hand-selected, small-diaphragm, omnidirectional transducers chosen for accuracy. Both the vacuum tube and solid-state versions use and matched custom preamplifier and power supply. Essentially, the only controls involved in using the system are the on/off switch and physically placing the mic in an optimal position. The solid-state version is also available in a battery-powered version, enabling "off the grid" recording for about 10 hours. The tube version uses the latest Russian military-grade vacuum tubes. The overload point for the microphones is about 120dB, easily within the range of most acoustic ensembles. The system boasts a frequency response of 20Hz to greater than 20kHz, with an output impedance of 249Ω. The mic system (with integral preamp) weighs 1.5lbs, while the power supply weighs 4lbs.

"It's really built to cover a huge dynamic range," Atkinson says. "We have a symphony recording that we did with a single mic system. It goes all the way from a single harp to five trombones in the brass section, and you can hear all of them distinctly, and hear exactly where they are on stage. It's really an amazing experience."

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