SCHOEPS
KFM 6 SPHERE MICROPHONE

• novel, head-related stereo main (not binaural) microphone for loudspeaker reproduction
• very good imaging and sense of depth; good localization, very natural sound
• with qualities similar to those of a dummy head when headphones are used for listening
• superior low-frequency performance
• universal phantom powering from 12V-48V

Stereo main microphones are distinguished by the simplicity of the recording technique and of the setup: Only two capsules and recording tracks are required, and with the KFM 6 only one 2-channel microphone cable is needed. With the sphere microphone the interaural differences are similar to those occurring at the human head. This explains why a sound image quite similar to that for a listener at the microphone position is obtained, with the room (ambience) included.

Limitations of the KFM 6: The recording room should have a good sound, and the recording angle (range within which the sound sources are positioned accurately when reproduced, as viewed from the microphone) is restricted to ca. 90°.

The KFM 6 sphere microphone is the embodiment of a newly-developed stereo main-microphone design using an acoustic baffle. "Dummy-head" systems are well-known for the excellent results they can provide, but the recordings made with such systems are normally suitable only for headphone listening. The "Sphere Microphone" was developed so that comparable results could be achieved for loudspeaker playback.

Such a microphone would not only provide interaural time-arrival cues, but also spectral-vs-angular incidence information. A further requirement was that the frequency response on the main axis of the microphone remain flat in both the free and the diffuse soundfields.

In the construction of the KFM 6 two special pressure transducers are mounted flush on the surface of a sphere 20 cm in diameter, an acoustic baffle having especially favourable properties. Normally two omnidirectional capsules placed so close to each other would not provide a convincing stereo image. However, the sphere between the capsules creates a frequency-dependent emphasis of intensity differences comparable to that naturally occurring at the ears of a human head.

The frequency response on the stereo main axis of the KFM 6 is flat when measured at the output of either channel. If a sound source moves around the sphere, the intensity in the one channel will increase by the same amount as it decreases in the other. This is brought about by the unique construction of the microphone capsules, the effect of the sphere as an acoustic baffle, and some special electronic circuitry built into the amplifier. As a result, the sum of the energy from the two channels is largely independent of the angle of sound incidence, with its frequency response essentially the same for both the direct and the reverberant soundfields.

These features, combined with exceptional linearity that extends to the very lowest frequencies, are responsible for the remarkably natural impression of space, depth, and image typical of the KFM 6.

Additional Information:

• The stereo pickup angle is about 90°.

• A LED pinpoints the stereo main axis. This is especially useful when the KFM 6 is positioned at some distance.

• The sensitivity of the KFM 6 is about 15-20 dB higher than that of a standard Colette Series microphone.

• The KFM 6 can operate into unbalanced inputs without any loss of level and without transformers. This requires a powering device with DC decoupling.

• Any standardized phantom-powering from 12V-48V is suitable. Please note: When 12V phantom-powering is used, the maximum SPL is reduced by 7 dB.

• In order to assure proper operation, make sure that both channels are powered simultaneously at all times.

KFM 6 ACCESSORIES

Included:

• HKFM, a universal device for suspending the KFM 6 on the cable and lines

• KG, ball-and-socket joint for mounting the KFM 6 on a stand

• AKSU/2U, adapter cable (XLR-5F to 2x XLR-3M)

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