The front and rear channels result from the sum (front) and difference (rear) of the omnidirectional and figure-8 microphones on each side respectively (see illustration on the next page). The four resulting “virtual microphones” which this process creates will seem to be aimed forward and backward, as the figure-8s are. At higher frequencies, however, they will seem to be aimed further outward. Their directional pattern can be varied anywhere from omnidirectional to cardioid to figure-8; the pattern of the two rear-facing virtual microphones can be different from that of the two forward-facing ones. Altering the directional patterns alters the sound as well, in ways that are not possible with ordinary equalizers. This permits a flexible means of adapting to a recording situation – to the acoustic conditions in the recording space – and this can even be done during post-production if the unprocessed microphone signals are recorded.


The signals from the four “virtual microphones“ comprise a type of surround reproduction which is valid in its own terms but lacks the center channel and low-frequency channel of the standard 5.1 approach, so these additional facilities are provided by the digital signal processor.

The complete KFM surround set consists of:

• KFM 360 sphere microphone
  
• 1 × KG ball-and-socket joint for mounting on a stand
  
• 2 × CCM 8 L compact microphone (as a matched pair); included: K 5 LU adapter cable (Lemo / XLR-3M), SGC stand mount with swivel and a polished wood case
  
• 2 × SGC-KFM mounting clamp for CCM 8
  
• 1 × DSP-4 KFM processor with mains cable and wood case
  
• 3 × AK SU/2U adapter cable (XLR-5F to 2 × XLR-3M) for connecting the processor’s analog outputs
  
• 1 × KS 5U stereo cable for connecting the KFM 360 (5 m long; advantage: only one cable is necessary for two channels)
  
• 1 × KLY 250/5 SU, Y-cable, 5 m long, for connecting the two CCM 8 to the processor

Available separately:
for the KS 5 U and KLY 250/5 SU cables: extension cables (e.g. KS 10 U, 10 m; KS 20 U, 20 m)
for the KFM 360: KKFM wood case and HKFM suspension device.

When a KFM 360 is ordered separately, it comes with

• 1 × KG,
• 2 × SGC-KFM,
• 1 × AK SU/2U (XLR-5F / 2 × XLR-3M)