The SoundField SPS422B
Issue 1.7
User Guide
Page 4
The SPS422B microphone system is based around the same capsule geometry and matrixing
principles as the SoundField MKV but the operation has been greatly simplified by linking all the
capsule matrixing parameters to just two main controls;
Pattern
and
Width
. The result is a single
microphone that can produce optimal results in any situation, mono, stereo or surround but without
the technical complexity of the SoundField MKV. Indeed, the SPS422B is as easy to use as
conventional studio microphones and has the added benefit of remote pattern and width control
allowing the engineer to make most of the critical adjustments while monitoring the result in the
control room.
The SPS422B is designed to function as either a variable pattern single (mono) microphone, a
variable pattern, variable width, coincident stereo microphone array or for recording full surround
sound when used in conjunction with the SP451 Surround Processor or Surround Zone software.
This is achieved using four sub-cardioid capsules set in a regular tetrahedron, and by adding or
subtracting the outputs from these four capsules in different proportions, it is possible to emulate
all possible polar patterns from figure-of-eight through to omni.
Because it is not physically possible to position four separate capsules in the same space, additional
compensation circuitry is employed so that the microphone appears to operate at a single point
located at the centre of the array. A further benefit of this method of matrixing is that a degree of
capsule error cancellation takes place, further improving the performance of these already superb
capsules. The practical outcome of this approach to microphone design is the reproduction of a
soundfield with a far greater sense of perspective and presence than is possible using conventional
microphones.
All the variable parameters may be remotely controlled from the included 1U mains powered
control unit and the phase coherent nature of the system ensures absolute phase integrity in mono
or mono-compatible applications. A key feature of this microphone system is its high degree of
accuracy and its unrivalled ability to capture spatial information. Low noise, proprietary circuitry is
used within the control unit and the line level XLR audio outputs are fully balanced.
Both end-fire or side-fire modes are facilitated and the output signals are available in either LEFT/
RIGHT (XY), M/S (Mid and Side) or four channel SoundField B-Format (W, X, Y, & Z). A high
resolution bargraph metering system provides an accurate level readout of the LEFT/RIGHT
signals and of the M/S signals when in M/S mode. For mono and stereo recording applications the
engineer will make use of the LEFT/RIGHT output; however, the M/S facility is available for users
requiring this specialised facility. Because of the unique single point geometry of the SPS422B, the
LEFT/RIGHT output is exactly equivalent to the decoded M/S output which means there is no
benefit in using M/S mode unless you have a need to vary the stereo width during post production.
For more details on M/S recording see the M/S section of this manual.
For surround recording applications the engineer should use the four B-Format outputs. These
contain the three dimensional information (Height, Width, Depth and Sub Bass LFE) required for
all current and future surround sound formats. The B-Format signals can be decoded into surround
by either the Surround Zone software or the hardware SP451 Surround Processor, both of which
output 6 discrete channels (Left, Centre, Right, Surround Left, Surround Right and Sub Bass). The
Surround Zone software also provides full stereo re-mixing enabling adjustment of polar patterns,
stereo width and all other microphone parameters.
A single lightweight multiway cable is used to connect the microphone to the control unit which as
well as carrying the individual capsule signals also supplies the necessary power to the microphone
allowing unrestricted use in ENG and OB applications as well as in the studio. Various lengths of
microphone cables are available both on and off the drum. Please see the accessories list at the end
of this manual.
INTRODUCTION
