SoundField ST450 User Guide
Introduction Page 5
INTRODUCTION
The ST450 Portable Microphone System has been specifically developed for location recording and
in the design process both the microphone and control unit have been considerably ‘downsized’ in
comparison to all other previously available SoundField models. The ST450 simultaneously
provides both surround and stereo soundscapes and its big advantage over alternative methods is
that the multi-channel audio it generates from a ‘single point’ source is completely phase coherent.
This enables the recordist to collapse the surround to stereo or mono without loss of information,
frequency imbalance or any of the other phase problems associated with spaced microphones or
multi capsule ‘dummy head’ arrangements.
The ST450 can be powered by either battery or mains electricity and the microphone can be used at
close quarters on a hand held boom or alternatively situated up to 200 metres from the control unit
on the relevant SoundField mic extension cables (see accessories on pages 25-26). The ability to
adjust all microphone parameters remotely from such a long distance is invaluable in situations
where the microphone is placed in an area which is difficult to access.
The ST450 is connected to the control unit by a single lightweight multiway cable which delivers
the four individual capsule signals to the control unit and carries the necessary power back to the
microphone. A small heating element is located in the microphone head to keep the capsules
condensation-free under normal operating conditions. The ST450 control unit outputs stereo
Left/Right, M/S and four channels of SoundField B-Format called W, X, Y and Z which is the
surround information. All outputs are at balanced line level.
The ST450 is designed to function as either a variable pattern single (mono) microphone, a variable
pattern, variable width, coincident stereo microphone array or to generate full surround from the
four B-Format outputs which will then be decoded into 5.1 by the Surround Zone post-production
software, DSF-3 Digital Surround Processor or analogue SP451 Surround Processor. 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 derive all possible
polar patterns from omni, through cardioids to figure-of-eights.
For surround sound recording the recordist should use the four B-Format output signals. These
contain the three dimensional information (Height, Width, Depth) required for all current and future
surround sound formats. The B-Format signals can be de-coded into surround by the Surround
Zone post-production software, which outputs six discrete channels (Left, Centre, Right, Surround
Left, Surround Right and Sub Bass). The Surround Zone software also provides full surround and
stereo re-mixing enabling adjustment of Polar Patterns, End-fire or Side Address pick-up, Width,
Rotate, Tilt, Zoom and all other microphone parameters. The B-format signals can also be decoded
into surround with the hardware digital DSF-3 1U processor and the analogue SP451 1U processor.
Please note: To maintain a high quality audio performance the ST450 microphone employs studio
grade condensor capsules - in environments of high moisture and humidity (or other extreme
weather conditions) their performance may be temporarily affected.
