The SoundField SPS422B
Issue 1.7
User Guide
Page 13
The SPS422B microphone system and the SP451 processor are very easy to use. The four B-
Format outputs from the microphone system may either be fed directly to the SP451 for 'live'
surround recording or recorded to a multi-track recorder and then played back into the SP451 for
post-production processing. The SP451 uses these signals to create up to three 5.1 surround
microphone arrays.
SURROUND SOUND RECORDING
The five microphones of this virtual array represent the conventional Front mic positions at Left(-
45 degrees), Centre (0 degrees), and Right (+45 degrees); the surround positions are at Rear Left (-
135 degrees) and Rear Right (+135 degrees). The LFE (sub-bass) output is derived from its own
virtual omni microphone.
By processing the B-Format signals via the SP451, the mixing engineer has the ability to create the
optimum surround mic array configuration. Equally important, the same B-Format signals can be
processed in a variety of ways to meet the broad range of needs imposed by differing audio
delivery formats. Thus, a stereo music recording for CD production, a mono feed for AM radio,
and a surround soundtrack for video or DVD all can be created either independently or simultane-
ously. All this can be done either in 'real time' or during any stages of post-production, affording
the mixing engineer the ability to create the ideal sonic perspective under the controlled conditions
of the production studio, rather than forcing a decision during the original recording session that
later may prove to be less than ideal.
In order to avoid the confusion and complexity that could result from an infinitely variable system
(we all are familiar with the 'too many knobs' syndrome) the SP451 processor uses plug-in MAP
(Microphone Array Pattern) cards to define the basic default polar patterns and angles of the virtual
microphone array, and provides the user with just the front panel controls needed to optimise this
initial array for any specific application quickly and easily. For example, the Front and Rear
microphone pairs in a 5.1 array may be adjusted ± 45 degrees from their default angles, to suit any
desired music and/or video reproduction system for surround sound.
All of the outputs are at line level and represent the discrete outputs from the microphones of the
virtual array. No further SoundField processing is required once the signals leave the SP451.
The Rear Focus control enables the polar patterns of the Rear microphone pair to be varied. This
provides significant adjustment of the imaging and 'spaciousness' of the surround channels.
L
R
C
SL
SR
The five cardioid MAP card supplied
as standard with the SP451 Surround
Processor.
