Audio Developments AD149 - Manual (Page 27)

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By combining the last two features, AD149 can be configured not only as a four-
output mixer but also as two independently-controlled stereo mixers in the same
chassis.
Unusually for such a mixer, an ‘insert’ switch has been included in the microphone/line
module for use during production. The availability of portable 8-track recorders
enables up to eight microphone signals to be recorded separately, ensuring maximum
flexibility during post-production. However, if the mixer and recorder are
connected via the insert points (send AND return) rather than the channel outputs
(clean feeds), by selecting appropriate insert switches, sample mixes may be
auditioned at the time of production.
For stereo operation, linking bars are available for the faders on adjacent modules -
rendering a stereo-microphone module totally unnecessary.
All existing evidence indicates that a stereo module is an exercise in compromise - a
pair of mono modules with faders ganged for stereo operation will always offer more
versatility and control (but not one-handed operation). Personal experience tells us
that ganged equalisation is rarely what is actually required in the L-R domain, and
is NEVER required in the M-S domain. Ganged equalisation is also, of necessity,
less sophisticated than that which it is possible to include in a mono module.
By omitting unnecessary equalisation, we have been able to make the stereo module
an exercise in NO-compromise. An input-reverse switch allows placement of
an S-signal on the right-hand path without having to replug. The ganged input-gain
control does not have its range restricted, and is followed by a pair of matrix amplifiers
enabling conversion from L-R to M-S and/or M-S to L-R. The matrix amplifiers may
also be used to create a 'Blumlein Loop' in which it is possible to take advantage of all
techniques described by the great man: the right-hand-path phase-change switch
enables L-R orientation to be reversed; the 18dB/octave high-pass filters are
individually selected; the balance control changes width from mono to enhanced
stereo; the insert points enable the engineer to introduce signal-processing
equipment of his choice - FLEX-EQ being the perfect equaliser for shuffling.
Following the stereo fader is another balance control (of restricted range) to steer the
stereo signal to its correct place within the final L-R image.
The right-hand path, or the left-hand path, or a mix of both may be panned between
the left and right outputs from the module. Independently, the auxiliary paths may be
arranged as a stereo pair.
Because of lack of space, no clean feeds are available from the stereo module.
The mono line module is available to engineers who prefer working with two mono
modules rather than a stereo module and has been specifically designed for stereo
operation.