Audio Developments AD149 - Manual (Page 21)

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By increasing the S-signal (over the full frequency range), the stereo image of some
recordings can be extended beyond the left and right loudspeakers. This is yet
another of Blumlein's discoveries and contained in the original patent. It is also a very
useful technique for expanding the soundstage of a recording made, for whatever
reason, with a too-narrow stereo image. Results may be dramatic but, equally, they
may be phasey, confusing and unconvincing.
As may be appreciated, shuffling is an extremely versatile technique, but its effects
are largely unpredictable, therefore each recording must be treated on its own merits.
Shuffling, as described, takes place at low frequencies and has no effect at high
frequencies; audible noise is not increased, which is not the case with simple overall
width increase.
If shuffling techniques are to be used during post-production, the monitoring system
must be optimised for precise stereo imaging. This effectively eliminates many of the
loudspeakers used as studio monitors.
MATRIX AMPLIFIER WITH WIDTH AND POSITION CONTROLS, AND SHUFFLER
FIG 3 (b)
M
S
L
R
OUT
IN
+
+
+
-
MATRIX AMP POSITION
(STEER)
SHUFFLER
EQ
EQ
WIDTH
(BALANCE)