Adding A Ld-1A/Ld-2 Line Driver - Meyer Sound MILO Operating Instructions Manual

towards the stage to keep them in phase at both the mix
position and throughout the total array coverage.
Similarly, when M3D-Subs are stacked on the floor below
your MILO array, they may be several feet closer than the
MILO array through most of the coverage, keeping them in
phase (provided the distance is 4 feet or less with the M3D-
Subs being closer).
NOTE: There is no polarity switch on either
the MILO or the M3D-Sub; both are wired pin
2 "hot" (positive acoustic pressure when a positive
pulse is applied to pin 2), making their integration
when co-planar - and in close-proximity – easier
when flown or stacked in the same array.
NOTE:
When both a MILO loudspeaker and
an M3D-Sub are used in their full-range
configuration (e.g. looped audio or the same audio
feed), their polarities should be kept the same if
they are co-planar or near each other. If they are
separated by a greater distance – or delay must be
used between them – a measurement system such
as SIM should be used to determine the correct
delay and polarity.
CAUTION:
When daisy-chaining, make
!
sure that the source devices can drive the
total load of the paralleled array. (See Audio Input
section, page 9)

Adding a LD-1A/LD-2 Line Driver

Driving MILO loudspeakers and M3D-Subs with the same
signal from different outputs using a line driver allows
adjustments to the gain of each sub-system, and could be
used effectively to compensate for the ratio of loudspeakers
or acoustical conditions. If the gains are adjusted to the
same level, the combined response is identical to a daisy-
chain configuration.
Using the LD-1A or LD-2's Lo-Cut filter optimizes MILO's
headroom and reduces the area of overlap; the MILO
loudspeakers in the array receive their signal following a
high-pass filter, while the M3D-Subs apply their normal
internal crossover frequencies to a full range signal. This
configuration results in a smooth frequency response
through crossover and reduces the overlap frequency range
between the loudspeakers.
To drive MILO loudspeakers from the Mid-High output of
an LD-1A line driver (Figure 4.5) or LD-2 line driver (Figure
4.6), engage the Lo-Cut filter with no polarity reversal on the
M3D-Sub's output when co-planar and in close-proximity.
Since an M3D-Sub rolls off rapidly after 80 Hz, there is no
need to engage the polarity reversal on the sub's output.
Figure 4.5: The LD-1A line driver
Figure 4.6: The LD-2 line driver
M3D-Subs should be kept as close as possible to your
MILO loudspeakers to avoid phase errors and cancellation
in some seating locations. If M3D-Subs and MILO
loudspeakers are flown side-by-side, they should not be
separated by more than 3 feet.
NOTE: Placing the M3D-Subs more than 4
feet away from your MILO array may require
setting M3D-Subs/MILO loudspeakers to opposite
polarities.
With a 2:1 ratio, an M3D-Sub produces roughly 3-6 dB rise
below 100 Hz, which is often desirable. The LD-1A or LD-2
Lo-Cut Filter keeps the build-up of energy from 100-200
Hz to a minimum, resulting in the smoothest frequency
response you can achieve for an M3D-Sub/MILO combined
configuration.
NOTE:
When driving MILO loudspeakers
from the Mid-Hi output of the LD-1A or LD-2
line driver, with the Lo-Cut filter engaged and the
M3D-Subs in their full-range configuration, their
polarities should be kept the same if they are co-
planar or near each other. If they are separated by a
greater distance – or delay must be used between
them – a measurement system such as SIM should
be used to determine the correct delay and polarity.
CHAPTER 4
19