HK Audio CDR 210 F - Manual (Page 32)

Manual
COHEDRA
® & COHEDRA ® Compact
Figure 21: Groundstack with CDR 210 F Sub
and CDR 208 S/T enclosures
10 Ground Stacking
10.1 Ground Stacking with
the Stack Frame
The stack frame was developed especially for
ground-stacking CDR 208 S/T and CDR 210 F Sub
enclosures. If you are unable to fly the top units or
bass bins, the stack frame provides the underpinning
for setting up stacked mid/high arrays or a fullrange
stacks comprised of CDR 210 F subwoofers and
CDR 210 S/T mid/high units.
The stack frame is equipped with four extendible,
height-adjustable feet. This lets you adjust the
stack to suit the underlying surface. In addition,
the feet are infinitely variable, allowing you tilt the
entire stack forward or back to align the system to
the audience. The stack frame is readily set up and
stowed away in a case. Its removable feet facilitate
handling and transport.
Technical data (preliminary):
Weight: approx. 30 kg / 66 lbs
Base dimensions (with feet fully extended):
approx. 200 cm x 160 cm
Dimensions (dismantled):
approx. 80 cm x 80 cm x 40 cm
Material: Steel w. black enamel coating
10.2 Ground Stacking with
the Rigging Frame
This option is recommended for smaller (four mid/
high units) configurations in venues that do not
allow enclosures to be flown, or when you want to
cover galleries, terraces or balconies.
Place the top rigging frame on the ground or stage
without shackles so that the connector components
for the mid/high enclosures face up. If necessary,
place wooden wedges under the rigging frame to
ensure a stable, secure and level position.
Remove all three pins from the rigging frame and
mount the mid/high enclosures one after another.
The procedure is the same as for a flown system,
apart from the fact that enclosures are stacked upside
down and, due to the weight of the enclosures, a
lashing strap is not required for curving purposes.
Caution: Always secure ground stacks with a
suitable lashing strap to prevent slippage!
11 Setting up Subwoofers
11.1 Sub Array
In a sub array, individual subwoofers are arranged
side by side. This configuration creates a horizontal
cylindrical wave that makes use of the floor contact.
Space two CDR 210 Sub bins about 0.60 m apart.
Spacing them at distances greater than 0.60 m, lo-
wers the sub array's upper frequency limit. This can
be advantageous when you are consciously aiming
to thin out the 100-to-150 Hz frequency range.
Advantages:
A cylindrical wave loses just 3 dB over twice a given
distance, while a spherical wave loses 6 dB, suffering
twice the loss of effective sound pressure.
A cylindrical wave yields the most uniform low fre-
quency diffusion (comb filtering is not a problem).
Disadvantages:
The bass floor array's vertical angle of projection
is 0° in its near field. In practice, this means you
must ensure that the signal is also projected to the
targeted area on the horizontal plane (that is, to the
right and left). To do this, you may have to add bass
bins to the right and left of the array.
Alternatively, you can spread the cylindrical wave
somewhat by delaying the outside subwoofers (for
example, by using a DFC Sub only rack).
Figure 22: CDR 210 sub array
Figure 23: CDR 210 sub cluster