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Unpack the 8256X cabinet. This cabi
net is seaied at the factory; do not
attempt to take it apart or remove the
back panei.
Turn the cabinet so the short side with
out fibergiass lining is up; drill a hole in
the top, avoiding the diagnonai brace.
This hoie shouid be just large enough
to pass four wires through.
Do not drili this hole if the loud
NOTE ■
speaker is to be instailed behind
the screen in a motion picture
theatre.
3. The interconnecting wires are packed
Locate the four iongest wires (one red
wire, one green wire, two biack wires).
4. Unpack the two 3156 LF ioudspeakers.
Attach a green and biack wire to the
terminals of one loudspeaker. See
Figure 2.
5. Lay the 8256X cabinet on its back
panel. Mount one 3156 loudspeaker in
one baffie opening of the cabinet;
attach the ioudspeaker with eight
screws packed with the loudspeaker.
Note that the flange of the loudspeaker
outside the cabinet, with the frame
is
and magnet structure protruding into
the cabinet.
6. Route the green and biack wires of the
loudspeaker through the opposite baf
fie opening; attach the wires to the
second 3156 loudspeaker. Also attach
red and black wires to the terminals of
the second loudspeaker as shown in
Figure 2. Feed the attached red and
biack wires through the hole drilled in
the top of the cabinet (Step 2) or
through one of the bass refiex ports;
instali the second ioudspeaker in the
remaining baffle opening and secure it
with the eight screws packed with the
loudspeaker.
7. Lift the cabinet upright and place it in
the position it will occupy.
8. Unpack the two brackets and driver
cradle from the hardware kit. Assemble
them with two bolts, two lockwashers
and two 7/16" nuts. See Figure 1. Set
the assembiy on top of the cabinet,
approximateiy centered with the driver
cradle toward the rear of the cabinet.
9. Upack the 288-8K HF driver and the HF
horn (MRil564, MRII594, or MRH5124).
Piace the gasket packed with the
288-8K around its sound exit hole;
install the 288-8K on the horn, securing
it with the three iockwashers and 9/16"
nuts provided.
10. Engage the lip flange of the horn in the
two ears of the mounting brackets and
swing the driver down into the cradie.
------------------- CAUTION
----------------------
The magnet will pull the cradle
toward the driver as it is iowered
into position.
11. Attach the short black and white wires
packed with the N1285-8A network to
the terminals on the 288-8K. It will be
necessary to remove one pair of crimp
A6 SERIES
LOUDSPEAKER SYSTEMS
connectors from these wires and
repiace them with those packed with
the 288-8K.
12. Piace the N1285-8A on top of the cabi
net, facing left or right; if the speaker
wires are routed through a port in the
baffle, put the N1285-8A on the same
side.
13. Set the frequency switch of the N12858A to 500 Hz or 800 Hz. Wire the N12858A according to Figure 2.
14. if the ampiifier to be used cannot
safeiy drive a 5-ohm ioad, wire the sys
tem as shown in Figure 3, using a
15067 autoformer.
15. If you wish to attach the N1285-8A to
the cabinet, let the front panel of the
network hang over the side of the
cabinet; drill or punch twao pilot holes
and install two wood screws to secure
the network.
16. Decide how much power loss is accept-
abie in the line between the ampiifier
and the ioudspeaker; select a wire
gauge according to Altec Lansing
Technical Letter 265A. Attach the
wires to the input terminals of the
N1285-8A network.
17. Adjust the tilt of the HF horn for great
est uniformity of direct sound in the
audience area; ioosen the nuts and
raise or lower the driver cradle as
necessary; retighten nuts.
18. Operate the loudspeaker and adjust
the H.F. LEVEL control on the N12858A until the best spectral balance is
achieved.
19. If there is sufficient front-to-back
ciearance around the ioudspeaker,
adjust phasing of the drivers according
to Aitec Lansing Applications Note 9.
This wili require the front lip of the HF
horn to overhang the front edge of the
cabinet about 7".
20. After locating the horn position, mark
location of the four holes in the mount
ing brackets; drill or punch pilot holes
in the cabinet for the four wood screws
provided in the hardware kit.
21. If it becomes necessary to replace the
diaphragm/voice coil assembly in the
288-8K driver, use a 23763 diaphragm;
follow service instructions in Altec
Lansing publication 42-02-035593.
a MARK IV company
Specificationa and components subject to chanpc without
notice. Overall performance will be maintained or improved.
10500 W, Reno Ave,, Oklahoma City, OK 73126
42-02-035639 • 42-07-035639
LITHO IN U.S.A. 1091-1.7M
ALTEC LANSING CORPORATION
REVISION 2
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22. If it becomes necessary to recone the
3156 loudspeakers, use a R3156 recone
kit; follow service instructions in Altec
Lansing publication 42-02-035594.
23. If it becomes necessary to repair the
8256X cabinet, construction plans are
given in Altec Lansing Applications
Note 12.
Individual copies of this and all
Altec Lansing publications are
available without charge from
Altec Lansing, Box 26105, Okla
homa City, OK 73126-0105.
WHITE
Figure 2. Wiring Diagrams for Four-Ohm Operation
Figure 3. Wiring Diagram with 15067 Autoformer
-2—
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