MACKIE SP400C - Manual (Page 4)

SP400C – 4
6. Installing the SP400C
The SP400C can be installed into suspended or
drywall-based ceilings. The speaker is secured in
place with the four rotating mounting tabs. The
support rails are used with suspended ceilings
(standard 24" spacing) to transfer the weight of the
speaker to the T-channel runners.
Placement
There are two considerations when deciding
where to place the SP400C speakers.
Location: When installing the speaker in a
suspended ceiling with conventional ceiling tiles,
the location of the speaker is determined in
part by the support grid of the suspended ceiling
system.
When installing the speaker in a drywall ceiling,
the location of the speaker is determined in part
by the location of the ceiling joists.
Coverage: It is important to locate the speakers
in such a way that the sound is evenly distributed
over the entire area. Keep in mind that the sound has
farther to travel on the outside edge of the coverage
area for each individual speaker than directly below
the speaker, resulting in a decrease in SPL at the
outer edges of the listening plane. The SP400C is
–6 dB at an off-axis angle of 55º from 1 kHz to 6 kHz
(110º coverage).
The speaker placement should be designed such
that the edges of the coverage pattern for each
speaker are at least touching. The more overlap that
is provided (higher density coverage), the more SPL
the system is capable of providing and the less
variation in level as you move around the area. The
downside of higher density coverage, of course, is
that more speakers are required for a given area.
Installation
Note: Observe all local and national codes when
installing the SP400C.
1. Cut the hole for the speaker using the supplied
cutout template. If using a circular cutter, set the
diameter to 10.8 inches (274 mm).
2. Insert the C-ring (2) through the hole so the
hanging brackets on the C-ring point up. If
installing in a suspended ceiling, align the
support rails (3) on either side of the hole and
hook them onto the T-channel runners in the
suspended ceiling support grid. Then slide the
C-ring brackets over the support rails as shown
in the illustration below.
3. You can install the SP400C speakers using either
conduit or plenum-approved jacketed cable.
A. Installation with Plenum-Approved Jacketed
Cable or Flexible Conduit
Note: If you can access the back of the SP400C
once it is mounted, you may prefer to do steps A3
and A4 before doing steps A1 and A2.
A1. Attach the speaker cable to the supplied
Phoenix-type connector (8). This is a 4-position
connector, with two "+" and two "–" terminals.
Connect the speaker cable to the "+" and "–"
terminals labeled IN. If connecting another
speaker in a distributed system (in parallel),
connect the speaker cable running to the next
speaker to the "+" and "–" terminals labeled
LOOP THRU.
A2.Open the terminal cover plate (7) on the back of
the SP400C. Route the speaker cable through
the strain relief bracket (9), and connect the
Support Rails
C-Ring
Bracket
Ceiling Tile
T-Channels
1
2
3
4
+ LOOP
THRU
LOOP THRU
IN
IN
+
–
–
IN
+ IN
– LO
OP
THRU –
LO
OP
THRU +