MCM Electronics 51-881 User manual

In-Ceiling Speaker
Installation Manual
Model #51-881
MCM an InOne company
650 Congress Park Drive
Centerville, Ohio 45459
www.mcminone.com
© 2003 MCM an InOne company

Single Point Stereo Speaker Systems
The idea behind this is simple. Many rooms
are too small to effectively place a left and
right speaker in the ceiling. This is
especially typical in entryways, guest and
half bathrooms, hallways, closets and
stairways. Initially, the only option was to
squeeze in two speakers, limit sound to one
channel, or deal with a separate mono zone
for those areas.
The answer to this situation is the MCM
Custom Audio model #51-881 Single Point
Stereo Speaker. This innovative concept
includes a dual voice coil 6½" woofer, and
two side-by-side tweeters, each with
independent crossover circuits. To the
audio system, this speaker appears as
independent left and right speakers, yet to
the eye, it is a single speaker.
These speakers may be added to the
distributed audio system with no concerns
for loss of separation throughout the
remainder of the system.
General Features
•6½" polypropylene cone woofer with
rubber surround
•Dual ½" Mylar dome tweeters
•Dual crossovers
•Two pairs of color coded push
terminals
Specifications
•Power Capacity: 25W/60W
RMS/peak per channel
•Frequency Response: 70Hz~20KHz
•Nominal Impedance: 8Ωper
channel
•SPL: 88dB W/M

Installation
Speaker Placement
Careful consideration should be made when determining the desired location of the speaker pair.
As this Model #51-881 is referred to as a ceiling speaker, this is the intended mounting location.
However, there is no electronic or physical reason these cannot be mounted in other locations,
such as walls. However, careful consideration should be given to appearance in these situations.
As noted above, this single speaker provides output for both the left and right channel, so much
greater flexibility is available with regards to proper placement. This speaker may be located
anyplace in a given room, however it is recommended that it not be placed less than 2’ from any
corner. In areas such as hallways, where length exceeds 12’, two speakers should be
considered.
It is important to note that more speakers in a given listening area do not necessarily equate to
higher sound levels. With more speakers, the desired listening level for a given area is attained
with lower output from each speaker. This creates a much more pleasant listening environment
as the sound source can be uniformly heard through the entire room, regardless of location and
with less interference with sounds such as conversation.
Speaker Wire
It is important that good quality wire is used in the installation. Installed speakers generally have
much longer wire runs than normal home theater speakers, hence heavier gauge wire is
recommended. Note: There are numerous manufactures in the market offering “high-end”
esoteric speaker wire, with claims of exotic materials and superior performance. Truthfully, this
type of product has been found to provide little or no benefit to installations of this type. Good
quality 14AWG CL3 rated in-wall wire, such as MCM #24-5790 (two-conductor), #24-5835 (four-
conductor) or similar, provide outstanding performance in this application.
When running this cable, a few simple guidelines must be followed
•All speakers should be home-run. That is, wire should be run directly from each speaker,
back to the sound source
•Speaker wire should be kept away from AC wiring to prevent noise. If AC wiring and
speaker wire must cross paths, it is best to have them cross at a 90º angle, minimizing
the common surface area between the two
•Speaker wire and AC lines should NEVER pass through the same hole in studs or joists
Part 1
New Construction Installation
1. This initial step should be completed after all structure framing is completed, and prior to
drywall installation. In this instance, a Pre-Construction Bracket Kit, such as MCM #50-
6248 (sold separately) must be utilized. These brackets mount to studs or ceiling joists,
and in conjunction with drywall, provide a solid mounting base for the speaker.
Compatible with wood or metal studs spaced at standard 16” centers, the kit also
includes extension rails for ceiling joists mounted on 24” centers.
2. Centering the speaker opening between the studs, mount the Pre-Construction Bracket
to the studs.
3. When running wire to the speaker, leave enough wire length at the speaker end to reach
from the ceiling to almost the floor. This greatly adds safety, as the speaker may then be
connected to the wire while standing on the floor instead on top of a ladder. Coil the
speaker wire and staple to the side of the stud above the bracket. Take care to ensure
that it does not interfere with drywall installation.

4. Once the drywall has been installed, an opening should be cut to match the hole in the
pre-construction bracket. In most cases, the drywall installer will do this at the same time
that openings are cut for light switches, outlets and ceiling fixtures.
5. Skip directly to Part 2
Installation in Completed Structures
1. For this type is installation, a stud finder such as MCM #22-6840 is highly recommended.
This device will not only accurately located both edges of the stud, but will provide a
warning of nearby electrical wiring.
2. When deciding on a final location to install ceiling speakers, extreme care should be
taken to ensure that obstructions do not exist, such as air ducts, plumbing and electrical
wiring.
3. Locate the studs in the ceiling between which the speaker will be mounted. Using a
pencil, mark a spot directly in the center of the two studs
4. Locate the round cardboard mounting template, included with the speaker, and using a
tape measure, determine its exact center point.
5. Poke a small hole in the template, and place the template on the ceiling, lining up the
hole with the spot marked on the ceiling. Lightly trace the outer circumference of the
template with a pencil.
6. Using a wallboard saw, similar to MCM #22-7597, cut around this circumference. This
type of saw is especially useful, as its rigid design and sharp point allow it to “plunge” into
the wall with no need to drill a pilot hole.
7. Slowly remove the round section of drywall from the ceiling, taking care not to allow too
much insulation to fall (in attic installations).
Alternative to Steps 5~7
The MCM Hole Cutter, #22-7385, will complete steps 5, 6 and 7 in one quick step. For
complete information to this product, check out our website at www.mcminone.com.
Part 2
1. Remove the front grille from the speaker to be installed. This is most easily
accomplished by rotating the plastic mounting clips outward, and pressing then towards
the front speaker frame. This will cause the screw heads, behind the grill, to push the
grill out from inside. In some cases, it may be necessary to gently pry the grill from the
front. This may be done with a small knife blade or micro size flat blade screwdriver. In
this case, extreme care should be taken not to damage the plastic frame around the grill.
2. Rotate the four mounting clips so they are flat against the side of the rear speaker
enclosure. If necessary, loosen the four mounting screws, from the front of the speaker,
to allow these clips to rotate freely within their bracket.
3. Attach the speaker wire to the ( – ) and ( + ) connections on the rear of the enclosure.
Take care to observe correct polarity.
4. Fully insert the speaker into the ceiling hole and begin to tighten the four mounting
screws. Care should be taken when tightening these screws. Make sure the screwdriver
is secure in the head of the screw and does not slip out and damage the speaker cone.

5. As screws are tightened, the plastic mounting clips will rotate clockwise and draw in
against the inside of the wallboard. If using a drill to tighten screws, tighten all four until
the speaker frame just makes contact with the ceiling. From there, it is best to use a
hand screwdriver to fully tighten. This will prevent breakage of the plastic mounting clips.
6. In a cross pattern, (i.e. left, right, then up, down) tighten all four screws, by hand, until the
speaker frame is snug against the ceiling. Take care not to over-tighten as this may
damage the mounting clips or the mounting frame.
7. Once all screws are tightened, the grill may be reinstalled on the front of the speaker.
8. The other end of the speaker wire is now ready for connection to the sound source
Warranty
MCM Custom Audio products are warranted against manufacturer defects for a period of 12
months from the original date of purchase. This warranty is limited to manufacturer defects, in
either materials or workmanship. MCM an InOne company, or any other worldwide divisions of
Premier Farnell PLC, are not responsible for any consequential or inconsequential damage to any
other component, structure or the cost of installation or removal of said items.
This warranty will not cover damage due to improper use such as (an not limited to) damaged
cones, mounting frames, voice coils or items damaged by whether damaged items.
For questions or specific information regarding warranty replacement or repair, contact:
MCM, an InOne company
www.mcminone.com
800-543-4330