Bowers & Wilkins CWM Cinema 6 Installation Manual page 6

Preparing For Installation
Choosing cable
Excessive resistance in the speaker cable wastes
power and alters the frequency response of the
speaker. Always try to keep the resistance as low as
possible with the loop resistance preferably below 0.5
ohms for non-critical applications and below 0.2 ohms
for best results. Use the table of figure 7 to calculate
the minimum gauge of cable required.
Fitting The Wall Frame/Baffle (existing wall
construction/retrofit)
Figure 4 illustrates this procedure.
Position the template at the desired location of the
speaker. The template is marked with both vertical and
horizontal centre lines to aid alignment.
Trace round the outer edge of the template and cut
neatly just inside the line.
To improve the mechanical integrity of the wall and
reduce the likelihood of rattles, we recommend you
apply a bead of mastic/caulking along the joints
between the back of the plasterboard (sheetrock) and
the studs in the vicinity of the speaker.
Run the cable to the aperture, allowing enough length
to comfortably connect the speaker, but not too much,
as the excess may rattle against the structure.
Fitting the Wall Frame/Baffle (new drywall
construction)
Figure 5 illustrates this procedure.
The speaker can be installed once the wall is
completed in the same manner as retrofitting, but it is
easier to position and cut the hole if the optional pre-
mount kit (PMK) is used before the plasterboard is
fitted.
Staple or nail the PMK to the studs as described in the
instructions with the kit. Run the cable and secure it to
the fixing point on the PMK. Allow enough length to
comfortably connect the speaker, but not too much, as
the excess may rattle against the structure.
Results are affected by how well the plasterboard
(sheetrock) is attached to the studs and we
recommend you apply a bead of mastic/caulking as
well as screwing or nailing the panels to the studs in
the vicinity of the speaker.
Once the board is fitted, the inner flange of the PMK
serves as a guide for a hole router or saw.
If extra acoustic isolation to adjoining rooms is required
or some protection against the spread of fire, use the
optional back box in place of the PMK. Follow the
instructions with the back box for fitting and running
the cable.
When fitting the plasterboard (sheetrock), use
mastic/caulking between the sheets and the back box
to avoid rattles. Rout or saw out the speaker aperture
using the back-box flange as a guide. Depending on
the diameter of the router, you may need to square off
the corners with a saw.
Fitting the Wall Frame/Baffle (solid wall
construction)
In order for the bass performance not to be
compromised, the speaker requires a cavity volume of
at least 20 litres (0.8 cu ft). This means that, in a
standard 10cm (4 in) thick wall, the cavity will extend
beyond the boundaries of the speaker frame. It is
possible to provide this cavity simply by using a lintel,
covering the hole with plasterboard (sheetrock) and
fitting the speaker as described above for retrofitting
into a drywall. (Figure 6) However, the back box
provides a useful means of defining a minimum volume.
Follow the instructions with the back box for fitting and
running the cable. If using a wet plaster finishing
method, first apply a thin layer of PVA adhesive
(polyvinyl-based caulking) onto the back box before
plastering to avoid rattles as a result of the plaster
shrinking away from the back box as it dries.
If using plasterboard (sheetrock), stick the sheets to
the surfaces of the back box using flexible
mastic/caulking. Rout out the aperture using the flange
as a guide. Depending on the diameter of the router,
you may need to square off the corners with a saw.
In all cases, we recommend not using cement or
mortar to fix the back box into the brick or block-work.
Rattles are best avoided by using flexible
mastic/caulking and wedges.
Damping the Wall Cavity
Fill the wall cavity or back box, but not the space
immediately behind the speaker, with unlined fibreglass
or mineral wool matting. The packing density should be
just enough to comfortably prevent the material from
dropping or sagging over time. In an open wall cavity,
fill to a distance of at least 30cm (1 ft) above and
below the speaker.
IMPORTANT: Ensure that the materials you use meet
local fire and safety regulations.
Connecting and Fitting the Speaker
(all installation types)
All connections should be made with the equipment
switched off.
Connect the cable, observing the correct polarity.
With the grille removed, position the speaker in the
aperture and screw in the 6 screws visible from the
front. These screws automatically swing out clamping
dogs that locate behind the mounting surface. Ensure
that they have located properly before fully tightening
the screws. A certain amount of flexing of the frame is
allowed to take up unevenness in the mounting
surface, but do not over-tighten the screws as
excessive distortion of the speaker frame may result.
Customising
The frame has a paintable white semi-matte finish,
ready if necessary to be re-finished to match room
decor. Fit the paint mask before re-finishing. Do not
re-finish the drive units or baffle area behind the grille.
Avoid touching the drive units, as damage may result.
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