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HEAVY WOODEN WALL
ABSORBING
MATERIAL
AMPLIFIER
REMOVED
FROM ENCLOSURE
VIBRATION
ISOLATORS
f ~ 2-8 Hz
Figure 3: Flush mounting the loudspeaker in
a wall constructed of wood
cally aimed so that the acoustical axis of the
loudspeakers meet around ear height at the
reference listening position. In the horizontal
plane the loudspeaker should be positioned
according to the standard stereophonic (60
degrees between left-right channels) or mul-
tichannel (ITU-R BS.775-1) placement rec-
ommendation.
The ceiling, side walls and especially the
rear wall should be acoustically absorbent at
low frequencies. The wall in which the loud-
speakers are mounted should have a high
acoustical mass to properly implement a low
frequency radiation condition into half space
and be angled so that the loudspeakers are
correctly aimed. However, the loudspeak-
ers should not be mounted too high as this
increases the required vertical tilt of the loud-
speaker (maximum tilt angle < 20 degrees)
and reduces the optimum listening area. Great
care should be taken over how the loudspeaker
is mounted into the wall. Note the following:
A space 50 to 100 mm (2 to 4") wide can
be left around the loudspeaker. Cover the
space around the loudspeaker with a facing
panel that should be fixed to the wall. Leave
a gap of about 5 to 10 mm (¼ to ½") between
the loudspeaker and the panel. Fill this gap
with a soft rubber gasket to allow for possible
cabinet movement (see Figure 6).
Ensure that the loudspeaker cables can
reach the rear of the loudspeaker cabinets.
Regardless of the type of front wall con-
struction the loudspeaker cabinet should be
mounted on vibration isolators, with a resonant
frequency between 2 to 8 Hz, to prevent vibra-
tions from being transmitted to the wall and
impairing the low frequency performance.
If a heavy wooden front wall construction
CONCRETE WALL
SAND
BAGS
AMPLIFIER
REMOVED
FROM ENCLOSURE
VIBRATION
ISOLATORS
f ~ 2-8 Hz
Figure 4: Flush mounting the loudspeaker in
a wall constructed of concrete
is used, the space around the cabinet should
be filled with absorbent mineral wool or foam
plastic. The wooden wall structure must be
heavily braced to achieve sufficiently high
mass and rigidity (see Figure 3).
In a solid wall (e.g. concrete) structure, the
space around the cabinet should be filled
with either absorbent mineral wool or sand
bags (see Figure 4).
The wall can also be constructed of a com-
bination of materials to achieve high acousti-
cal structural mass that will disable low fre-
quency sound propagation and provide high
LF sound isolation (see Figure 5). Acoustic
consultants will be able to provide details and
design these structures.
Ensure that the cabinet is flush with the
surface of the wall. Discontinuities in the loud-
speaker mounting wall will cause diffraction,
which leads to inferior frequency response
and imaging. So, if a decorative cloth frame
is used to cover the wall, make sure that the
edges adjacent to the loudspeaker are less
than 20 mm (
3
/
") deep. The cloth must be very
4
thin Tricot or an acoustically transparent mate-
rial otherwise the high frequency response of
the system will be adversely affected. Genelec
approved cloth grilles are available.
Mode indicator LED
The loudspeaker is provided with a three-
colour indicator LED on the DCW™ panel.
When the LED is green, it indicates that the
loudspeaker is ready for use. Standby mode
is indicated by yellow colour. Amplifier clip-
ping is indicated by a blinking red light and
thermal protection mode by a constant red
light. If clipping is indicated reduce the signal
level so that the LED stops blinking. If the
MULTI-LAYERED WALL
(WOOD, CONCRETE,
BRICKS)
AMPLIFIER
REMOVED
FROM
ENCLOSURE
CONCRETE
STRUCTURE
VIBRATION
ISOLATORS
f ~ 2-8 Hz
Figure 5: Flush mounting the loudspeaker
in a wall constructed of a combination of
materials.
SPEAKER
RUBBER GASKET
(5-10 mm / ¼-½")
FACING PANEL
FIXED TO THE WALL
(50-100 mm / 2-4")
WALL
Figure 6: Covering the gap between the
wall and the loudspeaker cabinet.
red LED stays on constantly, switch off the
loudspeaker and the audio source and let the
amplifier cool down. Check that the ventila-
tion around the amplifier is not blocked. There
should be a clearance of more than 100 mm
(4") between the amplifier face panel and any
solid surface at the back. If the red light does
not come off, contact authorised Genelec
service.
The LED can be deactivated if you find it
disturbing in a darkened room by turning both
the "POWER LED" and "STANDBY LED"
switches on the amplifier panel to "OFF".
Maintenance
No user serviceable parts are to be found
within the amplifier unit. Any maintenance or
repair should only be undertaken by quali-
fied service personnel. Ensure that if fuse
replacement is required, only fuses of the
same voltage and current rating are used.
Remember to disconnect the power supply
by removal of the mains cable, before fuse
replacement.
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