The GENELEC HT324AC active loudspeaker
is designed for neutral sound reproduction
at high SPLs in large Home Theater rooms.
Its cabinet has been designed for optimum
placement in the limited space above or
below a video screen, but it can also be
installed in vertical configuration. Acousti-
cally the HT324AC is identical to Genelec
HT324A. The system consists of a 160 litre
loudspeaker cabinet and a 19” 7U rack mount
amplifier unit.
The cabinet contains two 305 mm (12”)
bass drivers, a 130 mm (5”) midrange, and
a 25 mm (1”) treble driver. The midrange
and treble drivers are mounted in a Genelec
Directivity Control Waveguide™ (DCW™)
which can be rotated through ±90° for either
horizontal or vertical mounting. The cabinet
low frequency -3 dB point is at 32 Hz and the
bass response extends down to 27 Hz. The
high frequency response extends up to 22 kHz
(-3 dB).
Each amplifier unit contains a three-chan-
nel active crossover, driver overload protec-
tion circuits, and four separate power ampli-
fiers producing 2 x 400 W, 350 W and 120 W
of short term power in the bass, midrange,
and treble channels respectively. The crosso-
ver filter incorporates tone controls to enable
the user to accurately match the speaker to
the local acoustic environment.
Unpacking
The Genelec HT324AC is shipped in a single
box, containing a cabinet, an amplifier unit, a
mains connecting cable, a LED connecting
cable, a loudspeaker connecting cable and
one Allen key. (See Fig 1)
Before installing the system, check all
items for damage and omissions. If there are
any damaged products, contact directly the
distributor and insurance agent. If there are
any missing components, contact your local
dealer or Genelec.
Installing the amplifier
The Genelec HT324AC amplifier electron-
ics is encased in an standard 19” 7U rack
chassis. The unit should be well ventilated to
prevent overheating, there must be a supply
of air to the front and sufficient ventilation to
dissipate the generated heat from the space
behind the amplifier unit. The maximum per-
missible ambient temperature is 35° C (95°
F) If the system overheats it will stop operat-
ing until a safe temperature is reached.
Each amplifier unit has been calibrated
at the factory with the loudspeaker cabinet
it is packed with. They also share the same
ID number. Make sure that each amplifier is
connected to the cabinet bearing the same
ID number when installing multiple loud-
speakers.
Make sure that the amplifier is positioned
so that the loudspeaker connecting cables
will reach. Longer cable lengths can be
ordered from the manufacturer upon special
request. A space 120 mm deep should be left
behind the rear panel of the amplifier unit to
allow for the cable connectors.
Check that the amplifier unit is wired to the
correct mains voltage for your power supply.
The correct mains voltage for the amplifier
unit is shown at the bottom of the sticker on
the rear panel of the amplifier unit.
The amplifier mode can be switched
between ON and standby modes by a
remote control unit connected to the respec-
tive 12 V DC trigger inputs on the amplifier
back panel. Activate the function by turning
the "REMOTE CONTROL" dip switch on the
amplifier panel to "ON".
Loudspeaker positioning
The HT324AC is designed to be flush
mounted in either the vertical or horizontal
configuration. The DCW™ should be rotated
so that the treble and midrange drivers align
vertically. This ensures that optimum symme-
try is obtained.
Note that the DCW™ plate is heavy, care
must therefore be taken when removing and
replacing the DCW™. To rotate the DCW™
plate, proceed as follows:
• Place the loudspeaker in its intended
listening orientation.
• Unscrew the eight M5 fixing screws on
the edges of the plate using the 4 mm
Allen key provided with the system.
• Carefully pull the plate a small distance
away from the cabinet.
• Rotate the DCW™ so that the midrange
and treble drivers are aligned vertically
(treble driver on top) and remount the
DCW™ plate reversing the procedure
above.
Flush mounting of the
loudspeaker
Although the HT324AC may be used suc-
cessfully as a free standing loudspeaker,
flush mounting is strongly recommended for
acoustical reasons. Flush mounting improves
the bass response and efficiency and also
enhances the midrange transient and fre-
quency response.
The loudspeaker has its acoustical axis
midway between the midrange and treble
drivers. This axis should be used as the lis-
tening and measuring axis of the system.
(See Fig 1)
The listening position should be between
2 ... 3.5 m (6½ ... 11½’) from the loudspeak-
ers. The loudspeaker should be aimed so
that the acoustical axis of the two loudspeak-
ers meet at ear height at the center of the
listening area. The loudspeakers should not
be mounted too high as this increases the
required vertical tilt of the loudspeaker and
reduces the optimum listening area.
The ceiling, side walls and especially the
rear wall should be acoustically absorbent at
low frequencies. The loudspeaker mounting
wall should be acoustically hard and there-
fore reflective. The mounting wall should be
angled so that the loudspeakers are correctly
aimed. Great care should be taken over how
the loudspeaker is mounted into the wall.
Note the following:
• A space 50…100mm (2..4”) wide can be
left around the loudspeaker.
• Cover the space around the
loudspeaker with a facing panel, this
should be fixed to the wall. Leave a gap
of about 5..10 mm (¼..½”) between the
loudspeaker and the panel. Fill this gap
with a soft rubber gasket to allow for
possible cabinet movement.
• Ensure that the loudspeaker cables can
reach the rear of the loudspeakers.
• If a light (e.g. wooden) wall is used,
the loudspeaker cabinet should be
mounted on vibration isolators, with a
resonant frequency of around 2…8 Hz,
to prevent vibrations from being
transmitted to the wall and impairing
the low frequency performance. The
space around the cabinet should be
filled with absorbent mineral wool or
foam plastic. The walls must be well
braced.
• For a solid wall (e.g. concrete), the
loudspeaker may be directly mounted to
the wall without vibration isolators. The
space around the cabinet should be
filled with mineral wool or sand bags.
System
