1. General Description
1. General Description
1. General Description
1. General Description
1. General Description
The Genelec 1091A active subwoofer
is a powerful low frequency loudspeaker,
incorporating all the amplifier and
crossover electronics needed to com-
bine it with the Genelec 1029A moni-
tors.
Drivers
Drivers
Drivers
Drivers
Drivers
The 1091A contains a single 210mm
(8") low frequency driver, housed in a 15
litre vented cabinet.
Crossovers
Crossovers
Crossovers
Crossovers
Crossovers
The active crossover within the ampli-
fier unit filters the input signal, the sen-
sitivity can be attenuated by 8dB in 2dB
steps. Due to the input sensitivity of the
1091A subwoofer it can only be used
with the Genelec 1029A active monitor.
Amplifiers
Amplifiers
Amplifiers
Amplifiers
Amplifiers
The amplifier unit is mounted between
the radiation ports for optimum cooling.
The 1091A amplifier output power is
70W. The amplifier incorporates spe-
cial circuitry for driver overload protec-
tion.
2. Installation
2. Installation
2. Installation
2. Installation
2. Installation
The subwoofer is supplied with a mains
cable and operating manual. Once un-
packed check that the subwoofer volt-
age selector switch is set to the correct
setting and then place the subwoofer in
a suitable position. The amplifier panel
and ports can be positioned facing a
wall or pointing upwards, they should
never be facing the floor. Before con-
necting the audio signals, ensure that
both the subwoofer and the main moni-
tors are switched off. Audio connec-
tions to the subwoofer are made via
balanced XLR and balanced
1
/
4
" jack
connectors.
Signals from the source
are fed to the 1029A input connector,
and signals for the subwoofer are taken
from the 1029A sub output connectors
(see Figure 1 below). When used in
Figure 2: The effect of phase on the system.
Figure 1: How to cable the system.
conjunction with the 1029A the bass
"roll-off" (switch 2) on the 1029A should
be in the ON position. Once all connec-
tions have been made, the subwoofer
and main monitors are ready to be
powered up.
Avoiding an uneven frequency re-
Avoiding an uneven frequency re-
Avoiding an uneven frequency re-
Avoiding an uneven frequency re-
Avoiding an uneven frequency re-
sponse.
sponse.
sponse.
sponse.
sponse.
Considering a usual room, a free stand-
ing speaker is always surrounded by
walls that will generate reflections. These
walls act as acoustical mirrors to the
speaker's radiation, enhancing (see top
of figure 2) or cancelling (bottom part of
figure 2), the direct sound at the listen-
ing position. The cancellation occurs at
a certain frequency which is primarily
determined by the distance from the
sub to the front wall, however the dis-
tance to other walls also affects the
cancellation frequency.
Moving the cancellation frequency
Moving the cancellation frequency
Moving the cancellation frequency
Moving the cancellation frequency
Moving the cancellation frequency
There are basically two ways to over-
come this problem. The first is to posi-
tion the speakers far enough from the
wall to move the interference dip below
the operating range of the speaker. To
move the dip down to 30 Hz, the dis-
tance needed is 2.8 meters. This would
not be possible in most rooms simply
because of lack of space.
The second method is to push the
speaker as close to the wall as possible
to decrease the time delay of this reflec-
tion relative to the direct sound. This
moves the interference problem to a
higher frequency. If the distance is
small enough then the frequency where
the dip occurs is above the operating
range of the subwoofer. If the distance
is decreased so the subwoofer is flush
against the wall then the mirror image of
our speaker created by the wall now
merges completely with the actual
speaker radiation. Because of this "dou-
ble" speaker effect the total sound power
radiated into the room has gained up to
6 dB.
S e t t i n g t h e I n p u t S e n s i t i v i t y
S e t t i n g t h e I n p u t S e n s i t i v i t y
S e t t i n g t h e I n p u t S e n s i t i v i t y
S e t t i n g t h e I n p u t S e n s i t i v i t y
S e t t i n g t h e I n p u t S e n s i t i v i t y
The subwoofer is set to the same sensi-
tivity as the 1029A in free field condi-
tions. However when placed near to
reflecting surfaces the sensitivity typi-
cally needs to be attenuated due to
increased room loading. A typical start-
ing point would be -4 dB. This is
achieved by adjusting the DIP switches
on the amplifier plate. The use of proper
measuring equipment together with
careful listening is highly recommended.
The maximum attenuation by the use of
one switch is 8 dB. However an attenu-
ation of 12 dB is possible by activating
all switches. The switches do not add
linearly.
3. Maintenance
3. Maintenance
3. Maintenance
3. Maintenance
3. Maintenance
No user serviceable parts are to be
found within the amplifier unit. Any main-
tenance of the unit should only be un-
dertaken by qualified service person-
nel.
4. Safety Considerations
4. Safety Considerations
4. Safety Considerations
4. Safety Considerations
4. Safety Considerations
Although the 1091A has been designed
in accordance with international safety
standards, to ensure safe operation and
to keep the instrument under safe oper-
ating conditions, the following warn-
ings and cautions should be observed.
Servicing and adjustment should only
be performed by qualified service per-
sonnel. Opening the amplifier's rear
panel is strictly prohibited except by
persons who are aware of the hazards
involved.
It is forbidden to use this product with
an unearthed mains cable, which may
lead to personal injury.
There must be at least a 100mm gap
between the amplifier plate and any
other surface or obstruction. This is to
allow sufficient air to circulate and cool
the amplifier.
WARNING!
WARNING!
WARNING!
WARNING!
WARNING!
This equipment is capable of delivering
sound pressure levels in excess of 85dB,
which may cause permanent hearing
damage.
5. Guarantee
5. Guarantee
5. Guarantee
5. Guarantee
5. Guarantee
This product is guaranteed for a period
of ONE year against faults in materials
or workmanship. Refer to supplier for
full sales and guarantee terms.
1029A
1091A
(rear view)
SOURCE
LEFT RIGHT
XLR / Male
¼" STEREO JACK
1029A
Enhancement of direct sound
85 Hz
Cancellation of direct sound
85 Hz
