Positioning In The Room; Setting The Phase Control - Genelec F Two Operating Manual

CONNECTOR
FOR OPTIONAL
WIRED SYSTEM
VOLUME CONTROL
Figure 2. Connectors and controls of the F Two.
LINK IN connector. The LFE channel on the
F Two can reproduce signals up to 120 Hz.
Next connect the main loudspeakers to the
corresponding L, R, C, LS and RS signal out-
puts on the subwoofer with RCA cables.
Once all connections have been made, the
subwoofer and main loudspeakers are ready
to be powered up.

Positioning in the room

The placement of the subwoofer in the room
affects the overall frequency response and
sound level of the system dramatically, as at
low frequencies the effects of the room are
strong. Even a slight change in the location of
the subwoofer can cause a marked difference
in the frequency balance and often patient
and methodical experimentation and testing
is needed to find the optimum placement.
The placement will also affect the bass
roll-off rate and the phase difference between
the main loudspeakers and the subwoofer.
These effects can be compensated using the
controls in the subwoofer but we recommend
that at first you leave the switches untouched
and concentrate on finding the position where
the subwoofer gives the smoothest response,
and only then use the controls to fine-tune
the balance and phase alignment between
the subwoofer and the main loudspeakers.
Start by placing the subwoofer close to the
center of the front wall. We recommend a dis-
tance of less than 60 cm / 24" to the wall. This
INPUT CONNECTORS
IN
SYSTEM
LEFT RIGHT
VOLUME
CONTROL
OUT
LEFT RIGHT
OUTPUT CONNECTORS
position gives increased acoustic loading and
sound pressure level due to the proximity of
the front wall and floor. Ideally the subwoofer
and main loudspeakers should be positioned
symmetrically and at an equal distance from
the listening position.
If the frequency balance is not quite right,
try moving the subwoofer to the left or right
along the wall so that different room modes
are excited at different levels. Positioning
the subwoofer close to a corner will boost
the bass level at lower frequencies and may
cause asymmetrical spatial imaging.
Setting the playback level
The "LEVEL +10 dB" switch on the subwoof-
er's connector panel should be switched to
"ON" when the F Two is used with Genelec G
Three or G Four active loudspeakers and the
"LEVEL +10 dB" switches on the main loud-
speakers are set to "1."
Setting the Bass
Roll-Off switches
The acoustic response of the subwoofer
may have to be matched to the characteris-
tics of the room and the positioning in which
it will be used (see Table 1). To adjust the
subwoofer to match these characteristics
use the ''BASS ROLL-OFF' control switches
located on the connector panel. When all
Roll-Off switches are 'OFF', a flat anechoic
response is obtained.
MAINS INPUT
L LS C
LFE/LINK IN
R RS
SUBWOOFER
LINK IN
LEVEL
LEVEL + 10 dB
MAX
L LS C ON
-180°
-4 dB -90°
-2 dB -270°
BASS PHASE
ROLL-OFF
R RS LINK OUT
CONTROL SWITCHES
-LINK IN
-LEVEL+10 dB
-BASS ROLL-OFF
-PHASE
The effect of incorrect phase alignment
between the main loudspeakers and the
subwoofer is a drop in the frequency
response of the whole system at the main
loudspeaker / subwoofer crossover fre-
quency. The phase difference between the
main loudspeakers and subwoofer at the
listening position is dependent upon the dis-
tance from the listener to the subwoofer in
relation to the main loudspeakers. To avoid
phase differences between the left and right
main loudspeakers and the subwoofer, the
subwoofer should be placed close to the
center of the front loudspeaker array.
crossover allow compensation for incorrect
phase alignment. Four settings are provided
between 0° and -270°.
Connect an audio frequency signal generator
to a signal input on the subwoofer which has
a main loudspeaker connected to the corre-
sponding "OUT" connector. Set the generator
to 85 Hz. If a signal generator is not available,
it is possible to use an audio test recording
which has a test frequency in the range 70
Hz to 100 Hz. Suitable test signals can be
downloaded at www.genelec.com.
POWER SWITCH
ON
MAINS INPUT
50 / 60 Hz
120 W 230 V~
POWER
MIN
SUBWOOFER LEVEL
ADJUSTMENT

Setting the phase control

Two phase matching switches in the
Coarse phase
correction method