User Manual

result in improved atness. Positioning the
subwoofer close to a corner boosts the
subwoofer output but may cause asymmet-
rical spatial imaging at low frequencies.
Operating Environment
The 7040A subwoofer is designed for
indoor use only. The ambient temperature
should be 15-35 °C (50-95 °F) and the rel-
ative humidity 20-80 %. Condensation is
not allowed. If it has been stored or trans-
ported in a cool environment, the product
must be allowed to warm up in its packing
to the ambient temperature before con-
necting mains power.
Sufficient amplifier cooling and reflex
port functioning is required when the
subwoofer is installed in a restricted space,
such as a cabinet or integrated into a wall
structure. See section “Flush Mounting the
Subwoofer.” A restricted space must be
suciently ventilated to prevent ambient
temperature rise above 35 °C (95 °F).
Do not cover the driver of the subwoofer.
Do not place the subwoofer so that there is
less than 10 cm (4 in) of free space in front
of the grille.
Thick carpets under the subwoofer can
block the ventilation clearance needed for
cooling the amplier unit. To ensure proper
functioning of the reflex port the reflex
port side (opposite of the connector panel)
should have a minimum clearance of 7.5 cm
(3 in).
Flush Mounting the
Subwoofer
If the subwoofer is flush mounted into a
wall or a cabinet, ensure amplier cooling
and unrestricted airow from the reex port.
Make the recess 7.5 cm (3 in) wider than the
subwoofer. Place the subwoofer into the
right end of the recess with the driver side
facing the room. This leaves sucient 7.5
cm (3 in) of free space for the reex port.
The height and depth of the recess should
not be much larger than the subwoofer.
Setting the Input Sensitivity
The 7040A has the same sensitivity as 8010,
8020 and M030 monitors in free eld. How-
ever, when placed near reecting surfaces
the sensitivity of 7040A typically must be
attenuated due to increased wall loading.
A typical initial setting for the rotary sensi-
tivity control is -4 dBu. The +12 dBu setting
provides maximum attenuation The use of
proper measuring equipment with careful
listening is highly recommended.
Phase Alignment by
Listening
Connect an audio frequency signal gener-
ator to LEFT IN or RIGHT IN input of the
7040A and feed in an 85 Hz tone. Connect
a monitor to the corresponding output, so
that the test signal is reproduced by both
subwoofer and monitor.
Toggle the -180°
phase switch (DIP 4
from left) "ON" and
"OFF". Set it to the
position giving the
lowest sound level at the listening position.
Next, toggle the -90°
phase switch (DIP 3)
"ON" and "OFF", and
again set it to the posi-
tion which gives the
lowest sound level.
Finally, invert the -180°
phase switch (DIP 4)
position to the oppo-
site setting. Now you
can remove the test
signal.
Figure 4. The effect of phase difference between the subwoofer and the main loudspeakers
Phase Difference: 0°
85 Hz
Phase Difference: 180°
85 Hz
Phase Difference: 270°
85 Hz
Phase Difference: 90°
85 Hz
Figure 5. Flush mounting the subwoofer.
Note the clearance needed on the reflex
port side.
Table 1. Suggested Bass Roll-Off settings
Subwoofer placement Bass Roll-Off
setting
Near to a wall -2 dB
In a corner -6 dB
Flush mounted -2 dB
ON
OFF
ON
OFF
ON
OFF