Level Knob
Setting the level too high will cause the bass to seem bloated
and is the single most common cause of bad sounding
subwoofers. A rule of thumb is that the subwoofer should
not draw attention to itself, but should simply make the
systems low end seem more extended and accurate.
Low Pass Filter Knob
When the Grotto is connected in multi-channel mode (via
its LFE input), the low pass filter is not active and your
processor handles the bass management. When connected
in 2-channel mode (via its speaker or line level left/right
input), the low-pass filter is active.
As a general rule the low pass filter should be set at the
option approximately equal to 70% of your speaker’s lowest
frequency response.
Example:
The MartinLogan Aeon i’s
lowest frequency response is 43Hz. 70% of 43Hz equals
30.1, so you should set the Grotto’s low pass filter to 30Hz.
Remember, this is a general rule. We advise that once you
try the recommended setting using the formula above, you
should try the surrounding settings to see which sounds best.
Phase Control Switch
The phase control is entirely dependent on the size and
configuration of your listening environment, the placement
of the unit, and your seating arrangement. Due to the way
bass sound waves develop in different rooms, there is no rule
of thumb for setting phase. For instance, if your room has
a peak at the subwoofer crossover area, you may wish to
set the phase so the actual acoustic outputs of the subwoofer
and main speakers are out of phase. Experiment, try dif-
ferent settings and be patient.
25Hz Level Knob
The 25Hz Level knob significantly adjusts the level between
20 and 30Hz by ±12dB. This is an area where peaks and
dips of different amplitudes often manifest in real environments.
This setting is dependent on room size and construction,
system configuration and personal preference.
Auto/On/Standby Power Switch
The Auto/On/Standby switch controls Grotto’s energy sav-
ing feature. When set to 'Auto', the Grotto will turn on
when a music signal is detected and off when there is none.
The 'On' setting prevents the Grotto from entering energy
saving mode. The 'Standby' setting forces the Grotto into
energy saving mode. While set to 'Standby’, the Grotto will
not perform.
Status Light
The Grotto is equipped with a multi-color LED to indicate
the subwoofers current status. The following list explains the
meaning of the different colors:
No color:
No power. The Grotto is not plugged in.
Yellow:
Energy saving mode and safety mode. If the power
switch is set to ‘Auto’ this indicates the Grotto detects no
audio signal and has automatically switched into energy
saving mode. Setting the power switch to ‘Standby’ will
force the Grotto into this mode. This also indicates if the
Grotto’s temperature has exceeded nominal operating
range. The Grotto will resume normal play mode when the
temperature-sensor reports a safe operating temperature.
Green:
Play mode. If the power switch is set to ‘Auto’ this
indicates the Grotto detects an audio signal and has auto-
matically switched into play mode. Setting the power
switch to ‘On’ will force the Grotto into this mode.
A
BOUT THE
C
ONTROLS
About the Controls 5
Figure 1.
Grotto controls located on the back of the subwoofer.
Summary of Contents for GROTTO
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