Specifications

8 Connections and Control Settings
Using an A/V processor and the Grotto’s low pass filters.
This setup is recommended if your Grotto will be used in both
2-channel mode and as a LFE (0.1) channel in a multi-
channel mode. By following this setup, you will allow your
processor to handle most of the bass management while run-
ning in multi-channel mode, and relinquish control of the low
pass filter to the Grotto when running in a 2-channel mode.
Signal Connection (see figure 6):
1 Connect the left and right outputs of your preamplifier to
the left and right inputs of the Grotto using quality RCA
interconnects. If your preamplifier only has one set of
outputs you need to obtain Y adapters from your dealer.
2 Connect the LFE/0.1 output of the processor to the LFE
input of the subwoofer using quality RCA interconnects.
Recommended Control Settings (see figure 7):
1 Set the 25Hz Level control to 0.
2 Set your front speakers for wide, large or full mode in
your processor. Set the center and effects type speakers
in limited or narrow mode (see the warning on page 7).
3
Set the low-pass filter switch to the closest option equal to
70% of your loudspeakers lowest frequency response.
4 While playing music with bass content, turn the level
control up until the music has deep extended bass that
is not overwhelming.
5 Try the phase control in different settings until the best
blending is obtained. If you are augmenting MartinLogan
loudspeakers, we suggest you start with the phase set
at 90° (0° if you are using Script™ loudspeakers).
6 If you have completed steps 1–5 and still have weak or
boomy bass, adjust the 25Hz knob to compensate for
these anomalies. Turn the 25Hz control up and down and
listen to the effects that it has on the music. Try to find a
position that sounds correct to you. Experiment by chang-
ing the level control while adjusting this knob. You should
be able to find a position that gives you deep extended
bass and good blending with your main speakers.
7 Use the bass management section of your processor’s
speaker level setup option to set the subwoofer level at
an appropriate level. Follow the instructions in your
processor’s manual to fine-tune the subwoofer level.
8 If your processor offers the option to setup crossovers for a
subwoofer, we recommend that you start with the follow-
ing settings—Crossover: 70Hz, High-Pass: 12dB, and
Low-Pass: 24dB. The optimal setting for these options may
vary depending on your room and listening preferences.
2-Channel/Multi-Channel Mode
Figure 6. Signal connection for 2-channel/multi-channel mode.
Figure 7. Control Settings for 2-channel/multi-channel mode.