MartinLogan Grotto [9/24] Channel mode using speaker level inputs

Connections and Control Settings 9

This setup is recommended if your Grotto will be used in a

2-channel only system with full-range front loudspeakers.

When a signal is connected to the Grotto’s Left/Right Inputs,

the Grotto’s internal low pass filter is active.

Signal Connection (see figure 8):

1 Connect the left and right outputs of your amplifier to the

left and right speaker level (high level) inputs of the Grotto

using quality speaker cable.

If your amplifier only has one set of outputs you may

connect your amplifier to your speakers as normal and

run an additional set of cables from your speakers to the

Grotto’s left and right speaker level (high level) inputs.

It is also possible to connect the left and right outputs

of your amplifier to the left and right speaker level (high

level) inputs of the Grotto and run an additional set of

cables from your Grotto to the speakers.

Recommended Control Settings (see figure 9):

1 Set the 25Hz Level control to 0.

Set the low-pass filter switch to the closest option equal

70% of your loudspeakers lowest frequency response.

3 While playing music with bass content, turn the level con-

trol up until the music has deep extended bass, being

careful to avoid levels that become overwhelming.

4 Try the phase control in different settings until the best blend-

ing is obtained. If you are using the Grotto to augment other

MartinLogan products, we suggest you start with the phase

set at 90° (0° if you are using Script™ loudspeakers).

5 If you have completed steps 1–4 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.

Figure 9. Control settings for 2-channel mode using speaker level inputs.

2-Channel Mode Using Speaker Level Inputs

Figure 8. Signal connection for 2-channel mode using speaker level inputs.