MartinLogan Grotto I User manual

Grotto i
user’s manual
tm

Serial Number ___________________________________
Record your serial numbers here for easy reference. You will need this information
when filling out your warranty registration. Grotto i’s serial number is located near
the bottom of the backplate and also on the shipping container.
Grotto i Settings:
Level ___________________________________________
25Hz Level ______________________________________
Phase __________________________________________
Low Pass Filter ___________________________________
A/V Processor Bass Management Settings:
Main Speaker Size ________________________________
(large recommended for full range speakers)
Center Speaker Size ______________________________
(small recommended)
Surround Speaker Size ____________________________
(small recommended)
Level ___________________________________________
High-Pass _______________________________________
Low-Pass _______________________________________
WARNING! Do not use your Grotto i loudspeakers outside of the country of original sale—voltage requirements
vary by country. Improper voltage can cause damage that will be potentially expensive to repair. The Grotto i is
shipped to authorized MartinLogan distributors with the correct power supply for use in the country of intended
sale. A list of authorized distributors can be accessed at www.martinlogan.com or by emailing [e-mail].
The lightning bolt flash with arrowhead symbol, within
an equilateral triangle, is intended to alert the user to
the presence of uninsulated “dangerous voltage” within
the product’s enclosure that may be of sufficient mag-
nitude to constitute a risk of electric shock.
The exclamation point within an equilateral triangle is
intended to alert the user to the presence of important
operating and maintenance (servicing) instructions in
the literature accompanying the appliance.

Thank you—to you the MartinLogan owner,
for loving what we do,
and
for making it possible for us to do what we love.

4 Contents & Introduction
Contents & Introduction                          4
Installation in Brief 5
Controls and Connections                        6
Control.......................................6
Connections...................................7
2-Channel Mode ...............................8
Multi-Channel Mode............................9
2-Channel/Multi-Channel Mode . . . . . . . . . . . . . . . . . . 10
2-Channel Mode Using Speaker Level Inputs . . . . . . . . . 11
2-Channel Mode With 2-Channel Output . . . . . . . . . . . 12
Why the Filters Are Not Equal
Sub Out—Using Multiple Subwoofers . . . . . . . . . . . . . 13
AC Power Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacing the Fuse
Break-In
Placement15
Listening Position
Installing In A Cabinet
Ask Your Dealer
Enjoy Yourself
Room Acoustics 16
Your Room
Terminology
Solid Footing
Home Theater17
MartinLogan Exclusives                          18
Servo-Controlled Dynamic Drivers
Proprietary Switching Amplifier
25Hz Level Control
Frequently Asked Questions & Troubleshooting     19
Dimensioned Drawings                         20
General Information                            21
Specifications
Warranty and Registration
Serial Number
Service
Glossary of Audio Terms                         22
Contents & IntroduCtIon
Congratulations! You have invested in one of the
world's premier subwoofers
The MartinLogan Grotto i represents the culmination
of an intensive, dedicated research program directed
toward creating a world class reference subwoofer using
advanced technologies and without compromising dura-
bility, reliability, craftsmanship or aesthetics.
The Grotto i subwoofer uses a custom 10-inch high-
excursion driver to deliver deep, tight, well-defined bass.
Servo-control woofer technology minimizes distortion. A
proprietary digital amplifier drives the output stage with
precision and extremely high efficiency. Low-pass filtering
and phase control have been designed to make integrat-
ing the Grotto i subwoofer with both MartinLogan and
non-MartinLogan products both seamless and simple.
The materials in your new Grotto i subwoofer are of the high-
est quality and will provide years of enduring enjoyment and
deepening respect. The cabinetry is constructed from the
highest quality composite material for acoustical integrity.
This User's Manual will explain in detail the operation of
your Grotto i subwoofer and the philosophy applied to its
design. A clear understanding will help you obtain maxi-
mum performance and pleasure from this most exacting
subwoofer system.
In accordance with the European Union WEEE (Waste
Electrical and Electronic Equipment) directive effective
August 13, 2005, we would like to notify you that this
product may contain regulated materials which upon
disposal, according to the WEEE directive, require spe-
cial reuse and recycling processing.
For this reason MartinLogan has arranged with our distrib-
utors in European Union member nations to collect and
recycle this product at no cost to you. To find your local
distributor please contact the dealer from whom you pur-
chased this product, email [e-mail] or visit
the distributor locator at www.martinlogan.com.
Please note, only this product itself falls under the WEEE
directive. When disposing of packaging and other related
shipping materials we encourage you to recycle these
items through the normal channels.

Installation in Brief 5
We know you are eager to hear your new MartinLogan
subwoofer, so this section is provided to allow fast and
easy set up. Once you have your subwoofer operation-
al, please take the time to read, in Grotto, the rest of the
information in this manual. It will give you perspective on
how to attain the greatest possible performance from this
most exacting woofer system.
If you should experience any difficulties in the setup or
operation of your MartinLogan subwoofer, please refer
to the Room Acoustics and Placement sections of the
this manual. Should you encounter a persistent problem
that cannot be resolved please contact your authorized
MartinLogan dealer. They will provide you with the appro-
priate technical analysis to alleviate the situation.
WARNING!
• Hazardous voltages exist inside—do not
remove cover.
• Refer servicing to a qualified technician.
• To prevent fire or shock hazard, do not
expose this module to moisture.
• Turn amplifier off and unplug subwoofer
should any abnormal conditions occur.
• The power cord should not be installed,
removed, or left detached from the speaker
while the other end is connected to an AC
power source.
• The main power switch near the AC inlet shall
remain readily operable.
• No candles or other sources of open flame
should be placed on the speaker.
• No liquids either in glasses or vases should be
placed on speaker.
• Speaker should not be exposed to dripping or
splashing liquids.
• The terminals marked with the lightning bolt
symbol should be connected by an instructed
person or by way of ready made terminals
• The power cord should remain readily oper-
able should any abnormal conditions occur.
Step 1: Unpacking
Remove your new subwoofer from its packing. Note:
Retain original packing materials for future use.
Step 2: Placement
Ideally, place the subwoofer in a corner near the front of the
room. Please see the Placement section (page 16) for more
details.
Step 3: Signal Connection
Use the best cables you can. High quality cables, available
from your specialty dealer, are recommended and will
give you superior performance.
Attach your preamplifier/processor outputs through cables
to the signal input area located on the subwoofer’s rear
panel. Please see the Controls and Connections section
(pages 6–15) for more details.
If you plan to connect your subwoofer using Speaker Level
(high level) inputs, please refer to the 2-Channel Mode
Using Speaker Level Inputs section (page 12 for more
details.
Step 4: Power Connection (AC) (see warning)
Set your subwoofers power switch to ‘Standby’. Make
sure the level knob is set at 0. Plug the subwoofer into a
wall outlet. Review the AC Power Connection section (page
15) of this manual for more details.
Step 5: Setting the Controls
• Set the Level knob to 3 or 4.
• Set the Power switch to ‘Auto’.
• Set the 25Hz Level knob to 0.
• Set the Phase to 90°.
• Set the Low Pass Filter to the closest setting below the
low-end frequency response of your main speakers.
These settings are only a beginning point. Your subwoofer
will need proper setup to optimize performance. Please
see the Controls and Connections section (pages 6–15) for
more details.
Step 6: Listen and Enjoy
InstallatIon In BrIef

6 Controls and Connections
Controls and ConneCtIons
Figure 1 Connection and control panel
Controls
Figure 2 Graph demonstrating the fre-
quencies effected by the 25Hz Level
controls
Level
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 system’s low end seem more
extended and accurate.
Low Pass Filter
When the Grotto i 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 fil-
ter is active.
As a general rule the Low Pass
Filter should be set at the option
approximately equal to (or below)
70% of your main speaker’s low-
est frequency response. Example:
The MartinLogan Vista’s low-
est frequency response is 43Hz.
70% of 43Hz equals 30.1, so you
should set the Grotto i’s low pass
filter to 30Hz. Remember, this is a
general rule. We advise that once
you try the recommended set-
ting using the formula above, you
should try the surrounding settings
to see which sounds best.
Optionally, an internal module
in the Grotto i can be upgraded
with a custom tailored Low Pass
Filter setting for use with the
MartinLogan CLX loudspeaker.
When this upgrade is imple-
mented the 30 Hz setting on the
Grotto i becomes the CLX Low
Pass Filter setting.
Phase Control
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 dif-
ferent 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
The 25Hz Level knob signifi-
cantly adjusts frequencies where
peaks and dips of different ampli-
tudes often manifest in real world
environments. The ideal setting
is dependent on room size and
construction, system configura-
tion and personal preference.

Controls and Connections 7
Right Out / Left Out
Should only be used if con-
necting this sub between
a pre-amp and amplifier.
Connect to the Left In/Right
In on the amplifier. The High
Pass: Out control filters the
output from these connections.
Sub Out
For systems utilizing multiple
subwoofers. Connect Sub Out
to the LFE Input or Right In /
Left In on additional sub(s).
LFE In
Connect to LFE Out on your
A/V processor. The subwoofers
Low Pass Filter control does
not effect this connection.
Crossover settings for LFE In
are controlled through the A/V
processor.
Right In/Left In
Connect to Main-Out or Pre-
Out on your receiver/pre-amp.
Grotto i’s Low Pass Filter con-
trol effects the signal received
through these inputs.
Speaker Level In
This set of binding posts pro-
vides a place to connect the
subwoofer using standard
speaker cable. Grotto i’s Low
Pass Filter control effects the
signal received through these
inputs.
Status Light
The Grotto i is equipped with a
multi-color LED to indicate the
current status of the woofers.
The following list explains the
meaning of the different colors:
No color: No power. The
subwoofer is not plugged in,
or the fuse has blown.
Green: Play mode. This indi-
cates the subwoofer detects
an audio signal and has auto-
matically switched into play
mode.
Yellow: Standby mode. This
indicates the Power switch is
set to Standby, or the sub has
detected no audio signal for
more than forty minutes and
has automatically switched
into standby mode.
Red: Initializing or Safe
mode. This indicates that the
subwoofer is initializing. This
also indicates if the subwoofer
temperature has exceeded
nominal operating range. If
the subwoofer overheats,
please allow it to cool and
reset it by unplugging the unit
and plugging it back in.
AC Power Connection & Fuse
Figure 3 Rear connection panel.
Connections

WARNING! Turn the Master Power switch Off
and unplug it before making or breaking any
signal connections!
This setup is recommended if your subwoofer will be used
in a 2-channel only system. When a signal is connected to
the subwoofers Left In/Right In, the Low Pass Filter control
is active.
Signal Connection (see figure 4):
1 Connect the left out/right out from your preamp/receiver
to the Left In/Right In of the subwoofer. Use quality RCA
interconnects. If your preamp/receiver only has one set of
outputs you need to obtain Y adapters from your dealer.
Recommended Control Settings:
1 Calculate the number equal to 70% of your main loud-
speaker’s lowest frequency rating. Set the Low Pass Filter
switch to the closest setting below the resulting number.
2 Play familiar music with bass content. Increase the Level
control until the music has deep extended bass. Be
careful to avoid levels that become overwhelming.
3 Try the phase control in different settings until the best
blending is obtained. If you are using the subwoofer to
augment other MartinLogan products, we suggest start-
ing with the phase set at 90°.
4 If you have completed steps 1–3 and still have weak or
boomy bass, adjust the 25Hz Level knobs to compen-
sate for these anomalies. Experiment with the controls
and listen to the effects. Try to find a position that
sounds correct to you. Experiment by changing the Level
control while adjusting these knobs. Find a position that
gives you deep extended bass and good blending with
your main speakers.
Figure 4 Signal connection for 2-channel mode.
8 Controls and Connections
2-Channel Mode

Controls and Connections 9
Multi-Channel Mode
This setup is recommended if you will use your subwoofer
in a dedicated home theater or multi-channel system. When
a signal is connected to the subwoofer’s LFE In, the Low
Pass Filter control is NOT active. Your processor handles
most of the bass management.
Signal Connection (see figure 5):
1 Connect the LFE out of the processor to the LFE In.
WARNING!
Based on the performance of most processors,
it is recommended that MartinLogan center
and effects type speakers (i.e. Stage, Cinema,
Theater, and Script i) not be run in large, wide or
full range mode. Doing so may potentially dam-
age the speaker if the processor attempts to drive
the speaker beyond its rated frequency range.
This warning also applies to products from other
manufacturers.
It is recommended to run center and effects type
speakers in limited or narrow mode.
Recommended Control Settings:
1 With multi-channel source material playing, adjust the
Level control to your preferred level.
2 Try the phase control in different settings until the best
blending is obtained. If you are using the subwoofer to
augment other MartinLogan products, we suggest start-
ing with the phase set at 90°.
3 If you have completed steps 1–2 and still have weak
or boomy bass, adjust the 25Hz Level knob to com-
pensate for these anomalies. Increase and decrease to
controls and listen to the effects. Try to find a position
that sounds correct to you. Experiment by changing the
Level control while adjusting these knobs. Find a position
that gives you deep extended bass and good blending
with your main speakers.
4 Follow the bass management setup instructions in your
processor manual to fine-tune the subwoofer level.
Figure 5 Signal connection for multi-channel mode.

This setup is recommended if your subwoofer will
be used in both 2-channel mode and as a LFE chan-
nel in a multi-channel system. By following this setup,
you will allow your processor to handle most of the
bass management while running in multi-channel
mode, and relinquish control of the low pass filter to
the subwoofer when running in a 2-channel mode.
Signal Connection (see figure 6):
1 Connect the left and right out of your preamplifier to
the subwoofer’s Left In / Right In. Use 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 output of the processor to the sub-
woofer’s LFE In. Use quality RCA interconnects.
Recommended Control Settings:
1 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 10).
2 Calculate the number equal to 70% of your main loud-
speaker’s lowest frequency rating. Set the Low Pass Filter
switch to the closest setting below the resulting number.
3 While playing familiar music with bass content, turn
the level control up until the music has deep bass that
is not overwhelming.
4 Try the phase control in different settings until the
best blending is obtained. If you are augmenting
MartinLogan loudspeakers, we suggest you start with
Phase set at 90°.
5 Use the bass management section of your processor’s
speaker setup to set the subwoofer level at an appro-
priate level. Follow the instructions in your processor’s
manual to fine-tune the subwoofer level.
6 If your processor offers the option to setup crossovers for a
subwoofer, we recommend that you start with the fol-
lowing settings—Crossover: 70Hz, High-Pass: 12dB,
and Low-Pass: 24dB. The optimal setting for these
options may vary depending on your room and listen-
ing preferences.
2-Channel/Multi-Channel Mode
Figure 6 Signal connection for 2-channel/multi-channel mode.
10 Controls and Connections