JL Audio f212 User Manual

Owner’s Manual

f212

IMPORTANT SAFETY INSTRUCTIONS

WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,

DO NOT EXPOSE THIS PRODUCT TO RAIN OR MOISTURE.

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE
AMP PANEL OR SPEAKER. NO USER SERVICEABLE PARTS INSIDE. REFER
SERVICING TO QUALIFIED PERSONNEL.

1) Read the Instructions — All safety and operating instructions should be
read before the subwoofer is operated.

2) Retain the Instructions —  e safety and operating instructions should be
retained for future reference.

3) Heed Warnings — All warnings on the subwoofer and in the operating
instructions should be followed.

 e lightning  ash 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
su cient magnitude to constitute a risk of
electric shock to persons.

 e exclamation point within an
equilateral triangle is intended to alert the
user to the presence of important operating
and maintenance instructions in the
literature accompanying the product.

4) Follow Instructions — All operating and use instructions should
be followed.

5) Water and Moisture —  e subwoofer should NOT be used near water – for
example, near a bathtub, washbowl, sink, laundry tub, in a wet basement,
near a swimming pool, etc.

6) Ventilation —  e subwoofer should be situated so that its location or
position does not interfere with its proper ventilation. For example, the
subwoofer should not be situated on a bed, sofa, rug, or similar surface
that may block air ow over the heatsink  ns. If placing the subwoofer in
a “built-in” installation, ensure that air ow to the heat sink at the rear of
the subwoofer is not impeded. Do not cover the subwoofer heatsink with
tablecloths, curtains, etc.

9) Heat and Flames —  e subwoofer should be situated away from heat
sources such as radiators, heat registers, stoves,  replaces, or other devices
which produce heat. Do not place candles on top of or near the subwoofer.

10) Power sources —  e subwoofer should only be connected to a power supply of
the type described in the operating instructions or as marked on the subwoofer.

11) Power Cord Protection — Power-supply cords should be routed so that they
are not likely to be walked on or pinched by items placed upon or against
them, paying particular attention to cords at plugs, convenience receptacles,
and the point where they exit the subwoofer.

Page 2 | Fathom f212

12) Cleaning —  e subwoofer should be cleaned only as recommended in the
operating instructions.

13) Nonuse Periods —  e power cord of the subwoofer should be unplugged
from the outlet when the subwoofer is le unused for long periods of time.

14) Lightning and Power Surges — We recommend that you disconnect the
subwoofer from the electrical outlet during electrical storms and/or recurring
power interruptions to prevent damage due to power surges.

15) Object or Liquid Entry — Care should be taken so that objects do not fall
into and liquids are not spilled onto the subwoofer enclosure. Do not expose
the subwoofer to dripping or splashing from liquids. Do not place objects
 lled with liquids on top of, or near the subwoofer. For example:  ower
vases, beverages, liquid-fueled lamps, etc.

16) Damage Requiring Service —  e subwoofer should be serviced by quali ed
service personnel when:

a. the power-supply cord or plug has been damaged
b. objects have fallen or liquid has been spilled into the subwoofer
c. the subwoofer has been exposed to rain
d. the subwoofer does not appear to operate normally or exhibits a marked

change in performance
e. the subwoofer has been dropped or the cabinet has been damaged
f. the subwoofer driver’s cone and/or suspension has been

physically damaged

WARNING

17) Servicing —  e user should not attempt to service the subwoofer beyond
what is described in the operating instructions. All other servicing should be
referred to quali ed service personnel.

18) Overloading — Do not overload wall outlets, extension cords, or outlet strips
as this can result in a risk of  re or electric shock.

19) Grounding —  is subwoofer is supplied with a three-prong, grounded
power cord. Precautions should be taken so that the grounding means of the
subwoofer are not defeated. Defeating the grounding prong on the subwoofer
power cord could increase the risk of electric shock and could result in
permanent damage to the subwoofer’s electronics.

THIS SUBWOOFER IS CAPABLE OF PRODUCING VERY HIGH SOUND
PRESSURE LEVELS. PLEASE EXERCISE RESTRAINT IN ITS OPERATION TO
PROTECT YOUR HEARING FROM PERMANENT DAMAGE.

Page 3 | Fathom f212

FCC COMPLIANCE STATEMENT

NOTE:  is equipment has been tested and found to comply with the limits of Part 15 of the FCC
Rules.  ese limits are designed to provide reasonable protection against harmful interference in
a residential installation.  is equipment generates, uses and can radiate radio frequency energy
and, if not installed in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television reception,
which can be determined by turning the equipment o and on, the user is encouraged to try to
correct the interference by one or more of the following measures:

- Reorient or relocate the receiving antenna.

- Increase the separation between the equipment and receiver.

- Connect the equipment into an outlet on a circuit di erent from that to which the
receiver is connected.

- Consult the dealer or an experienced radio/TV technician for help.

TABLE OF CONTENTS

Important Safety Instructions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Introduction:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Product Overview: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Placing your Fathom in Your Listening Room: . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

Unpacking your Fathom: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Front Control Panel Layout: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Rear Control and Connector Panel Layout: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Front Panel Controls in Detail: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-17

Connecting your Fathom(s): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-25

Recommended Setup Procedure: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26-30

Frequently Asked Questions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Cleaning Your Fathom: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Troubleshooting: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Limited Warranty / Service Information: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Speci cations: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

INTRODUCTION

Congratulations on your purchase of a JL Audio Fathom powered subwoofer
system.  is product has been critically engineered to deliver exceptional
performance in your home theater or audio system for many years to come.

As a company, we are intensely committed to core research into
high-performance loudspeaker and ampli er technologies. JL Audio’s long­excursion subwoofer driver designs are widely considered as reference standards for
linear behavior and high output. We have also focused our e orts to create powerful
ampli er and signal-processing technologies speci cally aimed at delivering
exceptional low-frequency performance. Your Fathom combines these core
disciplines within a compact, beautifully cra ed package to deliver an unparalleled
listening experience.

JL AUDIO TECHNOLOGIES INCLUDED
IN FATHOM SUBWOOFERS

DMA-Optimized Motor System

DMA is JL Audio’s proprietary Dynamic
Motor Analysis system aimed at
improving dynamic motor behavior. As a
result of DMA optimization, loudspeaker
motors remain linear in force over an
extreme range of excursion and also
maintain a highly stable  xed magnetic
 eld over a wide power range.  is leads
to vastly reduced distortion and faithfully
reproduced transients... or put simply:
tight, clean, articulate bass.

OverRoll™ Surround
(U.S. Patent #5,687,247 and #5,949,898)

 e OverRoll™ surround spans over
the driver’s mounting  ange, utilizing
available diameter wasted in conventional
speakers.  is allows the use of the wider
roll necessary to control high-excursions
without sacri cing precious cone area.

W-Cone™ (U.S. Patent #6,496,590)

 e W-Cone™ is a unit-body cone
assembly that delivers astonishing cone
sti ness with minimal mass.

Floating-Cone™ Attach Method
(U.S. Patent #6,501,844)

 is assembly technique ensures proper
surround geometry in the assembled
speaker for better excursion control and
dynamic voice coil alignment.

Plateau-Reinforced Spider Attachment
(U.S. Patent #6,118,884)

 is high-integrity suspension attachment
relieves stress from the spider material at
high-excursions for enhanced reliability.

Elevated Frame Cooling Technology
(U.S. Patent #6,219,431 and #6,229,902)

Delivers cool air, through slots directly
above the top-plate, to the voice coil of the
speaker.  is enhances power handling
and sound quality by minimizing
dynamic parameter shi s and power
compression.

Radially Cross-Drilled Pole Piece
(U.S. Patent #6,243,479)

 is innovative venting system greatly
enhances thermal dissipation and power
handling by directing air  ow onto the
voice coil former, working in conjunction
with the Elevated Frame technology.

High-Damping Feedback Circuit
(U.S. Patent #6,441,685)

 is proprietary, discrete control circuit
design allows our Class D switching
ampli ers to maintain an excellent
damping factor for improved transient
behavior and  delity.

Page 4 | Fathom f212

We sincerely thank you for your purchase and invite you to read this
manual thoroughly in order to achieve the highest level of performance with
your Fathom subwoofer system. Enjoy.

PRODUCT OVERVIEW

JL Audio Fathom subwoofers combine a state-of-the-art
JL Audio subwoofer driver and electronics/ampli er package within
a highly optimized enclosure to deliver an exceptional listening
experience in your home theater or home audio system.

 e subwoofer driver in your Fathom subwoofer system is capable of
outstanding linear excursion without distress or audible distortion.  is
reference-quality driver enables your Fathom to reproduce powerful low­frequency events with stunning impact and unprecedented accuracy. Derived
from JL Audio’s legendary W7 design platform, the Fathom f212 drivers o er
peak-to-peak excursion capabilities well in excess of 3 inches (76 mm), to
comfortably handle the dynamics of the most demanding program material.

To get the most from this long excursion driver platform, prodigious amounts
of controlled power are needed. Our electronics engineering team conducted
an intense analysis of typical program material and its dynamic demands in
order to balance current draw and actual output power requirements relative to
the system’s impedance characteristics. A er careful study, a pair of precisely
engineered switching ampli ers employing patented feedback technology were
created.  e advanced ampli er design in the F212 is capable of unclipped output
voltages equivalent to 3000 watts of RMS power when referenced to the nominal
loudspeaker impedance, allowing us to take full advantage of each driver’s full
excursion envelope.

 e beautiful cabinet enclosing the workings of your Fathom is also the result
of careful engineering. To contain the pressures created by the Fathom driver, we
utilized solid, CNC-cut, MDF material with extensive internal bracing features
and advanced assembly techniques.

Your listening room is the other enclosure that a ects the way your bass will
sound. All rooms create a speci c sonic signature, which must be e ectively
managed to achieve well-balanced low frequency performance. To aid in this
process, the Fathom includes an extensive set of signal processing tools aimed
at optimizing your Fathom’s performance within your listening space.  ese
features include JL Audio’s exclusive Automatic Room Optimization system.

As you can see from this brief introduction, there is a lot of technology in this
compact subwoofer.  e contents of this manual will explain the features, guide
you through the setup and tuning of your Fathom subwoofer and help you achieve
your ultimate low-frequency listening experience.

IMPORTANT

If you require assistance, we urge you to contact your authorized
JL Audio retailer for expert setup advice and service.

IMPORTANT! IT IS A VERY GOOD IDEA TO READ THE NEXT SECTION

BEFORE UNPACKING YOUR FATHOM. UNPACKING THE SUBWOOFER NEAR

ITS FINAL LOCATION IS RECOMMENDED.

Page 5 | Fathom f212

PLACING YOUR FATHOM IN YOUR LISTENING ROOM:

Your listening room or theater is an integral part of your sound reproduction
system.  e physical dimensions of the room and its furnishings, materials,
doors and windows play an important role in de ning how your system sounds.

When you place a sound source in an enclosed rectangular space, “standing
waves” are created, resulting from the relationship between the sound’s
wavelength and your room’s dimensions. In other words, standing waves result
from sound energy that is trapped in the room as it bounces back and forth
between opposing walls. Standing waves in the room create acoustic peaks and
dips where the sound is either louder or so er, based solely on your physical
position in the room. Energy also “builds up” at the room’s boundaries, creating
exaggerated bass response at certain frequencies.  ese fundamental room
resonances are called room “modes.”

 e moral of this mode story is to try and avoid seating positions in standing
wave peak or dip regions. It is highly recommended that you place your listening
chairs in areas where modal peaks and dips are moderate and do not reinforce
one another.  e two most obvious areas to avoid are those near the exact center
of the room and those close to any of the room’s walls.

Just as your listening seat can be in a peak or dip region, so can your
subwoofer. When placed in a room corner, a subwoofer maximally excites the
room’s mode structure, creating the strongest output with the fewest dips. When
the subwoofer is pulled away from a corner or wall, the room modes are excited
less, which can alter the sound at your listening seat.

Be sure to experiment with both your listening seat position and subwoofer
position to  nd the best solution. Careful experimentation usually leads to a
superior sounding system. Use our setup suggestions (illustrated on the opposing
page and the following pages) to get you started.

If you cannot avoid placing your sofa against the back wall or your
subwoofer in a less than optimal position, all is not lost. Your Fathom’s
Automatic Room Optimization (A.R.O.) System can dramatically improve
these less-than-ideal situations.

We recommend that you begin by placing your Fathom in the front of the
room, near the front le or right speaker. Placing it directly in the front corner

of the room will produce the maximum number of peaks and the minimum
number of dips in the bass response.  is can be advantageous because the
Fathom’s A.R.O. system can correct the primary peak very e ectively, whereas
dips in response cannot be corrected via equalization. Dips in response can only
be minimized via careful subwoofer and listener placement.

Placing the Fathom near solid walls will reinforce bass response and pulling
it away from solid walls will decrease bass. Increasing the distance between the
subwoofer and the walls may help to smooth upper bass response in some rooms.

We recommend that you avoid placing the Fathom near windows to prevent
rattling and sound transmission to the outside world.

If you are planning to install your Fathom
inside a cabinet, please refer to the
guidelines on page 8.

Page 6 | Fathom f212

Recommended Subwoofer Placement Options for One Fathom

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Page 7 | Fathom f212

SPECIAL CONSIDERATIONS FOR BUILT-IN INSTALLATIONS

Fathom subwoofers are designed to be “built-in” friendly. All typically
needed controls are located on the front panel above the woofer. A Fathom can
be easily integrated into custom cabinetry by following a few simple guidelines.

1) Allow 4 inches (10 cm) of clear space behind the Fathom’s amp panel for

adequate cooling and connector clearance.

2) On all other sides (except the bottom), allow at least 2 inches

(5 cm) clearance for adequate ventilation.

3) While the Fathom generally runs only warm during spirited operation, we do

recommend that adequate heat vents are included in any custom cabinet which
encloses the Fathom. Pairs of 3 inch (7.5 cm) diameter vents over the full cabinet
height (8 vents total, see diagram) will allow cool air to circulate over the amp
panel of your Fathom f212 subwoofer system keeping it cool and happy.

4) Your Fathom f212 subwoofer is capable of moving substantial quantities

of air. If the front of the f212 is covered by a custom grille, the grille
must have AT LEAST 170 square inches (1100 sq. cm.) of vent area.  is
grill area is equal to the woofer cone area for the f212 and will ensure
that the Fathom’s output is not choked by the custom cabinet.

Rear-view of cabinet install:

2 in. min .

VENT

VENT

VENT

VENT

VENT

VENT

VENT

VENT

2 in.
min.

Page 8 | Fathom f212

Using Two Fathoms

When using two Fathoms, try
placement near the front corners of the
room, at diagonally-opposite corners
of the room, or at the center points of
opposing walls as shown at right.

Experimentation with
subwoofer and listener
placement is recommended to
achieve the best results – the
bene ts can be substantial.

High-resolution measurements
and professional system calibration
are recommended for the best possible
results & system performance.

Recommended Subwoofer Placement Options for Two Fathoms

Page 9 | Fathom f212

Recommended Subwoofer Placement Options for Three Fathoms

Using Three or Four Fathoms

Research indicates that the
smoothest bass response for a large
listening area can be achieved using
four subwoofers, placing one at
the midpoint of each of the four
walls (although using two or three
subwoofers can be almost as good).

Experimentation with
subwoofer and listener
placement is recommended to
achieve the best results – the
bene ts can be substantial.

High-resolution measurements
and professional system calibration
are recommended for the best possible
results & system performance.

Recommended Subwoofer Placement Options for Four Fathoms

Page 10 | Fathom f212

Unpack this box close to where the
subwoofer will be placed.  e subwoofer
is PACKED upside down.  is box must be
 ipped over CAREFULLY to remove the
subwoofer and minimize e ort.

IMPORTANT

UNPACKING YOUR FATHOM

Now that you have determined your Fathom’s position in the room, you can
proceed with unpacking it near its intended location.

D

C

A

B

IMPORTANT: DUE TO THE WEIGHT OF THE FATHOM SUBWOOFER,
PLEASE EXERCISE CAUTION WHILE UNPACKING AND POSITIONING IT TO
PREVENT INJURY. IF POSSIBLE, ENLIST THE HELP OF A SECOND PERSON TO
FACILITATE THE PROCESS. TO MINIMIZE THE RISK OF INJURY, BEND YOUR
KNEES AND LIFT WITH YOUR LEGS, NOT YOUR BACK.

Detailed instructions on unpacking the subwoofer:

1. Place the carton on the  oor near its intended location in the room.

2. Open the top of the carton (observe markings on carton) and remove the manual,
calibration microphone and power cord.

3. Temporarily remove the split-foam packing inserts.

4. Untie and loosen the protective cloth cover to make later removal easier (do not
remove at this time). When you open the cloth cover, you are looking at the
bottom of the subwoofer cabinet.

5. Replace the split-foam inserts to protect the subwoofer’s cabinet
while unpacking.

6. Gently  ip the box on its side, folding back the carton  aps to the outside.

7. Holding the carton  aps back, gently  ip the carton onto its top (open end).

8. Pull the carton straight up until it clears the subwoofer and place to one side.

9. Remove the one-piece foam insert and place in the carton.

10. Remove the plastic bag and place in the carton.

11. Tilt the subwoofer forward (toward its grille) to remove the rear split-foam insert

 rst.  en tilt the subwoofer in the opposite direction (towards its ampli er
panel) to remove the remaining split-foam insert. Place both split-foam inserts
in the carton.

12. Remove the protective cloth cover and place in the carton.

IMPORTANT

IMPORTANT! PLEASE RETAIN ALL PACKAGING FOR SAFE TRANSPORTATION
OF THE SUBWOOFER AND FOR ANY FUTURE SERVICE NEEDS.

Page 11 | Fathom f212

Front Control Panel

 e labeled Figure below depicts the front control panel of a Fathom f212 subwoofer.

Power

page 14

A.R.O.

page 14-15

Level Mode

Input Mode

page 15

page 15

Master Level

page 16

Lights

page 16

LP Filter

page 16

LP freq. (H z)

page 16

e.l.f. trim (dB)

phase (deg.)

page 17

page 17

Polarity

page 17

Page 12 | Fathom f212

Rear Controls and Connectors

 e labeled Figure below depicts the rear panel of a Fathom f212 subwoofer.

Balanced Inputs

page 18

Unbalanced

Inputs

page 19

IEC-Style AC

Connector

page 21

Output to

Slave Connector

page 21

Input Mode

Switches

page 20

Page 13 | Fathom f212

FRONT PANEL CONTROLS IN DETAIL

Power Switch

 e “Power” switch determines the operational readiness of the Fathom
subwoofer and should be the only switch used to turn the Fathom on and o . Do not
use a power strip switch, switched outlet or any other external switch as these may
result in undesirable and potentially damaging transient pops. Do not unplug the
Fathom’s AC power cord while the unit is turned on.

 e power switch has three positions:

“On”:  e Fathom is fully powered at all times. Front panel lights are on unless

they have been turned o via the “Lights” switch.

“O ”:  e Fathom’s internal power ampli er is powered down. In this state,
a negligible current draw will exist for operating the main power relays. All front
panel lights are o .

“A ut o ”:  e Fathom will power up its internal ampli er when an audio signal is
present at any of its inputs and will power down the internal ampli er if no signal has
been detected at its inputs for thirty (30) minutes. When dormant, the Fathom will
draw a very small amount of current (< 5 watts) to power its signal-sensing circuitry.
Front panel lights will turn o when the Fathom powers down and light when the
Fathom powers up (unless they have been turned o via the “Lights” switch).

In the unlikely event that the Auto feature is not sensitive enough for a particular
system, use a Y-cable adaptor to split the incoming signal into both RCA or XLR
inputs on the Fathom.  is will increase the input sensitivity by 6 dB. Please be
aware that if the Auto sensitivity is too high or if there is signi cant noise on the
input cable, the Fathom may not turn o as desired. If this happens, remove the
Y-cable adaptor or look for the noise source in the upstream components.

IMPORTANT

Automatic Room Optimization (A.R.O.)

A powerful feature of the JL Audio Fathom subwoofers is their innovative
Automatic Room Optimization (A.R.O.) technology.  is one-touch system
serves to eliminate the single largest acoustic response peak in your home theater
at the main listening seat, greatly improving the in-room low-frequency response.
Calibration of the A.R.O. system is fully automated and takes only a few minutes to
accomplish. Please consult the next section of this manual for details on how to use
the A.R.O. system

Using the included JL Audio calibration microphone, the A.R.O. calibration
procedure takes less than three minutes. In brief, you will connect the included
microphone to the “Calibration Mic.” input, press the Calibrate button, and then
hold the microphone at ear height in your main listening seat during the test. A
series of tones will be played through the Fathom subwoofer, and the room response
will be automatically measured, analyzed and equalized to eliminate the single
largest acoustic room response peak at your listening seat. For detailed instructions

on the A.R.O. setup procedure, refer to pages 29-30.

Calibration Mic. Input

 is input is for connecting the supplied JL Audio calibration microphone to
the Fathom subwoofer. Connect one end of the supplied cable to the microphone
and the other end to this jack prior to using the A.R.O. system.  e A.R.O. system
is speci cally calibrated to this microphone and its connection scheme is speci c to
the supplied microphone.  e calibration sequence will not operate when a di erent
microphone is connected or if no microphone is connected.

Page 14 | Fathom f212

Demo Button

 e Demo button triggers a 20 second long tone sequence that brie y
demonstrates the signals used during A.R.O. calibration.  e Demo function is
useful for showcasing the output capability of the Fathom and to verify that the
Fathom (or multiple Fathoms) are operational during system troubleshooting.

To activate the demonstration sequence, press and hold the “Demo” button for
approximately 2 seconds (this built in delay helps prevent accidental activation).
Pressing and holding the “Demo” button will activate the demo sequence even if
the A.R.O. defeat function is active (see below.) Once the demonstration sequence is
complete, the Fathom will return to its previously set operating condition.

Defeat Button

 e “Defeat” button turns o or “defeats” the A.R.O. calibration system and
equalizer. Use this feature when you want to be sure that the A.R.O.’s equalization
is not in the signal chain. You can also use the “Defeat” button to audition both the
normal and the A.R.O. optimized settings in your home theater room.  is is a
great way to audibly verify what e ect the A.R.O. has in your room.

If “Demo” or “Calibrate” is pressed while the defeat function is active, “Defeat” is
automatically canceled. No other front panel controls will alter the A.R.O. Defeat state.

Calibrate Button

 e Calibrate button activates the ARO test sequence.  e calibration routine
will not start unless the supplied JL Audio test microphone is plugged into the
Fathom subwoofer. Once the calibration routine is complete, the green light in the
center of the “Calibrate” button will light and remain illuminated.  ese settings
are stored by the Fathom and will remain in memory even if power is disconnected.

During the ARO test sequence the Calibrate button’s green LED will alert the
user to two special conditions:

1. “Subwoofer level too low for A.R.O. calibration” via slow blinking,
approximately one blink per second

2. “Subwoofer level too high for A.R.O. calibration”, approximately three
blinks per second.

Input Mode Indicators

 e Input Mode indicator LEDs show the input mode, either “Master” or “Slave”,
selected by the switch on the Fathom’s back panel (unless the “Lights” switch is set to
“o ”). For further details, see page 20.

Level Mode

 e two-position Level Mode switch allows you to select between the following
modes:

“Reference”

In this mode, the Master Level control knob has no e ect on the Fathom’s output
level. Use this setting if you will primarily be controlling the subwoofer level via
your receiver or preampli er/processor. For those of us with small children or
overenthusiastic teenagers, this mode of operation will prevent direct manipulation
of the Master Level.

“Variable”

In this mode, the Master Level control knob determines the output level of
the Fathom subwoofer.  is mode is also useful when level matching the Fathom
subwoofer to a pair of stereo speakers in a two-channel system. Variable level
operation is needed for proper A.R.O. calibration.

Page 15 | Fathom f212

Master Level Knob

 e Master Level Knob is used to control the output level of the Fathom when

the Variable Level mode is selected on the front control panel.

When rotated fully counter clockwise, the Fathom’s output will be fully
muted. When at the “0” or straight up position, the Variable gain level matches
the Reference level setting. When turned fully clockwise, the Fathom’s output
level is 15 dB higher than the Reference setting.

Lights

 e “Lights” selector switch allows the user to select one of three indicator
light modes.

“O ” turns o all of the front panel LED’s at all times.

“Dim” sets all of the front panel LEDs to a low brightness level when the

Fathom is turned on.

“On” sets all of the front panel LEDs to full brightness level when the Fathom
is turned on.

IMPORTANT: WHEN TROUBLESHOOTING OR CALIBRATING THE A.R.O.

FEATURE, MAKE SURE THAT THE “LIGHTS” SWITCH IS SET TO “DIM” or “ON.”

LP Filter

 e Low Pass (LP) Filter selector switch determines the operating mode of the
Fathom’s built-in low pass  lter.

“O ” defeats the low pass  lter, completely removing this circuit from the
signal path.

“12 dB” sets the roll o slope of the low pass  lter to a 12 dB per octave slope
(Butterworth alignment).

“24 dB” sets the roll o slope of the low pass  lter to a 24 dB per octave slope
(Linkwitz-Riley alignment).

 e 24 dB setting more aggressively attenuates high frequencies above the LP
Frequency setting (see below). If you are using the Fathom’s built-in low pass
 lter, experiment with the LP Filter slope setting to achieve the best transition
to your satellite speakers. If you prefer to use the  lters and bass management
features in your receiver or preampli er, defeat the
on-board  lter by selecting the “O ” position.

LP Freq

 e Low Pass (LP) Frequency selector knob allows the user to choose the roll­o frequency of the Fathom’s internal low pass  lter.  e frequency is variable
between 30 Hz (full counter-clockwise) to 130 Hz (full clockwise).  is knob
does not a ect the input signal in any way if the LP Filter switch is set to “O ”.
80 Hz is a commonly used  lter frequency and usually serves as a good starting
point for adjustments.

IMPORTANT

Page 16 | Fathom f212

E.L.F. Trim

 e Extreme Low Frequency (“e.l.f. trim”) knob allows the user to apply
a certain amount of signal equalization at 25 Hertz (extremely low bass). At
full counterclockwise rotation, the signal at 25 Hz is cut by 12 dB. At “0” the
equalizer is set  at for zero contribution to the signal. At full clockwise rotation,
the signal at 25 Hz is boosted by 3 dB.

 e E.L.F. Trim feature is useful for tailoring the Fathom’s very low frequency
output for your particular room. Adding some boost can make certain material
more exciting. Using the cut function can help to compensate for room or
boundary gain in the low frequencies. Room boundaries and the room’s  nite
(limited) size naturally cause very low frequencies to be boosted relative to
other parts of the signal. As such, using the E.L.F. Trim feature to cut the lowest
frequencies can help to tame “bloat” or unnatural sounding low bass in small to
medium sized rooms (and can also reduce unwanted vibrations in the room or
throughout the house).

Polarity

 e Polarity switch allows the user to select between normal (0 deg) and
reversed (180 deg) signal polarity.  e Polarity switch will primarily a ect the
small frequency range around the crossover point between your subwoofer and
satellite speakers.

Unlike the Phase control, which e ectively adds time delay, the Polarity
switch produces an instantaneous reversal of the signal’s amplitude peaks.
For example, if at a given reference point a sine wave has an amplitude peak,
by  ipping the phase switch you instantly convert that peak into a trough
or amplitude dip. Because the e ect of the Polarity switch is immediate, it
compliments the operation of the Phase control and cannot be replaced by it.

When placing your Fathom in the room, experiment with the Polarity switch
before adjusting the “Phase” control. Either position of the Polarity switch may
provide a smoother transition between your Fathom subwoofer and the satellite
speakers. Use source material with good mid and upper bass content for evaluation.

Phase

 e Phase control knob allows the user to adjust the “timing” of the
subwoofer output relative to the main speakers.  e Phase control will primarily
a ect the small frequency range around the crossover point between your
subwoofer and satellite speakers.  e Phase control’s labels are referenced to 80
Hz since this is the most common crossover point between satellite speakers and
a subwoofer. Phase settings between 0 degrees (full counter-clockwise rotation)
and 280 degrees (full clockwise rotation) are possible.

Speaker, subwoofer, and listening seat positions vary greatly in home theater
installations. Since physical positioning of speakers relative to the room
boundaries and each other greatly a ects the perceived quality of sound output,
sometimes it is helpful to delay the subwoofer output.  is is exactly what occurs
when you turn the Phase control beyond 0 degrees.

Once your Fathom has been placed in your listening room to give you the
smoothest overall sound and a er you have determined the optimum “Polarity”
switch position (see preceding section), experiment with the position of the Phase
control. Using familiar source material with good mid and upper bass content,
adjust the Phase control and listen for better de ned mid-bass and a smoother
transition between the subwoofer and satellite speaker systems. If no single
setting sounds better than another, leave the Phase control at 0 degrees.

Page 17 | Fathom f212

CONNECTING YOUR FATHOM

Balanced Inputs

If your home-theater receiver or preampli er/processor provides balanced
outputs, the Fathom’s balanced inputs are the preferred connection. Balanced
connections are used extensively in professional studios and sound reinforcement
applications for a number of very good reasons. Besides ensuring proper grounding
between components, balanced signal transmission is designed to cancel induced
cable noise from the surrounding environment (particularly important with long
cable runs).  e bottom line is that your system will be far less likely to exhibit
humming or other extraneous noises if you use balanced connections.

 e Fathom subwoofers feature individual le and right balanced input
connections with XLR “combo” jacks.  ese special jacks accept either a
three-pin male XLR connector or a “tip-ring-sleeve” (TRS) 1/4-inch (6.3 mm)
connector for compatibility with a wide range of equipment.

For systems with a mono subwoofer or “LFE” channel connection, only the
jack labeled “Le or Mono” will be used.  is applies to most modern multi­channel receivers and preampli er/processors. Separate le and right input jacks
are provided for systems without a dedicated mono subwoofer connection.  is
typically applies to two-channel audio equipment.

Appropriate balanced cables are available from your JL Audio dealer and are
not included with the Fathom.

Technical Notes:

• Do not use the balanced inputs with unbalanced signals via adaptors.
 e unbalanced inputs of the Fathom are optically isolated and preferable in
situations where only an unbalanced signal source is available.

• Input connectors are con gured according to Audio Engineering Society
recommendations for balanced signal cables as follows:

XLR Connection

Pin 1: Shield
Pin 2: Positive
Pin 3: Negative

TRS connection:

Tip: Positive
Ring: Negative
Sleeve: Shield

 e Le and Right inputs on the Fathom
are internally summed to a single mono
channel. Since the Fathom is inherently a
“mono” or single channel device, you can
use the Le and Right inputs for the master
Fathom and then distribute the summed
mono signal to additional slave Fathoms in
the system.

IMPORTANT: I F Y O UR R E CE I V ER O R PR E A M PL I FI E R /P R O CE S S OR D O ES N O T
HAVE XLR OR 1/4-INCH TRS BALANCED OUTPUTS, PLEASE REFER TO THE
“UNBALANCED INPUTS” SECTION ON PAGE 19 FOR INPUT CONNECTION

IMPORTANT
INFORMATION. DO NOT ATTEMPT TO CONNECT UNBALANCED OUTPUTS
TO THE FATHOM’S BALANCED INPUTS VIA ADAPTORS.

Page 18 | Fathom f212

Unbalanced Inputs

 e Fathom subwoofer features individual le and right unbalanced RCA­type input connectors.  ese are the most commonly used connectors for home
audio applications and must be used if your receiver or preampli er/processor
does not provide balanced outputs. While unbalanced connections are not as
noise-immune as a balanced connection, Fathom subwoofers employ optical
isolation on the unbalanced inputs to minimize the possibility of noise in your
system.

For systems with a mono subwoofer or “LFE” channel connection, only
the RCA-type jack labeled “Le or Mono” will be used.  is applies to most
modern multi-channel receivers and preampli er / processors. Separate le and
right RCA-type input jacks are provided for systems without a dedicated mono
subwoofer connection.  is typically applies to two-channel audio equipment.

Technical Notes:

• When balanced outputs are not available on the signal source, you must use
the RCA-type unbalanced inputs. Fathoms feature optical isolation circuitry
on the unbalanced inputs to minimize the likelihood of ground loop
induced noise. Unbalanced input impedance is 10 kohms.

• Connections are industry-standard for unbalanced signal cables as follows:

RCA-type connection:

Tip: Positive
Sleeve: Negative

IMPORTANT

IMPORTANT: IF NOISE EXISTS AFTER CONNECTION, FATHOMS ALLOW
FOR GROUNDING OR ISOLATION OF THE UNBALANCED INPUTS. PLEASE
REFER TO THE “INPUT MODE SWITCHES” SECTION ON PAGE 20 OF THIS
MANUAL FOR FURTHER INFORMATION ON MINIMIZING NOISE.

Page 19 | Fathom f212

Input Mode Switches:

Two switches are located on the rear panel to control unbalanced signal

grounding and master/slave operation.

“Grounded / Isolated” Switch

 e “Grounded / Isolated” Input Mode switch a ects only the unbalanced
RCA inputs and is designed to facilitate a quiet, hum-free connection to your
audio or home theater system.  is feature is included to deal with the signal
grounding issues o en encountered in home theater systems when several
components from di erent manufacturers are interconnected.

 e Fathom ships with this switch in the “Isolated” mode. If, with all system
components connected and turned on (but no source material playing), you hear
a continuous low-frequency hum through your Fathom,  ip this switch to the
“Grounded” position and evaluate the di erence in the noise level. Use whichever
switch position provides the least hum or noise.

IMPORTANT: PLEASE NOTE THAT CHANGING ANY COMPONENT IN

THE OPTIMIZED SYSTEM (RECEIVER, AMPLIFIER, DVD PLAYER, CABLE OR

SATELLITE BOX, ETC.) COULD ALTER THE SIGNAL GROUNDING SCHEME

AND CAUSE HUM TO APPEAR IN YOUR PREVIOUSLY QUIET SYSTEM. IF YOU

ADD OR CHANGE AN UPSTREAM COMPONENT IN YOUR HOME THEATER

SYSTEM, YOU MAY NEED TO REVISIT THIS INPUT MODE SETTING ON THE

FATHOM SUBWOOFER FOR OPTIMUM NOISE PERFORMANCE. CABLE &

SATELLITE BOXES ARE PARTICULARLY TROUBLESOME IN THIS WAY.

IMPORTANT

Master / Slave Switch

 e Fathoms are designed to easily accommodate the implementation
of multiple subwoofers in your home theater system through a master/slave
connection chain.  is method allows you to utilize the signal processing
features of one Fathom to centrally control multiple Fathoms in the room.
Master/Slave functionality also makes it possible for the A.R.O. system to
optimize the response of a multiple subwoofer installation.

 e Fathom ships with this switch in the “Master” position. If you are using
a single Fathom you will use the “Master” position and you need not concern
yourself with this section any further.

If your installation incorporates two or more Fathoms, you will designate one
Fathom as the “Master” and all others in the system as “Slave” subwoofers via
the “Master/Slave” switch on the rear ampli er panel of each Fathom. LED’s on
the front panel of the Fathom are provided to indicate whether the “Master” or
“Slave” mode is selected for a given subwoofer.

From the Fathom operating in “Master” mode, the “Output to Slave” signal
carries any signal processing selected on the Master Fathom (including the
Master Level setting and A.R.O. processing) to further Fathoms operating in
“Slave” mode. “Slave” subwoofer signal processing and level controls will be
inoperable. In this mode, the user does not have to worry about level, crossover,
and other settings for the slave subwoofers.

Technical Notes:

• Selecting the “Slave” position defeats all user-de nable signal processing and
the master level control. Because of this, there are some special situations in
which you may want to operate a single Fathom in “Slave” mode. If you are
utilizing outboard signal processing and level-matching controls, activating
the “Slave” mode will prevent anyone from a ecting system parameters with
the manual controls on the Fathom.

Page 20 | Fathom f212

IMPORTANT

IMPORTANT: PLEASE REFER TO THE “SYSTEM CONNECTION DIAGRAMS”
ON PAGES 26-29 FOR MORE INFORMATION ON USING THE INPUT / OUTPUT
CONNECTIONS.

“Output to Slave” Connector

If you are operating more than one Fathom subwoofer in one home theater
system, you will designate one Fathom as the Master (see page 20), and then feed
signal from it to the remaining “Slave” Fathoms via this balanced XLR output.
 e “Output to Slave” cable can be connected to the “Le or Mono” balanced
XLR input on the next Fathom. When a Fathom is in “Slave” Mode, its “Output
to Slave” connection can be used to pass signal to further Fathoms operating in
“Slave” mode.

 e “Output to Slave” connector is designed to be used as follows:

1) From the “Master” Fathom’s “Output to Slave” connector to the  rst “Slave”
Fathom’s “Le or Mono” XLR balanced input.

2) From the  rst “Slave” Fathom’s “Output to Slave” connector to the second
“Slave” Fathom’s “Le or Mono” XLR balanced input.

3) From the second “Slave” Fathom’s “Output to Slave” connector to the third
“Slave” Fathom’s “Le or Mono” XLR balanced input. Etc, etc. (up to ten
Fathoms may be connected in this con guration).Appropriate balanced
cables with XLR terminations are available from your JL Audio dealer and
are not included with the Fathom.

Technical Notes:

•  e “Output to Slave” signal carries any signal processing selected on the

Master Fathom (including the Master Level setting and A.R.O. processing)
to further Fathoms operating in “Slave” mode.

• From Fathoms operating in “Slave” mode, the “Output to Slave” signal is an

exact, bu ered replica of the balanced input signal, making this method of
signal distribution preferable to using
Y-adapters or splitters.

• Use only shielded, connection cables with high quality

XLR connectors for Master/Slave connection. Never use unbalanced cables
with adaptors.

IEC-Style AC Connector

 e IEC-style AC cord receptacle receives the heavy-gauge, 6  . (1.8 m) long,
power cord included with your Fathom subwoofer. Your Fathom should only be
powered from a 120 V AC, 60 Hz outlet. Do not use any AC power cord other
than the one supplied with the Fathom.

 e Fathom subwoofer is a very powerful device and can draw a lot of current.
If too many components are connected with a Fathom subwoofer to one electrical
outlet, you risk tripping a household circuit breaker during very demanding
program material. If this happens, split the Fathom and other components
between two AC electrical circuits. If possible, for maximum performance,
dedicate an AC circuit to each Fathom.

Page 21 | Fathom f212

PROCESSOR (BALANCED OUTPUTS) RECEIVER / PROCESSOR (UNBALANCED OUTPUTS)

PRE OUT

REAR CENTER

FRONT

FRONT

L

REAR

SUB

R

OUTPUTS

OR

FATHOM REAR CONTROLS (MASTER)

SYSTEM CONNECTION DIAGRAM 1:
One Fathom to
Home Theater Receiver or
Home Theater Preamp/Processor

Most home theater receivers and
preamp/processors provide a single
(mono) subwoofer output. When
connecting a mono subwoofer output
to your Fathom, you will only use the
Fathom’s “Le or Mono” input.

Two connection types are available
for connecting the Fathom to your home
theater system: balanced (XLR or 1/4­inch TRS connector) and unbalanced
(RCA-type connector). Balanced
connections provide superior noise
rejection and ensure proper grounding
between components. If your receiver or
processor has balanced outputs, we highly
recommend that you use them.

In the connection diagram at le ,
balanced connections are shown as solid
lines, unbalanced connections are shown
dotted. You will only use one of these
input connection methods (not both).

WARNING! TURN OFF THE FATHOM AND ALL OTHER EQUIPMENT IN THE
SYSTEM BEFORE MAKING OR CHANGING ANY CONNECTIONS!

WARNING

Page 22 | Fathom f212

SYSTEM CONNECTION DIAGRAM 2:
Multiple Fathoms to
Home Theater Receiver or
Home Theater Preamp/Processor

To greatly simplify using multiple
subwoofers in a single home theater
system, Fathoms incorporate a
“Master/Slave” signal distribution system.
 is allows control of all the Fathoms in a
system from a single “Master” unit.

First, you will select one of the Fathom
subwoofers as the “Master” via its upper
“Input Mode” switch. Generally, you
will designate the Fathom closest to the
receiver/preamp as the master. In some
cases; for example, when the control panel
of certain units is di cult to access, you
may prefer to designate the one which is
easiest to access as the master.

Two connection types are available
for connecting the master Fathom to your
home theater system: balanced (XLR or
1/4-inch TRS connector) and unbalanced
(RCA-type connector). Balanced
connections provide superior noise
rejection and ensure proper grounding
between components. If your receiver or
processor has balanced outputs, we highly
recommend that you use them to connect
to the Fathom designated as the master.

In the connection diagram at le ,
balanced connections are shown as solid
lines, unbalanced connections are shown
dotted. You will only use one of these
input connection methods for the Fathom
designated as the master (not both).

 e remaining Fathoms in the system
will be con gured as “Slave” units via
their upper “Input Mode” switches.
Using balanced XLR cables, you will
connect the master Fathom’s “Output to
Slave” to the “Le or Mono” balanced
input of the  rst slave Fathom.  at
slave unit’s “Output to Slave” connector
will feed the “Le or Mono” input of
the next slave unit via another balanced
XLR cable. Subsequent slave units will
be connected in the same manner.

PROCESSOR

OUTPUTS

OR

FATHOM REAR CONTROLS (MASTER)

FATHOM REAR CONTROLS (SLAVE)

RECEIVER / PROCESSOR

PRE OUT

REAR CENTER

FRONT

L

REAR

FRONT

R

SUB

TO ADDITIONAL FATHOMS

(IF APPLICABLE)

IMPORTANT

Connections between the “Master” and
“Slave” Fathoms and between “Slave”
Fathoms are via balanced XLR cables ONLY.

WARNING

WARNING! TURN OFF THE FATHOM(S) AND ALL OTHER EQUIPMENT IN
THE SYSTEM BEFORE MAKING OR CHANGING ANY CONNECTIONS!

Page 23 | Fathom f212

STEREO ACTIVE CROSSOVER (BALANCED OUTPUTS)

LOW OUT

(SUB OUT)

FATHOM REAR CONTROLS (MASTER)

STEREO ACTIVE CROSSOVER (UNBALANCED OUTPUTS)

LOW OUT

(SUB OUT)

OR

SYSTEM CONNECTION DIAGRAM 3:
One Fathom in Mono to
Two-Channel Audio System

When connecting a Fathom (or

RIGHTLEFT

multiple Fathoms) in mono to a two­channel audio system you will use both
the “Le or Mono” and the “Right” inputs.
Summing circuitry in the Fathom’s input
section will sum the stereo signals to
mono.

We strongly recommend that you
use a high-quality active crossover
to divide your preampli er’s signals
prior to connection to the Fathom and
to the ampli er driving your main
speakers.  is will allow you to  lter low
frequencies out of the signals driving
the main speakers, resulting in better
performance.

If you are not using an active crossover
and are comfortable running your main
speakers full-range, you can split your
preampli er’s output signals using
appropriate Y-connectors in place of the
active crossover shown in the diagram.

Two connection types are available
for connecting the Fathom to your
two-channel audio system: balanced
(XLR or 1/4-inch TRS connector) and
unbalanced (RCA-type connector).
Balanced connections provide superior
noise rejection and ensure proper
grounding between components. If your
preampli er or active crossover o ers
balanced outputs, we highly recommend
that you use them.

In the connection diagram at le ,
balanced connections are shown as solid
lines, unbalanced connections are shown
dotted. You will only use one of these
input connection methods (not both).

NOTE: If desired, additional Fathoms
can be connected in “Slave” mode to
the Fathom connected as shown on this
diagram. See “Connection Diagram 2” on
page 23 for slave connection explanation.

WARNING! TURN OFF THE FATHOM AND ALL OTHER EQUIPMENT IN THE
SYSTEM BEFORE MAKING OR CHANGING ANY CONNECTIONS!

WARNING

Page 24 | Fathom f212

SYSTEM CONNECTION DIAGRAM 4:
Two Fathoms in Stereo to
Two-Channel Audio System

When connecting two Fathoms in
stereo to a two-channel audio system you
will only use the “Le or Mono” inputs
of each Fathom.  e upper “Input Mode”
switch on each Fathom will be set in the
“Master” position.

We strongly recommend that you
use a high-quality active crossover
to divide your preampli er’s signals
prior to connection to the Fathom and
to the ampli er driving your main
speakers.  is will allow you to  lter low
frequencies out of the signals driving
the main speakers, resulting in better
performance.

If you are not using an active crossover
and are comfortable running your main
speakers full-range, you can split your
preampli er’s output signals using
appropriate Y-connectors in place of the
active crossover shown in the diagram.

Two connection types are available
for connecting the Fathoms to your
two-channel audio system: balanced
(XLR or 1/4-inch TRS connector) and
unbalanced (RCA-type connector).
Balanced connections provide superior
noise rejection and ensure proper
grounding between components. If your
preampli er or active crossover o ers
balanced outputs, we highly recommend
that you use them.

In the connection diagram at right,
balanced connections are shown as solid
lines, unbalanced connections are shown
dotted. You will only use one of these
input connection methods (not both).

NOTE: If desired, additional Fathoms
can be connected in “Slave” mode to
each Fathom connected as shown on this
diagram. See “Connection Diagram 2” on
page 23 for slave connection explanation.

STEREO ACTIVE CROSSOVER (BALANCED OUTPUTS) STEREO ACTIVE CROSSOVER (UNBALANCED OUTPUTS)

LOW OUT

(SUB OUT)

OR

FATHOM REAR CONTROLS (MASTER)

FATHOM REAR CONTROLS (MASTER)

LOW OUT

(SUB OUT)

RIGHTLEFT

WARNING

WARNING! TURN OFF THE FATHOM(S) AND ALL OTHER EQUIPMENT IN
THE SYSTEM BEFORE MAKING OR CHANGING ANY CONNECTIONS!

Page 25 | Fathom f212

RECOMMENDED SETUP PROCEDURES

1) Preparation for Setup Process: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-27

2) Level Setting: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

3) Polarity/Phase Adjustment: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4) Experiment with Location: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5) Apply A.R.O: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-30

6) Adjust E.L.F. Trim: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

PREPARATION FOR SETUP PROCESS:

Please con rm the following system settings before beginning the setup
process.  is will ensure a neutral starting point and an e ective setup of your
subwoofer system.

On your Home Theater Receiver or Preamp/Processor:

Before beginning setup of your Fathom subwoofer system we recommend that
you set your receiver or preamp/processor as follows (please turn o all Fathoms
in the system prior to making these adjustments):

1. Speaker Size

In the speaker setup menu of your receiver or preamp/processor, set up all of
your high-frequency speakers as “small” with a crossover point of 80 Hz.  is
will send ALL bass to the Fathom(s).

2. Speaker Distance

In the speaker setup menu, properly set all speaker distances to the primary
listening seat, including the subwoofer’s distance. Use a tape measure to
determine these distances (time coherence is important.) If multiple Fathoms
are being used, average their distances to the primary listening seat and use
that number to set the subwoofer distance.

3. Subwoofer Level

Set the subwoofer level in the receiver or preamp/processor “0” or its middle
position.

4. Tone Controls / Equalizers

Set all tone controls to “0” and defeat all equalizer features.

On your Active Crossover or Bass Management Processor:

If you are using an active crossover or bass-management processor, we
recommend that you set it as follows before beginning setup of your Fathom
subwoofer system (please turn o all Fathoms in the system prior to making
these adjustments):

1. Low-Pass Filter Frequency

Select a low-pass  lter frequency of 80 Hz (12dB/octave slope)

2. High-Pass Filter Frequency

Select a high-pass  lter frequency of 80 Hz (12dB/octave slope)

3. Low-Pass (Subwoofer) Output Level

Set the subwoofer output level to “0” or its middle position.

Page 26 | Fathom f212

On the Fathom’s Front Panel:

Please turn o the home theater receiver or preamp/processor to make these
adjustm ents.

1. “Power” Switch

Flip each Fathom’s “Power” switch to the “On” position.

2. “Lights” Switch

Flip each Fathom’s “Lights” switch to the “On” position. If you don’t see any
lights on the front panel, you may have forgotten to plug the Fathom in or
there may be a problem with the electrical circuit.

3. “Input Mode” Indicator Lights

If you are using a single Fathom, con rm that its “Input Mode” indicator light
is on the “Master” position. If not, you will need to access the upper “Input
Mode” switch on the rear panel of the Fathom.
If you are using multiple Fathoms in a Master/Slave con guration, con rm
that the unit connected directly to your receiver or preamp/processor is
indicating “Master” on its “Input Mode” lights and that all other units are
indicating “Slave” on their “Input Mode” lights. If not, you will need to access
the upper “Input Mode” switches on the rear panels of the Fathoms.

3. “Level Mode” Switch

Flip the master Fathom’s “Level Mode” switch to the “REF” position.

4. “LP Filter” Switch

If your home theater receiver/processor is handling bass management
(speakers set on “small”) or if you are using an outboard crossover/bass­management processor,  ip the master Fathom’s “LP Filter” switch to “OFF.” If
not, select the “12 dB” position.

5. “LP Freq. (Hz)” Knob

Rotate the “LP Freq.” knob to the “80 Hz” position.

6. “e.l.f. trim (dB)” Knob

Rotate the “e.l.f. trim” knob to “0”

7. “Polarity” Switch

Flip the “Polarity” switch to “0”.

8. “phase (deg.)” Knob

Rotate the “phase” knob to “0” degrees

9. A.R.O. Defeat Switch

Press the A.R.O. defeat switch so that the red light in the
switch remains lit.

Page 27 | Fathom f212

RECOMMENDED SETUP PROCEDURES (continued)

Subwoofer System Setup:

Once you have set the controls on your home theater receiver or preamp/
processor and on your Fathom(s) to the settings recommended on pages 26 and
27, you are ready to begin setting up your Fathom for optimum performance.

1) Level Setting

Using familiar music or movie material with deep bass content, adjust the
subwoofer level to blend with the other speakers using your receiver or preamp /
processor’s subwoofer level control.  is method is more immune to tampering
than using the Fathom’s “Master Level” knob (think toddlers or curious visitors).

In the unlikely event that the subwoofer level control in your receiver or
preamp/processor cannot be turned up enough to level match the Fathom, return
that control to “0”.  en,  ip the Fathom’s “Level Mode” switch to “Variable”
and with “0” as your reference point (REF mode gain and Variable “0” gain are
identical) use the “Master Level” control to level match the subwoofer with the
other speakers. MAKE NOTE OF THIS SETTING FOR FUTURE USE.

For more detailed information on your Fathom’s level setting controls, please refer
to the “Level Mode” and “Master Level” sections on pages 15 - 16 of this manual.

2) Polarity and Phase Adjustment

It is o en helpful to have a second person operating these controls so that you
can easily hear the changes from the primary listening seat.

Listening to familiar source material (preferably music with good upper bass
and midbass response),  ip the “Polarity” switch from “0” to “180” and listen for
di erences.  e correct setting will sound most natural with the best upper bass
punch and articulation. If both sound similar, choose “0”.

Once Polarity is set, use the same music material to audition di erent “Phase”
control settings and choose the one that further enhances the upper and midbass
response. If you can’t hear a di erence, set the control to “0.”

3) Experiment with alternative subwoofer locations (if necessary).

If you are satis ed with the basic performance of your subwoofer you are
ready to move on to the next step. If not, we recommend that you experiment with
the position of your subwoofer until you are pleased with its basic performance.
Experimentating with placement is KEY to a superior sounding system. Moving the
subwoofer just a few feet can have a signi cant e ect on the smoothness of the bass.
For each new position, start with the polarity and phase controls at “0” and repeat the
setup process beginnng with Step 1.

IMPORTANT! WRITE DOWN ALL SETTINGS PERFORMED IN STEPS 1-3 FOR

FUTURE REFERENCE.

Page 28 | Fathom f212

IMPORTANT

IMPORTANT

IMPORTANT! IMPORTANT! MAKE SURE THE ROOM IS QU IET DURING A. R.O.
CALIBRATION! TURN OFF ANY NOISY APPLIANCES NEAR THE LISTENING
ROOM (DISHWASHERS, WASHING MACHINES, ETC.)

IT IS PARTICULARLY IMPORTANT TO TURN OFF AIR CONDITIONERS OR HEAT
PUMPS DURING CALIBRATION. THESE FORCED-AIR-TYPE HVAC SYSTEMS
CAN CREATE MODERATE LEVELS OF 15 – 20 HZ NOISE THAT MAY INTERFERE
WITH CALIBRATION.

DO NOT TALK, COUGH OR SNEEZE DURING CALIBRATION AS THIS MAY
CORRUPT THE CALIBRATION MEASUREMENTS.

4) Applying Automatic Room Optimization (A.R.O.)

You are now ready to apply the power of JL Audio’s exclusive Automatic Room
Optimization system.  is system will measure the response of the subwoofer at
your primary listening seat and apply a powerful equalizer to tame the primary
room mode, resulting in smoother, more accurate bass performance. If you are
using multiple Fathoms in a master/slave con guration, you will only need to
address the unit designated as “master” to perform A.R.O. calibration for the entire
subwoofer system.

a) Set the Main Power switch to the “ON” position and be sure the Fathom’s

indicator lights are switched “ON” via the “Lights” switch.

b) Flip the Fathom’s “Level Mode” switch to “Variable” and turn the Master Level

control to the “12 o’clock” position. If you were already in “Variable” mode, make
a note of the volume position you established during Level Setting (Step 1) before
turning it to the “12 o’clock” position for A.R.O. calibration. In most cases, you
will need to tweak the overall level of the subwoofer a er the A.R.O. calibration is
run, but you need to know your prior setting to begin that process.

c) Set the LP Filter to “OFF”

d) Verify that the “e.l.f. trim” control is set to “0”

e) Remove the calibration microphone from its protective pouch

and connect its cable to the mini-XLR jack on the Fathom’s front control panel.

NOTE: A.R.O. Calibration is only possible when the included JL Audio test
microphone is plugged in to the Fathom front panel.  e “Calibrate” feature is
disabled with no microphone plugged in to prevent accidental loss of settings.

f) Connect the microphone to the other end of the mic cable and temporarily place

the mic in the primary listening seat. If you have a microphone stand, you can
place the microphone at head height and position in the primary listening seat.

g) On the Fathom’s control panel, press the “Calibrate” button.  e green light on

the “Calibrate” button will turn on, indicating that calibration will begin in 5
seconds.

NOTE: If you have already run A.R.O. once, the “Calibrate” light will already be on.
Each time A.R.O. calibration is run, the previous settings are erased and the new
settings are stored.

Page 29 | Fathom f212

h) Within 5 seconds of pressing the “Calibrate” button, return to your primary

listening seat and hold the microphone in your normal, seated head position at
the approximate height of your ears.

i) A series of quick, stepped tones will begin which are used by the A.R.O. so ware

to set an appropriate bass level at your seat for the test. If these tones stop a er
two to  ve cycles, the “Calibrate” button’s light will start to blink, indicating a level
setting error.
Slow blinking (approximately once per second) indicates the level selected
on the “Master Level” control was too low. Increase the Master Level control
approximately one eighth of a turn and go back to Step “g”.
If the Calibrate light is blinking quickly (approximately 3 times per second), this
indicates that the “Master Level” was set too loud. Decrease the Master Level
control by approximately one eighth of a turn and return to Step “g”.

j) When the “Master Level” is properly set, a slow series of tones will be played from

20 Hz to 100 Hz a er the stepped, level-setting tones. During this process, the
A.R.O. system is taking a frequency response measurement at your listening seat.
When A.R.O. is  nished calibrating, the “Calibrate” button will light and stay on,
indicating a successful calibration.

k) Return your Fathom’s front panel controls to their previously determined settings

(before the A.R.O. calibration run) and re-tweak the subwoofer output level as
described in Step 1 (Level Setting) on page 28. Since the A.R.O. will smooth the
largest peak in the bass response at the listening seat, the apparent subwoofer level
may appear lower. Simply increase the subwoofer level until you are satis ed.

IMPORTANT! IF YOU MOVE YOUR FATHOM OR PRIMARY LISTENING SEAT
IN THE FUTURE, YOU WILL NEED TO RUN A.R.O. AGAIN. ANY PARTICULAR
CALIBRATION IS UNIQUE TO THAT PARTICULAR SUBWOOFER POSITION
AND LISTENING SEAT POSITION COMBINATION. SIMPLY FOLLOW THE
STEPS ABOVE TO CREATE A NEW CALIBRATION CURVE.

5) Extreme Low Frequency (e.l.f.) Trim

Use the “e.l.f. trim” control to adjust the extreme low bass extension of the
Fathom.  is control allows -12 dB of cut or +3 dB of boost at 25 Hertz and is
particularly useful when using a Fathom (or two) in a small to medium sized home
theater. Since smaller enclosed spaces help to boost the level of the lowest bass
frequencies, smaller theaters can be overwhelmed by the strong low-bass output
of the Fathom subwoofer.  is can create a “thick” or “bloated” character in the
lower bass region. Turning down the “e.l.f. trim” knob cuts the extreme low bass
level and alleviates this condition. Feel free to experiment and listen to a variety of
demanding material until you  nd the best match for your room and your tastes.

Your Fathom is now optimized for maximum bass performance at your
listening seat. Congratulations!

IMPORTANT

Page 30 | Fathom f212

FREQUENTLY ASKED QUESTIONS

Can I place objects on my subwoofer?

We do not recommend placing any items on the subwoofer cabinet as they may
vibrate, causing undesirable noise and possible damage to the  nish. Under no
circumstances should any object containing liquid be placed on the Fathom cabinet.

Is the Fathom magnetically shielded?

Fathom subwoofers are not magnetically shielded. To avoid magnetic distortion
with certain television types, place the Fathom at least 3-4 feet (1 - 1.5m) from
your screen. If you notice any discoloration in the picture, try moving the
subwoofer further away until these artifacts disappear.

Will my electric bill be high if I leave the Fathom in “Auto” mode?

When in “Auto” mode, the Fathom ampli er is only powered up when a
signi cant signal is detected on the inputs. When powered down, only
“housekeeping” circuits remain on, which draw negligible amounts of power
from the wall (less than 5 watts).

Should I unplug my subwoofer during a thunderstorm or extended absence?

YES. You should unplug your Fathom during (or before) thunderstorms.  is
will prevent any possible damage from voltage spikes due to lightning. In these
conditions, it’s a good idea to unplug all of your audio / video components. If you
are going to be away from home for several days, it is also a good idea to unplug
your home theater components to prevent damage from unexpected storms or
power line conditions.

Page 31 | Fathom f212

CLEANING YOUR FATHOM

Dust your Fathom subwoofer’s cabinet using a clean, so micro ber cloth or
feather duster. Micro ber cloths are commonly available where automotive
detailing supplies are sold.

Gloss-black models:

Light smudges can generally be wiped o with a clean micro ber cloth. For more
stubborn smudges, polish and protect the  nish using a high-quality automotive
wax and a micro ber cloth, both available wherever automotive detailing
supplies are sold. We recommend Meguiar’s® “NXT Tech Wax” and Meguiar’s®
Micro ber Detailing cloths.

Never use a polish that contains harsh solvents or abrasives as these may
permanently damage the  nish. Never use furniture polish or any oil-based
product on your Fathom. Never use solvents or aggressive cleaning agents on
your Fathom. When in doubt, test the cleaning product on the underside of
the cabinet and let it sit for several days before committing to its use on visible
portions of the cabinet.

Page 32 | Fathom f212

TROUBLESHOOTING

No sound from subwoofer.

1. Verify that Fathom is plugged in, turned “ON” & that front panel lights are
“ON”. If the Fathom will not power up, check the circuit breaker that feeds its
outlet.

2. Test subwoofer using DEMO button on front panel – if sub emits demo
tones the subwoofer’s internal circuitry is  ne and an input problem is likely.
Check the input cable connections at the Fathom and at the receiver/preamp/
processor.

3. Verify that your receiver’s subwoofer settings have not changed

4. If your other speakers play, but the Fathom does not, try changing the cable
that connects the Fathom to the system.

5. If the problem persists, call your dealer or JL Audio Technical Support for
assistance.

 e bass level has changed.

1. Make sure your level settings (on the Fathom and in your receiver/preamp/
processor) have not changed.

2. If you are using the Fathom’s “Master Level” knob to set the subwoofer level,
con rm that the “Level Mode” switch is set to “Variable”.

3. Verify the position of the ELF Trim knob.

Hums or other unusual noises from your Fathom

1. See Input Mode discussion on page 20 of this manual, especially if any
upstream components, cables, etc., have recently changed.

2. Turn o the Fathom, disconnect all its input and output signal cables, turn the
Fathom back on. If the noise disappears, the noise is being caused elsewhere in
your system.

Bass sounds “muddy” or “too heavy”.

1. Try decreasing the 25 Hertz level using the “e.l.f. trim” control. Muddy bass
can sometimes be caused by too much low frequency output in a moderately
sized room.

2. Decrease the overall subwoofer level.

3. Verify your receiver’s subwoofer settings.

4. Try a di erent subwoofer or main listening seat location. Changing one or the
other can have a HUGE e ect on how your system sounds. See the placement
discussion on pages 6-10 of this manual.

Your Fathom is clearly audible outside of your house.

1. Revisit the “Master Level” setting on your Fathom(s) or your home theater
receiver/preamp/processor.

2. Inquire with your JL Audio dealer about noise isolation strategies.

3. Move the Fathom away from windows.

Angry neighbors knocking at your door.

Invite them in and o er them a beverage.

Page 33 | Fathom f212

Page 34 | Fathom f212

LIMITED WARRANTY / SERVICE INFORMATION

JL AUDIO warrants this product to be free of defects in materials and

workmanship for a period of three (3) years from the original date of purchase.

Damage caused by the following is not covered under warranty: accident,
misuse, abuse, product modi cation or neglect, failure to follow installation
instructions, unauthorized repair attempts, misrepresentations by the seller.  is
warranty does not cover incidental or consequential damages and does not cover
the cost of removing or reinstalling the unit(s) or shipping the unit(s) to JL Audio
for service. Cosmetic damage due to accident or normal wear and tear is not
covered under warranty.

 is warranty is not transferable and applies only to the original purchaser
of the product from an authorized JL AUDIO dealer. Warranty is voided if the
factory-applied product serial number is removed or defaced.

Should service be necessary under this warranty for any reason due to
manufacturing defect or malfunction, JL AUDIO will, at its discretion, repair or
replace the defective product with new or remanufactured product at no charge.

Any applicable implied warranties are limited in duration to the period of
the express warranty as provided herein beginning with the date of the original
purchase at retail, and no warranties, whether express or implied, shall apply
to this product therea er. Some states do not allow limitations on implied
warranties, therefore these exclusions may not apply to you.  is warranty gives
you speci c legal rights, and you may also have other rights which vary from
state to state.

WARNING

WARNING: THIS PRODUCT CONTAINS NO USERSERVICEABLE PARTS.

PRODUCT IN WHICH DISASSEMBLY, REPAIR AND/OR MODIFICATION HAS

BEEN ATTEMPTED BY UNAUTHORIZED PARTIES WILL NOT BE COVERED

UNDER WARRANTY.

If you need service on your JL AUDIO product:

All warranty returns should be sent to JL AUDIO freight prepaid through
an authorized JL AUDIO dealer and must be accompanied by proof of purchase
(a copy of the original sales receipt.) Direct returns from consumers or non­authorized dealers will be refused unless speci cally authorized by JL AUDIO
with a valid return authorization number. Warranty expiration on products
returned without proof of purchase will be determined from the manufacturing
date code. Coverage may be invalidated as this date is previous to purchase date.
Return only defective components. Non-defective items received will be returned
freight-collect. Customer is responsible for shipping charges and insurance in
sending the product to JL AUDIO. Freight damage on returns is not covered
under warranty. Always include proof of purchase (sales receipt).

For Service Information in the U.S.A. please call:

JL Audio customer service:
[phone] during normal business hours (Eastern Time)
JL Audio, Inc • 10369 North Commerce Parkway, Miramar, FL 33025

International Warranties:

Products purchased outside the United States of America are covered only by that
country’s distributor and not by JL Audio, Inc.

Page 35 | Fathom f212

FEATURES

Unbalanced Inputs:

Stereo or Mono (two RCA jacks)

Balanced Inputs:
Stereo or Mono (two female XLR jacks)

Output To Slave:

Balanced (one male XLR jack)

Input Modes:
Master or Slave

Level Modes:

Reference ( xed gain) or Variable from
full mute to +15dB over reference gain

Power Modes:
O , On or Automatic Signal-Sensing

Light Modes:

O , On or Dim

Low Pass Filter Mode:
O , 12 dB per octave or 24 dB per octave

Low Pass Filter Cuto Frequency:

Variable from 30 Hz – 130 Hz

Polarity:
0 or 180 degrees

Phase:

H

Variable from 0 – 280 degrees

E.L.F. Trim:
Variable from –12 dB to +3 dB at 25 Hz

Automatic Room Optimization (A.R.O.)

with included laboratory-grade
calibration microphone, defeatable.

Specifications

Dimensions: (H) Height x (W) Width x (D) Depth

SKU-011262-09-2008

W

Enclosure Type: Sealed

Driver: Dual 12-inch (no minal diameter)

Frequency Response (anechoic):

Effective Piston Area: 168 sq. in. / 0.1084 sq. m.

Effective Displacement: 574 cu. in. (9.4 liters)

Amplifier Power: 3000 watt s RMS short-term

Height Dimensions include feet.

Net Weight: 220 lbs. (100 kg)

Cabinet Finishes:

f212

fathom home subwoofer

20 - 97 Hz (+/- 1.5 dB)

-3 dB at 19 / 110 Hz

-10 dB at 15 / 157 Hz

31.96 in. x 14.92 in. x 20.39 in.
812 mm x 379 mm x 518 mm

High- Gloss Black or Satin B lack

D

HOME AUDIO | MOBILE AUDIO | MARINE AUDIO

“JL Audio”, “Fathom” and the JL Audio logo are registered trademarks of
JL Audio, Inc., “Ahead of the Curve” is a trademark of JL Audio, Inc. Due to
continuous product development, all specifications are subject to change
without notice.

Printed in USA • ©2008 JL Audio, Inc. • U.S. PATENTS: #5,734,734 #5,949,898
#6,118,884 #6,229,902 #6,243,479 #6,294,959 #6,501,844 #6,496,590
#6,441,685 #5,687,247 #6,219,431 #6,625,292 #D472,891 #D480,709 Other
U.S. & Foreign patents pending. For more detailed information please visit us
online at www.jlaudio.com.

www.jlaudio.com

 North Commerce Parkway • Miramar, Florida •  • USA