SABINE FBX 2020 Plus User manual

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FBX and FBX Feedback Exterminator are registered trademarks of Sabine, Inc., and are the brand names of its line of automatic feedback controllers. Covered
by U.S. Patent No. 5,245,665, German Patent No. 69118486.0, U.K. Patent No. 0486679, Australian Patent No. 653,736, and Canadian Patent No. 2,066,624-2.
ClipGuard™ adaptive clip level control is covered under U.S. Patent No. 5821889. Other patents pending.
Operating
Guide
INSIDETHISGUIDE:
About the FBX2020-Plus 1-2
FBX2020-Plus Controls 3
Applications 4-5
UnderstandingFixed
& Dynamic Filters 6
OperatingInstructions 6-8
TroubleshootingTips 8
Product Specifications 9
Block Diagram 9
Cautions & Warranty 10
ComplianceInformation 11
Special features of the FBX2020-Plus:
• The FBX2020-Plus is a dual-channel unit with an improved algorithm that allows it to better distinguish the difference
between feedback and music.
• It has improved 20-bit digital resolution, providing superior dynamic range and signal-to-noise ratio.
• The FBX2020-Plus has 12 feedback filters per channel, giving the unit more feedback elimination power for the toughest
venues.
• TheFBX2020-Plus'snew ClipGuard® adaptive cliplevelcontrol,with TURBO set-upmode,increasesthe effective dynamic
range by more than 10dB and makes set-up faster and easier.
• The FBX2020-Plus now includes a Dynamic Filter Reset option.
• The FBX2020-Plus incorporates an internal power supply.
• Standard FBX features such as lockable fixed filters and switchable 1/10- and 1/5-octave constant "Q" filters are also
included.
CONGRATULATIONS! You now have the state-of-the-art in feedback control. Your Sabine FBX2020-Plus Dual Feedback
Exterminator, a dual-channel, 20-bit digital filtering device that gives you automatic real-time feedback control and increases
the clarity and volume of your system.
The FBX2020-Plus incorporates the latest in digital signal processing technology. It automatically senses feedback in a sound
system and determines its pitch. It then places one of 12 constant "Q" micro-filters on the resonating frequency and eliminates
the feedback in typically less than one second.
QUICK-START OPERATION
For best results, read all operating instructions before using the FBX2020- Plus . If you're
already familiar with the FBX or just want a basic overview of FBX operation, this simple
quick-start procedure is for you. More detailed instructions are on page 7 inside this
operating guide.
1. Place the FBX between the output of your mixer and the input of your power amp.
2. With the mixer master volume down, put one FBX2020-Plus channel in active mode
(red BYPASS LED off), then slowly raise the mixer master volume to the point of
feedback.
3. Keep raising the master volume until all of your fixed filters and one dynamic filter are
set, then lower the volume slightly. The rest of the filters catch new feedback
frequencies throughout the program.
4. Repeat this procedure for the other FBX2020-Plus channel, & you're ready to go.
READTHEENTIREOPERATING GUIDE FORCOMPLETEINSTRUCTIONS.
©2003 Sabine, Inc.

2
ABOUT THE FBX2020-Plus
FREQUENCY RESPONSE: FBX 1/10-Octave Filter Vs. 1/3-
Octave Graphic EQ Filter (12 dB depth; Log Scale).
A DIRECT HIT ON FEEDBACK! The FBX targets feedback without
taking a big chunk out of your sound. Tests prove that a single 1/3-
octave EQ slider pulled down 12 dB removes almost half the power
going to the speakers over a two-octave range. And, as this illustra-
tion shows, you can't place a graphic EQ filter precisely on the ringing
frequency. When you pull down multiple sliders in a normal setup
(below), you end up with giant holes in your music. On the other hand,
FBX micro-filters are 10 times narrower - you get back up to 90% of
the power you lose with a graphic EQ! That means more gain before
feedback and no loss in sound quality.
FREQUENCYRESPONSE:
Full Set-Up FBX Vs. 1/3 Octave Graphic Equalizer. Test
procedure: A PA system was set up using a microphone,
mixer, FBX, power amp and two speakers. The system's
gain was raised until the FBX removed nine feedback points.
Next, the FBX was replaced with a 1/3 octave graphic EQ.
The EQ was adjusted while the system gain was raised to
the same level achieved with the FBX. The frequency
response curves of each device were then plotted.
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WORLD'SBESTFEEDBACKCONTROLLER:
Before the invention of the FBX, the most common device for controlling feedback was the 31-band graphic EQ. However, the
FBX has three distinct advantages. The most obvious is that the FBX functions automatically, even during the program. Second,
the FBX micro-filters are precisely placed while EQ filters are fixed. The difference: FBX filters do not have to be as deep or wide,
so there is more system gain. The third most important advantage is that FBX micro-filters are ten times narrower than 31-band
EQ filters. FBX micro-filters return up to 90 percent of the power removed by EQ filters.
Over the years, engineers stopped using 12-band EQs in favor of the narrower-filter 31-band EQ for controlling feedback. The
FBX represents the next step. An EQ would need more than 10,000 sliders to be equivalent to your FBX. With the FBX2020-
Plus, your monitors will finally sound loud enough, everyone in the audience will understand each word, and the mains will
sound natural and transparent.
WHO NEEDS THE FBX?
Virtually every sound system will be improved with the FBX. Small bands that do not have sound technicians can now increase
their monitor volumes so they can hear themselves clearly and with full fidelity - without worrying if the program is going to be
ruined by feedback.
Auditoriums and churches of all sizes will enjoy reliable feedback control. Hotels and conference centers around the world can
offer meeting rooms with sound systems that won’t howl during programs. The FBX2020-Plus can be installed in theaters,
schools, sports arenas, courtrooms -- anywhere multiple microphones are used. It can also be used for teleconferencing,
intercoms or interactive remote classrooms.
WHY THE FBX?
The simple beauty of the FBX is its ability to quickly and effectively eliminate feedback with narrower filters than ever before
possible. The FBX delivers superior sound quality automatically.

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FRONTPANEL
ACTIVE/BYPASS
Bypass mode takes the unit out of
the signal path so that it will have
no effect on the program. In active
mode, the unit controls feedback
automatically. The red BYPASS
LED lights when the unit is in
bypass mode.
FIFTHOCTAVE
Press the button at any time to
select wider filters for any new
filters to be set. It is possible to
have both 1/5 and 1/10 octave
constant "Q" filters active in one
channel simultaneously.
RESET
Press and hold until 'Dynamic Filter'
LEDs go out to reset the dynamic
filters. Hold until all LEDs go out to
reset all filters. This also
automatically places the unit into
Turbo mode.
SIGNALLEVEL
The LED ladder indicates the signal
strength relative to the FBX's input
clip level.
FBX2020-Plus CONTROLS
A/CPOWERINPUT
The FBX2020-Plus is factory configured to operate at either 115
VAC or 230 VAC. Using the wrong input voltage may cause
permanent damage to the unit and will void the warranty.
FUSES
This equipment is fitted with an IEC power inlet incorporating a built-
in fuse holder. To change the fuses in this socket:
1. Disconnect the power cord from the unit.
2. Pull out the fuse holder and remove the old fuse.
3. Install a new fuses into the holder. Replace only with 5x20mm,
0.315A, 250V F (fast acting) fuses.
4. Refit the fuse cover.
FILTERSTAGEACTIVITY
When one of the unit’s filters is
activated, the corresponding LED
lights. A blinking LED indicates the
filter that was most recently
activated.
POWERSWITCH
The ON/OFF switch is a two-
position push button switch. The
power indicator LED will light
when the FBX is operational.
SETTOTALNO.
To set the total number of filters,
depress the button for 4 seconds
and then release. The LEDs will
begin to light in sequence. When
the LED corresponding to the
desired number of filters lights,
press the button to register your
selection. This also automatically
puts the unit into Turbo mode.
SETFIXED
To set fixed filters, hold down the
button for 4 seconds and then
release. The LEDs will begin to
light in sequence. When the LED
corresponding to the desired
number of fixed filters lights, press
the button to register your
selection.
LOCKFIXEDFILTERS
When the "LOCK FIXED" button is
pressed, its LED will light to
indicate that the FBX is in "LOCK
FIXED"mode. "LOCKFIXED"mode
can be activated at any time after
system set-up and will stay on
until the button is pressed again
and the LED turns off.
INPUTSANDOUTPUTS
1/4" TRS and XLR balanced and unbalanced.
GROUNDLIFT
Use this switch to choose between grounded or lifted ground.
BACKPANEL
TURBOMODE
Turbo Mode is designed to allow maximum
feedback sensitivity for setting fixed filters
during setup only. This default setup mode
allows the FBX to grab feedback much
faster and at a much lower level, making
setup faster and quieter. When a channel
of the 2020Plus is in Turbo mode, the clip
levellightflashes. DONOTENTERTURBO
MODEDURINGAPERFORMANCE.

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FBX SET-UP FOR MONITORS:
CHB-OUT CHB-IN
CHA-IN
CHA-IN
CHB-IN
FBX SET-UP FOR ENTIRE MIX:
APPLICATIONS
CHB-OUT
CHA-OUT
CHA-OUT
AMP
AMP
Mix 1
Mix 2
MIXER
All other
signal processing
equipment
All other
signal processing
equipment
AMP
AMP
Right Send
Left Send
MIXER

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MIXER Input
Channel 2
Use 1/4" TRS plug for balanced sends/inserts.
Use 1/4" TS plug for unbalanced sends/inserts.
MIXER Input
Channel 1
HIGH Z
LOW Z
INSERT
RETURN INSERT
SEND
HIGH Z
LOW Z
INSERT
RETURN INSERT
SEND
FBX SET-UP FOR SINGLE INSERT POINT:
CHA-OUT CH A - INCHB-OUT CH B - IN
FBX SET-UP FOR INSERT SEND & RETURN:
MIXER Input
Channel 2
HIGH Z
LOW Z
INSERT
MIXER Input
Channel 1
HIGH Z
LOW Z
INSERT
Insert Y-cord
1/4" TS plug
(R) 1/4" TS plug
(T)
1/4" TRS plug
CHB-OUT CHB-IN CHA-INCHA-OUT
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67
Before You Begin
The FBX automatic feedback controller will improve any sound
reinforcement system. By following these suggestions, you will
be assured of the most benefit from your FBX enhanced sound
system. The instructions presume that you are familiar with the
fundamentals of sound reinforcement.
Where the FBX fits in your sound system:
Place the FBX anywhere in the sound system that a graphic
equalizer might be used to control feedback. The most com-
mon place is between the output of the mixer and the input of
a power amp. In this position, the FBX can sense and eliminate
feedback occurring in any channel of the mixer. The FBX can
also be used on a mixer insert point for a single channel, or a
sub-group (see diagrams on pages 5-6).
Note: If you’re using a mixer with unbalanced 1/4" outputs, you
must use standard unbalanced cables and connectors when
connecting it to the FBX. Similarly, if your mixer is wired for
balanced 1/4" (Tip/Ring/Sleeve) outputs, you must use that
typeof connector. If you don’t, you may experience a loss of gain
when using the FBX.
The FBX is designed for balanced output. If either side of the
balanced output is grounded at any point, a 6 dB loss in
dynamic range may occur (+21 dBV max. signal level unbal-
anced; +27dBV max. signal level balanced).
A note about graphic equalizers:
The FBX is designed to replace the graphic
equalizer’s function for eliminating feedback. In
many applications, such as churches, auditoriums
or small acoustic ensembles, the mixing board
provides all the tonal control that is necessary. The FBX can
replace the graphic EQ altogether in some applications, how-
ever, a graphic equilizer may be beneficial to shape a system's
total performance.
If you do want to use an equalizer, place the FBX after the EQ
in the signal path. Use the EQ’s controls to shape the tonal
response of the sound system, but DO NOT NOTCH FOR
FEEDBACK.
UnderstandingFIXEDandDYNAMICfilters:
Before operating the FBX, you need to understand
the two types of FBX filters: FIXED and DYNAMIC.
FIXED FILTERS retain their frequency center-points
until the unit is reset by the user. The system’s gain before
feedback is limited primarily by the number of fixed filters; i.e.,
increasing the number of fixed filters increases the system’s
gain before feedback. The FBX's DYNAMIC FILTERS control
intermittent feedback that comes and goes throughout the
program. They are continually reset automatically to different
frequencies as new feedback occurs during the program. For
mostapplications,theoptimalsettingisnine FIXED andthree
DYNAMICFILTERS. Thisis thefactorydefault.
ClipGuard®AdaptiveClipLevelControl:
Your FBX2020-Plus has a powerful new feature: Sabine's
patented ClipGuard®adaptive clip level control. Until Sabine
invented ClipGuard®, engineers had to set audio equipment
input and output levels to a compromised setting that allowed
too much noise in quiet programs and risked clipping during
high-level programs. With ClipGuard®, no front panel program
level control is needed. It automatically matches the FBX2020-
Plus internal dynamic range to the constantly changing pro-
gram level and maintains unity gain. ClipGuard®extends the
effective dynamic range of your FBX2020-Plus from 100dB to
105dB!
OPERATING INSTRUCTIONS
ClipGuard®incorporates TURBO mode setup, another new
feature. It cuts the time for FBX filter initialization to just a few
seconds, and it greatly reduces the volume level of the feed-
back during setup. The FBX2020-Plus is set in TURBO mode
at the factory and automatically engages every time you
press RESET or SET TOTAL NO. (to reset filters or set total
number of filters). The FBX2020-Plus automatically returns
to normal program mode when the first dynamic filter is set
or when you press the front panel LOCK FIXED button. ALL
FILTERLEDS WILL CYCLETO INDICATE THEFBX IS ABOUT
TO EXIT TURBO MODE.
NOTE:
If you press LOCK FIXED to turn off TURBO mode
before all the fixed filters have been set, and you want to use
the rest of the fixed filters, press LOCK FIXED again right away
-- before a dynamic filter sets. Once a dynamic filter sets, you
will not be able to use the rest of the fixed filters unless you reset
and reinitialize the unit.
WARNING: Followthesetupprocedureoutlined in the next
section,anddonot playprogramduringTURBOset-upmode.
Otherwise,theFBX2020-PluswillclipandmaysetFBX filters
improperly. (Clip level is set to the lowest level so the feedback
clips quickly; therefore, your program will also be clipped in
TURBO mode. Be sure a dynamic filter is set, and if one isn't,
press the LOCK FIXED button before your program begins.)
You'll know the 2020Plus is in TURBO mode if the red CLIP LED
flashes when no other signal level LEDs are on.
NOTE: Any loud sounds picked up by open micrphones while
TURBO is engaged may cause FBX filters to set. For this
reason we recommend maintaining silence as much as
possible during the short time TURBO is engaged.
If your venue is too noisy to take advantage of TURBO mode,
turn off TURBO by pressing LOCK FIXED on, then off before you
initialize for feedback. Remember: if you leave LOCK FIXED on,
the fixed filters won’t initialize. The LED indicating LOCK FIXED
should be off when initializing.
READ THIS
READ THIS
TURBO mode speeds up the FBX filter initial-
ization process so that it takes only a few
seconds, and it greatly reduces the volume
level of the feedback during setup.
If the red CLIP LED flashes when no other
signal level LEDs are on, TURBO is on.
TURBO turns off automatically after the first
dynamic filter is set, or you can turn it off
manuallybypressing theLOCKFIXED button.
(Press it again to unlock the filters.)
NO! TURBO mode should be turned off either
automatically or manually before your pro-
gram begins. If left on, the 1020Plus will clip,
may set FBX filters improperly.
If you press LOCK FIXED to turn off TURBO
mode before all the fixed filters have been
set, and you want to use the rest of the fixed
filters, press LOCK FIXED again right away
before a dynamic filter sets. Once a dynamic
filter sets, you will not be able to use the rest
of the fixed filters unless you reset and start
the initialization again.
What is TURBO
mode?
Why won't all the
fixed filters set?
Can the 1020Plus
work during the
program with
TURBO on?
How do I turn off
TURBO?
How do I know
TURBO is on?
ClipGuard®TURBO Mode Guide

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9. Now lower the master volume slightly so that the system
is not on the verge of another feedback point. This is the
maximum volume level that the FBX will be able to provide.
Higher levels will cause uncontrollable feedback.
10. We recommend you press LOCK FIXED to lock the Fixed
filters at their current depth. See the Features section
below for a complete explanation.
11. ChannelsAandB mustbesetindividuallyandseparately.
To set the second channel, turn down the volume for the first
channel, then bypass the first channel and repeat this
system initializing procedure.
12. You’re ready to go. Make sure TURBO mode is off (clip LED
not flashing). ClipGuard™will automatically match the
input level to the best internal dynamic range.
How To Use FBX2020-Plus Features
Usingthe“LOCK FIXED” feature:
In rare situations the FBX may mistake music for feedback and
drive the fixed filters deeper than necessary, such as in a church
with a pipe organ or during a performance with a great deal of
intentional sustained electric guitar feedback. You can prevent
the fixed filters from deepening beyond their preset depth by
pressing the “LOCK FIXED”button on the front panel. The
“LOCK FIXED”LED will light to indicate that the FBX is in “LOCK
FIXED”mode. The fixed filters will stay locked until you press
the “LOCK FIXED”button again. The dynamic filters are not
affected.
Selecting filter width:
If you’re using the FBX for a music application, the standard 1/10-
octave constant “Q”filter is most effective. However, in spoken
word applications, such as lectures or teleconferencing, we
recommend using the wider 1/5-octave filter for more robust
feedback control. You may enable the 1/5-octave filters by
pressing the “FIFTH OCTAVE”button, and the built-in LED will
light. Only filters set after pressing the button in will be 1/5-octave.
Press the button again to set subsequent filters to standard 1/10-
octave filters.
Important Operating Considerations
Memory:
The FBX stores the positions and depths of the filters in
nonvolatile internal memory when the unit is turned off or during
a power failure. The unit will return all filters to their previous
frequencies and depths when it is turned back on.
BypassMode:
The FBX has a true power-off bypass. The signal is unaffected
in BYPASS MODE even if the unit is turned off. Please note that
if a combination of BALANCED and UNBALANCED inputs and
outputs is used, the signal may be disconnected or attenuated
inBYPASS MODE.
Resetting the filters:
You must reset the FBX if the microphones or speakers are
moved significantly. To reset the unit, place the PA system’s
master volume to minimum and then press the reset button until
all the FILTER LEDs stop flashing. Then follow the system
initialization procedure explained previously. Or you can reset
only the Dynamic filters by pressing and releasing the reset
button after the Dynamic filter LEDs stop flashing. This may be
useful in certain situations, for example, after extensive wireless
microphone use.
Reset Options
The Reset button has two functions: You can reset all the FBX
filters, or just the Dynamic Filters. Hold the reset button in and
all the filter LEDs will begin flashing. To clear only the Dynamic
filters, release the Reset button when the Dynamic filter LEDs
go off (after three flashes). To clear all the filters, do not release
the Reset button until all the filters LEDs go off. A full reset is
recommended whenever you change speaker or microphone
positions. NOTE: Factory default is 9 Fixed and 3 Dynamic
filters, so if you reset Dynamics only those three lights will go
out during reset. And remember, whenever you perform a full
reset you will automatically be in TURBO mode.
WARNING:
Do not reset all filters during the program. This
releases all the feedback you eliminated during setup.
Use
extreme caution
when resetting the Dynamic filters, because
you may need those filters at that moment during the show.
How To Operate The FBX2020-Plus
Follow these steps to obtain the maximum gain before feed-
back without changing the tonal quality of your program.
(Important note: Set up only one channel at a time. Do not
attempt to ring out both channels of your sound system for
feedback simultaneously.)
11. Place the speakers and microphones in the positions
where they will be used during the program. Avoid placing
microphones directly in front of speakers.
12. Place both FBX channels in BYPASS mode.
13. Set the mixer's master volume controls to their lowest
positions. Turn on the mixer, then the FBX, then any other
accessories and finally the power amp. If you are using a
graphic EQ, adjust only for the desired tonal qualities, but
DO NOT NOTCH FOR FEEDBACK. Adjust the balance for
each mixer channel, and set the sound system’s master
volume to minimum.
14. PressRESETfor 3LEDflashes toclear dynamic filters,and
an additional 4 flashes to clear ALL filters set previously.
5. OPTIONAL: Set the total number of FBX filters. (Factory
default is 12 filters per channel - skip to #7 if default is OK
for your application) You can limit the number of available
FBX filters. Hold down the SET TOTAL NO. button for 4
seconds. The LEDs will flash 4 times. Release the SET
TOTAL NO. button. The LEDs will begin to light in se-
quence. When the LED corresponding to the desired
number of filters lights, press the SET TOTAL NO. button.
You've successfully set the total number of filters.
6. OPTIONAL: SetthenumberofFixedfilters(Factorydefault
is 9 fixed and 3 dynamic per chan-
nel - skip to #7 if default is OK for
your application). Depress the
SET FIXED button for 4 seconds.
The filters LEDs will flash 4 times
and then go out. Release the SET
FIXED button, and the LEDs will
begin to light in sequence. When
the LED corresponding to the de-
sired number of Fixed filters lights,
press the SET FIXED button. You’ve successfully set the
number of fixed filters. The remaining filters will be your
dynamic filters.
7. Press the Bypass button to put the FBX in active mode for
the channel you want to set (red LED off).
8. Slowly raise the sound system’s master volume for the
channel being set until feedback occurs. The FBX will
quickly remove the feedback. The first FILTER LED will then
blink to indicate a filter has been set. Repeat this procedure
until all of the FIXED FILTERS and one of the DYNAMIC
FILTERS are set. TURBO setup mode goes off automati-
cally.
IMPORTANTTIP:
You can mix 1/10- and 1/5-
octave filters in the same
channel. If you have an espe-
cially bad feedback problem,
try making the first few filters
1/5-octave and the remain-
ing filters 1/10-octave.

8
TURBO MODE SETUP
The FBX2020-Plus incorporates TURBO mode setup, which is
indicated by a flashing red “CLIP”LED. This lightning-quick
setup feature cuts the time for FBX filter initialization to just a few
seconds, and it reduces the volume level of the feedback
during setup. The 2020Plus is set in TURBO mode at the
factory and automatically engages every time you press
RESET (resetting filters). The 2020Plus automatically re-
turns to normal program mode when the first dynamic filter
is set or when you press the front panel LOCK FIXED button.
ALL FILTER LEDS WILL CYCLE TO INDICATE THE FBX IS
ABOUTTOEXITTURBO MODE.
WARNING: TURBOModewillcausedistortioninyouraudio
program — it is for setup only. You must follow the setup
procedure outlined in the previous section, and do not play
program during TURBO setup mode. Otherwise the 2020Plus
will clip, and filters may be set improperly. (Clip level is set to
the lowest level so the feedback clips quickly; therefore, your
program will also be clipped in TURBO mode. Be sure a dynamic
filter is set, and if one isn’t, press the LOCK FIXED button before
your program begins.) You’ll know the 2020Plus is in TURBO
mode if the red CLIP LED flashes when no other signal level
LEDs are lit.
You can manually override TURBO mode if necessary: Press
LOCK FIXED (the LOCK FIXED light will turn on), then press it
again. (LOCK FIXED light will go out).
MOBILE vs. STATIONARY
MICROPHONES
One significant advantage offered by the Sabine family of FBX
feedback eliminator products is their ability to adapt to chang-
ing acoustical relationships involving sound system compo-
nents and various user applications. One major source of
potential feedback problems arises in situations with wireless
microphones, when the user of the wireless mic is moving
around the stage/auditorium. As a microphone moves in a
sound space, with varying degrees of proximity to the speakers
and varying acoustic responses, feedback frequencies may
shift. In such a situation, feedback-free mobility may be more
important a concern than maximum system gain.
One method of setting FBX filters with mobile microphones is
to turn a microphone on and walk around to the various
possible microphone locations. At the same time, raise the
system gain and set the FBX filters one at a time.
In some situations, raising the number of dynamic filters
(versus fixed FBX filters) may allow a second layer of defense
against new feedback from new locations. However, in many
mobile microphone set ups, fixed FBX filters will protect against
feedback across the range of microphone mobility.
Q. Can I place the FBX in the mixer’s EQ loop?
A. Yes.
Q. Can I place the unit in the mixer effects loop?
A. Avoid this configuration. You can configure the system this way
only if each effects send of each mixer channel is set so that
all of the signal is routed completely through the effects loop.
You cannot mix dry signal with effects signal and still control
feedback.
Q. The signal input LEDs do not light. The unit will not catch
feedback. Why?
A. The unit is not in the signal path. Check the connections. Be
sure that the program is interrupted when the input is discon-
nected from the back of the unit.
Q. Can I mix balanced and unbalanced inputs and outputs?
A. Yes. An unbalanced input and balanced output is compatible.
However, a balanced input and unbalanced output may result
in a 6 dB loss of dynamic range, and the bypass function may
not operate correctly.
Q. WhydoesoneoftheFILTER ACTIVITYLEDsblink?
A. The last filter to be automatically updated blinks. During
normal operation, the blinking will move from filter to filter as
they are reset. This gives the user a visual confirmation that
the unit is responding to new feedback and is functioning
properly.
Q. Sometimes during the initial set-up, the first filter LED
will blink before any feedback has been introduced into
the system. Why?
A. The FBX will set a filter if the system has a hum. Check for bad
grounds. Try resetting the filters and/or the Ground switch on
the rear panel.
Q. Why does the FBX cause a noticeable hum?
A. It hums if the main power voltage drops significantly below
10% of the specified voltage. Check the A/C power mains.
Q. Why does my system sound thin and muffled?
A. Place the FBX in BYPASS MODE. If the system still sounds
thin, your problem is probably improper use of a graphic EQ.
If the problem is really the FBX, reinitialize the system.
Q. Why does my program sound clipped and distorted?
A. Make sure the FBX’s TURBO mode has turned off before your
program. Check the signal level ladder. If the red CLIP LED
lights with no other signal level LEDs lit, the FBX2020-Plus is
still in TURBO mode. TURBO mode turns off automatically
after the first dynamic filter is set, or you can turn it off manually
by pressing the LOCK FIXED button.
Q. Can I patch two FBX2020-Plus channels together for
twice the filters?
A. Yes; connect the output of the FBX2020Plus’s channel A to the
input of the 2020Plus’s channel B. Place the 2020Plus
between the output of the mixer and the input of a power amp,
and set up the channels sequentially. Bypass channel B while
setting up channel A, then lock channel A’s fixed filters (all
channel A’s filters should be fixed) by pressing channel A’s
LOCK FIXED button on the front panel after set-up.
Q. Why doesn't the FBX2020-Plus filter feedback immedi-
ately?
A. 1. Lower frequencies may take longer than higher ones.
2. Check input level of signal at the unit and reconfigure gain
so the signal level LED's on the unit light up.
3. It may be patched in an "effects loop", not directly in the
signal path.This WILL NOT WORK.
4. You may have used all 12 filters. Dynamic filters will
continue to operate by notching feedback frequencies as they
occur, but ultimately, gain will exceed filter capacity.
TROUBLESHOOTING TIPS

FBX2020P-OpGuide-031104.pmd-hto
9
FILTERS
12 independent digital notch filters per channel, controlled auto-
matically from 40 Hz to 20 KHz.
Filter width: user-controllable - either 1/10 or 1/5 octave, constant "Q"
Resolution: 1/50 octave from 100 Hz to 20 KHz
Time required to find and eliminate feedback: 0.4 seconds, typical
@ 1KHz
Total number of combined filters active per channel: user select-
able, from 1 to 12
Number of dynamic vs. fixed filters per channel: user selectable
LAST CONFIGURATION STORED IN MEMORY
INPUT/OUTPUT**
Input/Output Maximum Signal Levels: Balanced +27dBV peak,
unbalanced +21 dBV peak
Output Drive: Unit will perform as specified driving a load >600 Ohms
Input Impedance: Balanced or unbalanced >10K Ohms, PIN 2 high
Output Impedance: Balanced or unbalanced 10 Ohms nominal, PIN
2 high
Bypass: True power off bypass
Headroom: +23dB peak @ 4dBV nominal input, balanced
I/O Connectors: XLR-3 and 1/4" TRS
FBX2020-Plus ENGINEERING SPECIFICATIONS
Filter 1 Filter 12Filter 11Filter 2
ADC DAC
DSP
Feedback Detection
Center Frequency - Depth Control
Bypass Switch
1/5 or 1/10 Octave Filters
Automatic
Clip Level
Adjustment
Automatic
Clip Level
Adjustment
TRS
TRS
INPUT OUTPUT
FBX-2020Plus SIMPLIFIED INTERNAL BLOCK DIAGRAM
Analog/Digital
Converter Digital/Analog Converter
XLR
1
3
2
XLR
1
32
PERFORMANCE***
Spectral Variation: + .25 dB, 20Hz to 20 KHz
SNR: >100 dB, typical, "A" weighted
THD: <0.02% @ 22 dBV sine wave at 1 KHz
Dynamic Range: >105 dB with ClipGuard™automatic clip level
control active
POWER INPUT
Factory configured to either 115 VAC or 230 VAC. 50/60 Hz, 12 Watt
input.
FUSE REPLACEMENT
To reduce the risk of fire, replace only with 5x20 mm, .315 A, 250 V,
fast-acting fuse.
MEMORY BATTERY LIFE
7 years, typical
DIMENSIONS
1-U rack mount; 19 x 1.75 x 8.0 ins. nominal (rack mountable); 48.3 x
4.5 x 20.3 cm nominal (rack mountable)
WEIGHT
8.0 lbs. (3.6 kg) nominal
OPERATINGTEMPERATURE
Safe operating temperature: 0 - 50 degrees centigrade ambient
temperature (32 - 120F)
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
*Below approximately 200 Hz the feedback filters become slightly wider to increase the feedback and rumble capture speed at these low frequencies.
**(Note: Inputs may be balanced or unbalanced. For maximum output capability, outputs must be balanced (XLR or TRS). If either side of an output is grounded, the peak output and dynamic
range will be reduced by 6 dB.
*** Tests performed using an Audio Precision System One model 322 or equal.
*

10
LimitedWarranty
CAUTION CAUTION
This apparatus contains a lithium battery. Replacement shall be
made by qualified service personnel only. Call Sabine at (386)
418-2000 or consult an authorized Sabine agent.
FBX and FBX Feedback Exterminator®are registered trademarks of
Sabine, Inc., and are the brand names of its line of automatic feedback
controllers. Covered by U.S. Patent No. 5,245,665, Australian Patent
No. 653,736, Canadian Patent No. 2,066,624-2, German Patent No.
69118486.0, and U.K. Patent No. 0486679. Other patents pending.
Real-Q and Real-Q2 are protected by U.S. Patent No. 5,506,910.
Other patents pending.
Graphi-Q, Power-Q, Real-Q, and Real-Q2 are trademarks of Sabine, Inc.
Copyright 2003. All rights reserved.
THIS LIMITED WARRANTY VALID ONLY WHEN PURCHASED AND REGISTERED IN THE
UNITED STATES OR CANADA. ALL EXPORTED PRODUCTS ARE SUBJECT TO WAR-
RANTY AND SERVICES TO BE SPECIFIED AND PROVIDED BY THE AUTHORIZED
DISTRIBUTOR FOR EACH COUNTRY.
Cesclauses de garantie nesontvaiables qu’aux Etats-Unis etauCanada.Dans tous les autres
pays,lesclausesdegarantieet de maintenance sont fixees par le distributeur nationaletassuree
parlui selon lalegislation en vigueur.
DieseGarantieistnur in den USA and Kanadagultig.AlleExport-ProduktesindderGarantieund
demServicedesImporteursdesjewelligenLandesuntervorfen.
Esta garantia es valida solamente cuando el producto es comprado en E.U. continentales o en
Canada.Todoslosproductosqueseancompradosen el extranjero, estan sujetos a las garantias
yservicioquecada distribuidor autorizado determine y otrezca enlosdiferentespaises.
ONE-YEARLIMITED WARRANTY/REMEDY
SABINE,INC.(“SABINE”)warrants thisproducttobefreefrom defectsinmaterialandworkmanship
foraperiodofone(1)yearfromdateofpurchase PROVIDED, however, that this limited warranty is
extended only to the original retail purchaser and is subject to the conditions, exclusions and
limitationshereinaftersetforth:
CONDITIONS,EXCLUSIONS AND LIMITATIONSOFLIMITED WARRANTIES
Theselimitedwarranties shall be void and ofnoeffectif:
a.The first purchase oftheproduct is forthepurpose of resale; or
b.The original retailpurchaseis not madefroman AUTHORIZED SABINEDEALER;or
c.Theproducthas been damaged by accident or unreasonable use,neglect,improperserviceor
maintenance,orothercauses not arising out of defectsinmaterialorworkmanship;or
d.Theserialnumber affixed to the product is altered, defacedorremoved;or
e.The power supply groundingpinis removed orotherwisedefeated.In the eventofa defect in
materialand/orworkmanship coveredbythislimitedwarranty,Sabinewillrepairthe defectinmaterial
orworkmanshiporreplace theproduct,atSabine’soption;andprovided,however, that,inany case,
allcostsof shipping, if necessary, arepaidbyyou,thepurchaser.
THE WARRANTY REGISTRATION CARD SHOULD BE ACCURATELY COMPLETED,
MAILEDTO AND RECEIVED BYSABINEWITHIN FOURTEEN (14) DAYSFROMTHEDATE
OF YOUR PURCHASE.
Inordertoobtainserviceunderthesewarranties,youmust:
a.Bringthe defectiveitemtoanyAuthorized SABINEDEALERandpresenttherewith theORIGINAL
PROOFOFPURCHASE supplied to you bytheAUTHORIZEDSABINEDEALERin connection
with your purchase from him of this product. If the DEALER is unable to provide the necessary
warrantyservice,youwillbedirectedtothenearestotherSABINEAUTHORIZEDDEALERwhich
canprovidesuchservice.OR
b.Shipthedefectiveitem,prepaid, to:
SABINE,INC.
13301HIGHWAY441
ALACHUA,FL32615-8544
includingtherewithacomplete,detailed description of the problem, together with a legiblecopyof
the original PROOF OF PURCHASE and a complete return address. Upon Sabine’s receipt of
theseitems:
Ifthedefectisremedialunderthelimitedwarrantiesandtheothertermsandconditionsexpressed
havebeencompliedwith, Sabine willprovidethenecessarywarrantyserviceto repair or replacethe
productand will return it, FREIGHTCOLLECT,toyou,the purchaser.
Sabine’sliabilitytothepurchaserfordamagesfromanycause whatsoeverandregardlessoftheform
ofaction,including negligence, is limited to theactualdamagesuptothe greater of $500.00 oran
amountequaltothe purchase price of the product thatcausedthedamageorthatisthe subject of
orisdirectlyrelatedto the cause of action. Such purchase price will bethatineffectforthespecific
productwhenthecauseofaction arose. This limitation ofliabilitywillnotapplytoclaimsforpersonal
injury or damage to real property or tangible personal property allegedly caused by Sabine’s
negligence.Sabinedoesnotassumeliability for personal injury or property damage arising out
oforcaused byanon-Sabinealterationor attachment,nordoesSabineassume anyresponsibility
fordamagetointerconnected non-Sabine equipment thatmayresultfromthenormalfunctioning
andmaintenanceofthe Sabine equipment.
UNDER NO CIRCUMSTANCES WILL SABINE BE LIABLE FOR ANY LOST PROFITS,
LOST SAVINGS, ANY INCIDENTAL DAMAGES OR ANY CONSEQUENTIAL DAMAGES
ARISINGOUTOFTHEUSEORINABILITYTOUSETHEPRODUCT, EVEN IF SABINE HAS
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
THESE LIMITED WARRANTIES ARE IN LIEU OF ANY AND ALL WARRANTIES, EX-
PRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR USE; PROVIDED, HOW-
EVER, THAT IF THE OTHER TERMS AND CONDITIONS NECESSARY TO THE EXIST-
ENCE OF THE EXPRESS LIMITED WARRANTIES, AS HEREINABOVE STATED, HAVE
BEENCOMPLIED WITH, IMPLIEDWARRANTIESARE NOT DISCLAIMEDDURINGTHE
APPLICABLE ONE-YEAR PERIOD FROM DATE OF PURCHASE OF THIS PRODUCT.
SOME STATES DO NOT ALLOW LIMITATION ON HOW LONG AN IMPLIED WAR-
RANTY LASTS, OR THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSE-
QUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS OR EXCLUSIONS MAY NOT
APPLY TO YOU. THESE LIMITED WARRANTIES GIVE YOU SPECIFIC LEGAL RIGHTS,
AND YOU MAY ALSO HAVE OTHER RIGHTS WHICH MAY VARY FROM STATE TO
STATE.
THESE LIMITED WARRANTIES ARE THE ONLY EXPRESS WARRANTIES ON THIS
PRODUCT,ANDNOOTHERSTATEMENT, REPRESENTATION, WARRANTY ORAGREE-
MENT BY ANY PERSON SHALL BE VALID OR BINDING UPON SABINE.
In the event of any modification or disclaimer of express or implied warranties, or any
limitationof remedies, contained hereinconflictswith applicable law, thensuchmodification,
disclaimerorlimitation, asthecasemay be,shallbedeemed tobemodifiedtotheextentnecessary
tocomplywithsuchlaw.
Yourremediesforbreachofthesewarrantiesarelimitedtothoseremediesprovidedherein,
andSabinegives this limited warranty onlywithrespecttoequipment purchased in theUnited
StatesofAmerica.
INSTRUCTIONS-WARRANTY REGISTRATION CARD
1.Mail the completed WARRANTYREGISTRATIONCARD to:
SABINE,INC.
13301HIGHWAY441
ALACHUA,FL32615-8544
a. Keep the PROOF OF PURCHASE. In the event warranty service is required during the
warrantyperiod,you willneedthisdocument.Therewill benoidentificationcardissued bySabine,
Inc.
2. IMPORTANCE OF WARRANTY REGISTRATION CARDS AND NOTIFICATION OF
CHANGES OF ADDRESS:
a. Completion and mailing of WARRANTY REGISTRATION CARDS - Should notification
becomenecessaryforany conditionthatmayrequirecorrection,theREGISTRATION CARDwill
helpensurethatyouarecontactedandproperlynotified.
b. Notice of address changes - If you move from the address shown on the WARRANTY
REGISTRATIONCARD,youshould notifySabineofthechangeof addresssoastofacilitateyour
receiptofanybulletinsorotherformsofnotificationwhich may become necessary in connection
withanyconditionthatmayrequiredisseminationofinformation or correction.
3.YoumaycontactSabinedirectlybytelephoning(386) 418-2000.
4.PleasehavetheSabineproductname and serial number available when communicating
withSabineCustomerService.
EXPOSURE TO EXTREMELY HIGH NOISE LEVELS MAY CAUSEAPERMANENT HEAR-
ING LOSS. INDIVIDUALS VARY CONSIDERABLY IN SUSCEPTIBILITYTO NOISE INDUCED
HEARING LOSS, BUT NEARLY EVERYONE WILLLOSE SOME HEARING IF EXPOSED TO
SUFFICIENTLYINTENSE NOISE FOR ASUFFICIENT TIME. THE U.S. GOVERNMENT’S
OCCUPATIONAL SAFETYAND HEALTHADMINISTRATION (OSHA) HAS SPECIFIED THE
FOLLOWING PERMISSIBLE NOISE LEVEL EXPOSURES:
DURATION/DAY IN HOURS SOUND LEVEL IN dBA, SLOW RESPONSE
8 90
6 92
4 95
3 97
2 100
1-1/2 102
1 105
1/2 110
1/4 or less 115
ACCORDING TO OSHA, ANY EXPOSURE IN EXCESS OF THE ABOVE PERMISSIBLE
LIMITS COULD RESULT IN HEARING LOSS. EAR PLUGS OR PROTECTORS IN THE EAR
CANALS OR OVER THE EARS MUST BE WORN WHEN OPERATING THIS DEVICE IN
ORDER TO PREVENT A PERMANENT HEARING LOSS, IF EXPOSURE IS IN EXCESS OF
THE LIMITS AS SET FORTHABOVE. TO ENSURE AGAINST POTENTIALLY DANGEROUS
EXPOSURE TO HIGH SOUND PRESSURE LEVELS, IT IS RECOMMENDED THAT ALL
PERSONS EXPOSED TO EQUIPMENTCAPABLE OF PRODUCING HIGH SOUND PRES-
SURE LEVELS SUCH AS THIS DEVICE BE PROTECTED BY HEARING PROTECTORS
WHILE THIS UNIT IS IN OPERATION.
Cautions & Warranty

FBX2020P-OpGuide-031104.pmd-hto
11
Warning! This equipment must be earthed.
Caution! Risk of electric shock. Do not open.
Caution! Shock hazard. Do not remove covers. No user serviceable
parts inside. Refer servicing to qualified service personnel.
Warning! To reduce the risk of fire or electric shock, do not expose this
product to rain or moisture.
Attention! Cet appareil doit être reliéàla terre.
Attention! Risque de choc électrique; ne pas ouvrir.
Attention! Risque de choc; ne pas oter les capots. Aucune pièce
accessible àl'intérieur. S'addresser àun technicien qualifié.
Attention! Pour réduire le risque d'incendie ou de choc électrique, ne
pas laisser l'appareil sous la plouie ou àl'humidité.
Achtung! Dieses Gerät muss schutzgeerdet sein.
Achtung! Gefar eines elektrischen Stormschlags. Gehause nicht
öffnen.
Achtung! Gefar eines elektrischen Stormschlags. Gehäuse nicht
öffnen. Keine con Benutzer zu bedienenden Teile im Geräteinneren.
Überlassen Sie das Gerät zu Servicezwecken nur geschultem
Fachpersonal.
Um Brandgefar oder das Risiko eines elektrischen Schlags
auszuschließen, das Gerät vor Nässe und Feuchtigkeit schützen.
Advertencia! Este equipo debe estar conectado a tierra.
Precaución! Reisgo de descarga eléctrica. No abrir.
Precaución! Riesgo de descarga eléctrica. No desmontar las tapas.
Piezas interiores no reparables por el usuario. Reparable sólo por
personal cualificado.
Advertencia! Para reducir el riesgo de incendio o de descarga eléctrica
no exponga este producto a la lluvia o humedad.
FCC Statement:
This device complies with Part 15 of the FCC Rules. Operation is subject
to the following conditions: (1) This device may not cause harmful inter-
ference; and (2) This device must accept any interference received,
including interference that may cause undesired operation.
Warning:
Changes or modifications to this unit not expressly approved by the party
responsible for compliance could void the user's authority to operate the
equipment.
NOTE: This equipment has been tested and found to comply with the limits
for a Class B digital device, pursuant to Part 15 of the FCC Rules. These
limits are designed to provide reasonable protection against harmful inter-
ference in a residential installation. This equipment generates, uses, and
can radiate radio frequency energy and, if not installed and used 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 deter-
mined by turning the equipment off 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 different
from that to which the receiver is connected.
•Consult the dealer or an experienced radio TV technician for
help.
Canadian Compliance Statement
This digital apparatus does not exceed the Class B limits for radio noise
emissions from digital apparatus set out in the Radio Interference Regula-
tions of the Canadian Department of Communications.
Le present appareil numerique n'emet pas de bruits radioelectriques
depassant les limites applicables aux appareils numeriques de la class B
prescrites dans le Reglement sur le brouillage radioelectrique edicte par le
ministere des Communications du Canada.
Japanese EMI Compliance Statement
The FBX2020-Plus is designed to operate from standard AC
power. Please be sure the power in your area is compatible with
the power requirements marked on the rear of the unit. Using the
wrong input voltage may cause permanent damage to the unit and
will void the warranty.
The FBX2020-Plus is supplied with one of the following AC power
cords:
Japan 100 VAC
U.S./North America 120 VAC
Continental Europe 230 VAC
UnitedKingdom 240 VAC
Australia 240 VAC
Warning!
1. Read all safety and operating instructions before using this
product.
2. All safety and operating instructions should be retained for
future reference.
3. Obey all cautions in the operating instructions and on the unit.
4. All operating instructions should be followed.
5. Use only shielded audio and data cables.
6. This product should not be used in the presence of moisture or
rain, or near any water, i.e., a bathtub, sink, swimming pool, wet
basement, etc.
7. This product should be located so that its position does not
interfere with proper ventilation. Do not use in direct sunlight. Do
not place flat against a wall or in a built-in enclosure that will
impede the flow of cooling air.
8. This product should not be placed near a source of heat such
as a stove or radiator.
9. Connect only to a power supply of the type marked on the unit
adjacent to the power entry module.
10. Never break off the ground pin on the power supply cord.
11. Power supply cords should always be handled carefully. Never
walk or place equipment on power supply cords. Periodically check
cords for cuts or signs of stress, especially at the plug and the point
where the cord exits the unit.
12. The power supply cord should be unplugged when the unit is to
be unused for long periods of time.
13. Care should be taken so that objects do not fall and liquids are
not spilled into the unit through the ventilation holes or any other
openings.
14. This unit should be checked by a qualified service technician if:
A. The power supply cord or plug has been damaged.
B. Anything has fallen or been spilled into the unit.
C. The unit does not operate correctly.
D. The unit has been dropped or the enclosure damaged.
15. The user should not attempt to service this equipment. All
service work should be done by a qualified service technician.
OSHA 2201; 1995 revised.
Caution!
Replace the fuse with a fuse of exactly the same rating
specified on the rear of the product.

12
MADE IN USAMADE IN USA
MADE IN USAMADE IN USA
MADE IN USA
Manufactured by: Sabine, Inc.
13301 NW US Highway 441
Alachua, Florida 32615-8544 USA
Phone: [phone] •Fax: [phone]
www.Sabine.com
Register your FBX2020-Plus online at Sabine.com