SABINE FBX-2020 User manual

©1995-2001 Sabine, Inc.
CONGRATULATIONS! You nowhavethestate-of-the-artinfeedback control. Your SabineFBX-2020 Feedback Exterminator®—a single channel,
20-bit digital filtering device— gives you automatic real-time feedback control and increases the clarity and volume of your system.
The FBX-2020 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 10 Constant Q micro-filters on the resonating frequency and eliminates the feedback in typically less than one second.
Special features of the FBX-2020:
• An improved algorithm that allows the FBX-2020 to better distinguish the difference between feedback and music
• Improved 20-bit digital resolution, providing superior dynamic range and signal-to-noise ratio
•10 feedback filters, giving the unit more feedback elimination power for the toughest venues.
•ClipGuard™adaptivecliplevelcontrol,withTURBOsetupmode,increasestheeffectivedynamicrangebymorethan10dB
and makes setup faster and easier.
• StandardFBXfeaturessuchaslockablefixedfiltersandswitchable1/10-and1/5-octaveConstantQfiltersarealsoincluded
and now have convenient front panel switches.
QUICK-START OPERATION
For best results, read all operating instructions before using the FBX-2020. 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 master volume down, put the FBX-2020 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. (Factory default is nine fixed and three dynamic filters.) The rest of
the filters continually catch and update new feedback frequencies throughout the program.
You're ready to go.
READ THE ENTIRE OPERATING GUIDE FOR COMPLETE INSTRUCTIONS.
V2
OPERATING GUIDE
QUICK-STARTOPERATION 1
DECLARATION OF CONFORMITY 2
APPLICATIONOF COUNCILDIRECTIVE 2
ABOUT THE FBX-2020 3
FREQUENCY RESPONSE 3
WORLD'SBEST FEEDBACK CONTROLLER 3
WHO NEEDS FBX? 3
WHY THE FBX? 3
DIRECT HIT ON FEEDBACK!3
ACTIVE/BYPASS SWITCH 4
SIGNAL LEVEL 4
RESET 4
SET TOTAL NUMBER OF FILTERS 4
SET FIXED 4
LOCK FIXED FILTERS 4
A/CPOWER INPUT 4
AUDIO INPUTS & OUTPUTS 4
FBX-2020 CONTROLS 4
FIFTH OCTAVE 4
FILTER STAGE ACTIVITY 4
POWER SWITCH 4
FUSE 4
APPLICATION DIAGRAMS 5
FBXSETUP FOR MONITORS 5
FBXSETUP FOR ENTIRE MIX 5
FBXSETUP FOR SINGLE INSERT POINT 6
FBXSETUP FOR INSERT SEND & RETURN 6
FBX-2020 6
OPERATING 6
INSTRUCTIONS 6
WHERE THE FBXFITS IN YOUR SOUND SYSTEM 6
ANOTE ABOUT GRAPHIC EQUALIZERS 6
UNDERSTANDING FIXED&DYNAMICFILTERS 6
CLIPGUARD™ADAPTIVE CLIP LEVEL CONTROL 6
CLIPGUARDTMTURBO MODE GUIDE 6
HOW TOOPERATE THE FBX-2020 7
HOW TOUSE THE FBX-2020 FEATURES 8
USING THE LOCK FIXED FEATURE 8
SELECTING FILTER WIDTH 8
IMPORTANT OPERATING CONSIDERATIONS 8
MEMORY 8
BYPASS MODE 8
RESETTING THE FILTERS 8
TURBOMODE SETUP 8
DEFEATING TURBO MODE 8
MOBILE VS.STATIONARY MICROPHONES 8
FREQUENTLYASKEDQUESTIONS 9
INDEX 9
FBX-2020ENGINEERINGSPECIFICATIONS 10
CAUTIONS & WARNINGS 11
LIMITED WARRANTY 12

2
DECLARATION OF CONFORMITY
Application of Council Directive: 73/23/EEC and 89/336/EEC
Standard to which conformity is declared:
EN60065:1993
EN50082-1:1992
EN55022 ClassB
Manufacturer’s Name: Sabine,Inc.
Manufacturer’sAddress: 13301 Highway441
Alachua,FL32615-8544 USA
Type of Equipment: Equalizer
Model No.: FBX-2020
Serial No.:
Year of Manufacture: 1997and on
I,theundersigned,herbydeclarethattheequipmentspecifiedabove conformstotheaboveDirectiveandStandard.
Place: Alachua,Florida,USA Signature:
Date: October4,2000 Full Name: DoranOster,SabinePresident

3
ABOUT THE FBX-2020
3
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
atwo-octave range. And,asthisillustrationshows,you can'tplace
a graphic EQ filter precisely on the ringing frequency. When you
pull down multiple sliders in a normal setup (below), you end up
withgiantholesinyourmusic. Ontheotherhand,FBXmicro-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.
Frequency Response
FullSet-UpFBXVs.1/3OctaveGraphicEqual-
izer. Test procedure: A PA system was set up
usingamicrophone,mixer,FBX,powerampand
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
achievedwiththeFBX. The frequency response
curves of each device were then plotted.
World's Best Feedback Controller
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 the FBX functions automatically, even during the program. Another is
theFBX micro-filtersare precisely placedwhile EQ filtersare fixed. Thedifference: FBX filtersdo nothave to beas deep,so there
is more system gain. The 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 FBX-2020,
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 FBX?
Virtually every sound system will be improved with the FBX. Small bands that do not have sound technicians can now increase
theirmonitor volumes so theycanhearthemselvesclearlyandwithfull fidelity, without worryingiftheprogramisgoingtoberuined
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 FBX-2020 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.
FREQUENCYRESPONSE: FBX1/10-OctaveFilterVs.
1/3-OctaveGraphicEQFilter(12dBdepth;LogScale).
FBX filter
Feedback
Frequency

4
FBX-2020 CONTROLS
A/C Power Input
TheFBX-2020isfactoryconfiguredtooperateateither115VAC
or 230 VAC. Using the wrong input voltage may cause perma-
nent damage to the unit and will void the warranty.
Audio Inputs & Outputs
1/4" TRS and XLR balanced and unbalanced.
Active/Bypass Switch
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.
Signal Level
The LED ladder indicates the signal strength relative to the
FBX's input clip level. The red CLIP LED indicates clipping; it
also indicates the unit is in TURBO mode.
Reset
To reset ALL filters, hold the reset button for 4 seconds until all
filter LEDs are off.
Set Total Number of Filters
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.
Set Fixed
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. (Factory default is
nine fixed and three dynamic filters.)
Lock Fixed Filters
When the LOCK FIXED button is pressed, its LED will light to
indicate that the FBX is in LOCK FIXED mode. LOCK FIXED
mode can be activated at any time after system setup and will
stay on until the button is pressed again and the LED turns off.
EngagingtheLOCKFIXED button also takes theFBX-2020 out
of ClipGuard's TURBO setup mode.
Fifth Octave
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.
Filter Stage Activity
When one of the unit’s 10 filters is activated, the corresponding
LED lights. A blinking LED indicates the filter that was most
recently activated.
Power Switch
The ON/OFF switch is a two-position push button switch. The
power indicator LED will light when the FBX is operational.
FBX-2020 Front Panel
FBX-2020 Back Panel
Fuse
This equipment is fitted with an IEC power inlet incorporating
a built-in fuse holder. To change the fuse in this socket:
1.Disconnect the power cord from the unit.
2.Pull out the fuse holder and remove the old fuse.
3.Install the new fuse into the holder. Replace only with
5x20mm, 0.315A, 250V F (fast acting) fuse.
4.Refit the fuse cover.

5
APPLICATION DIAGRAMS
FBX Setup for Entire Mix
FBX OUT
Main OUT
FBX IN
Amp IN
Amplifier
All other Signal
Processing
Equipment
FBX Setup for Monitors
Monitor OUT
FBX IN
FBX Out
Amp In
Amplifier

6
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
apower amp. In thisposition,the FBX cansenseand eliminate
feedback occurring in any channel of the mixer. The FBX can
also be used on a mixer insert point.
A note about graphic equalizers
GraphicEQsareexcellentforshapingsound,andtheyarefairly
simple to use. However, using one-octave-wide EQ filters to
control feedback invariably causes an unnecessary decrease
in the gain and fidelity of the program. It's easy to see that if
feedback occurs somewhere between the sliders, you will
have to pull one of those EQ sliders down pretty far to eliminate
feedback. That pulls out plenty of your program, too. On the
other hand, you'll get considerably more net gain and much
better sound quality if you use wide graphic EQ filters for tone
control and insist on narrow filters for feedback control.
Ifyou use an equalizer,placetheFBXaftertheEQin the signal path.
Use the EQ’s controls to shape the tonal response of the sound
system, but DO NOT NOTCH FOR FEEDBACK.
Understanding FIXED & DYNAMIC filters
Beforeoperating theFBX,youneedtounderstandthetwo
typesofFBXfilters:FIXEDandDYNAMIC.FIXEDFILTERS
retain their frequency center-points until the unit is reset by
the user. The system’s gain before feedback is limited primarily by
!
Read
This
!
Read
This
the number of fixed fil-
ters;i.e.,increasingthe
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
arecontinually reset automatically todiffer-
ent frequencies as new feedback occurs during the program. For
most applications, the optimal setting is nine FIXED and three
DYNAMICFILTERS. Thisis the factorydefault.
ClipGuard™ Adaptive Clip Level Control
Your FBX-2020 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 FBX-2020 internal dynamic range to the constantly changing
programlevel and maintainsunity gain. ClipGuard™extendsthe
effectivedynamic range ofyourFBX-2020 from 100dBto105dB!
ClipGuard™ incorporates TURBO mode setup, another new
feature. It cuts the time for FBX filter initialization to just a few
FBX-2020
OPERATING
INSTRUCTIONS
FBX Setup for Single Insert Point
Note: If you're using a mixer with unbalanced
1/4" outputs, you must use standard unbal-
anced cables and connectors when connect-
ingittotheFBX. Similarly,ifyourmixeriswired
for balanced 1/4" (Ring/Tip/Sleeve) outputs,
you must use that type of 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(+21dBVmax.signallevelunbal.;+27dBV
max. signal level bal.).
FBX Setup for Insert Send & Return
FBX-2020 OUTPUT & INPUT
High Z
Insert
Send
Low Z
Insert
Return
Mixer
Input
Channel
B
Mixer
Input
Channel
A
High Z
Insert
Send
Low Z
Insert
Return
Mixer Input
Channel B
High Z
Insert
Low Z
Mixer
Input
Channel
A
Mixer
Input
Channel
B
High Z
Insert
Low Z
FBX-2020 OUTPUT & INPUT
Use 1/4" TRS plug for balanced sends/inserts
Use 1/4" TS plug for unbalanced sends/inserts 1/4" TRS plug
1/4" TRS plug

7
!
Read
This
IMPORTANT TIP
You can mix 1/10- and 1/5-octave filters in the same channel. If
you have an especially bad feedback problem, try making the first
few filters 1/5-octave and the remaining filters 1/10-octave.
TURBOmodespeedsuptheFBXfilterinitial-
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
manuallybypressingtheLOCKFIXEDbutton.
(Press it again to unlock the filters.)
NO!TURBOmodeshouldbeturnedoffeither
automatically or manually before your pro-
gram begins. If left on, the 2020 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 2020
work during the
program with
TURBO on?
How do I turn off
TURBO?
How do I know
TURBO is on?
ClipGuardTM TURBO Mode Guide
NOTE: IfyoupressLOCKFIXEDtoturnoffTURBOmode
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 dy-
namic filter sets, you will not be able to use the rest of the
fixed filters unless you reset and reinitialize the unit.
WARNING: Follow the setup procedure outlined on the
left, and do not play audio program during TURBO setup
mode.Otherwise,theFBX-2020willclipandmaysetFBX
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. Press LOCK FIXED again
ifyouwantFIXEDfilterstoremainactive.)You'llknowthe
2020 is in TURBO mode if the red CLIP LED flashes
when no other signal level LEDs are on. (See "How do
IturnoffTurbo?"intheClipGuardTURBOModeGuide
above.)
NOTE: Anyloud soundspicked up byopen microphones
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 offTURBO by pressingLOCK FIXED on,then
off before you initialize for feedback. Remember: if you
leaveLOCKFIXEDon,thefixedfilterswon’tinitialize.The
LED indicating LOCK FIXED should be off when initial-
izing.
seconds, and it greatly reduces the volume level of the feedback
duringsetup.TheFBX-2020issetinTURBOmodeatthefactory
andautomaticallyengageseverytimeyoupressRESETorSET
TOTAL NO (to reset filters or set total number of filters). The
FBX-2020 automatically returns to normal program mode
whenthefirstdynamicfilterissetorwhenyoupressthefront
panelLOCKFIXEDbutton. ALLFILTERLEDSWILLCYCLETO
INDICATETHEFBXISABOUTTOEXITTURBOMODE.
How To Operate The FBX-2020
Follow these steps to obtain the maximum gain before feed-
back without changing the tonal quality of your program.
1.Place the speakers and microphones in the positions
where they will be used during the program. Avoid placing
microphones directly in front of speakers.
2. If you possess any equipment in the signal path with a noise
gate,youMUST DISENGAGE these noisegatespriorto the
setup procedure. You may reengage these noise gates
uponconclusion of your FBX setup. (Itisalsorecommended
to disengage compressors in the signal path)
3.Set the master volumes to their lowest positions. Turn on
the mixer, then the FBX (make sure the FBX is in BYPASS
mode, with the red BYPASS LED on), then any other
accessories and finally the power amp. If you are using a
graphic EQ, adjust only for the desired tonal qualities, but
DONOTNOTCHFORFEEDBACK.Adjustthebalancefor
each mixer channel, and set the sound system’s master
volume to minimum.
4.Press RESET until all LEDs stop flashing.
5.You may set the total number of filters you want to activate
(factorydefaultis10filters-skipto#6ifdefaultisOKforyour
application)byholdingdowntheSETTOTALNO.buttonfor
4 seconds. The LEDs will blink 4 times and then go out.
Release the SET TOTAL NO. button. The LEDs will begin
to light in sequence. 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.Nowsetthenumberoffixedfiltersyouneed(factorydefault
is7 fixedand 3dynamic - skip to #7if defaultis OK for your
application). DepresstheSETFIXEDbuttonfor4seconds.
The total number of enabled filters set in step 5 will blink
4 times and go out. Release the SET FIXED button, and
the LEDs will begin to light in sequence. When the LED
corresponding to the desired number of fixed filters lights,
press the SET FIXED button. You've successfully set the
number of fixed filters.
7.PressBYPASStoputtheFBXinactivemode(redLEDoff).
8.Slowly raise the sound system’s master volume until
feedback occurs. The FBX will quickly remove the feed-
back.The first FILTER LEDwillthenblinktoindicateafilter
has been set. Repeat this procedure until all of the FIXED
FILTERSand one oftheDYNAMIC FILTERS areset.(The
Clip Level mode LED will go off.)
9.Now lower the master volume slightly so that the system
is not on the verge of another feedback point. This is the
maximumvolumelevelthattheFBXwillbe able to provide.
Higher levels will cause uncontrollable feedback.
10. You're ready to go. ClipGuard™ will automatically match
the input level to the best internal dynamic range.

8
How To Use The FBX-2020 Features
UsingtheLOCKFIXED feature
In very few 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
after setup. The LOCK FIXED LED will light to indicate that the
FBX is in LOCK FIXED mode. The fixed filters stay locked until
you press the LOCK FIXED button again.
Selecting filter width
If you're using the FBX for a music application, the standard 1/
10-octave Constant Q filter is usually preferable. However, in
spoken word applications, such as lectures or teleconferenc-
ing, 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. You can mix filter widths in the
same channel (see "IMPORTANT TIP" below).
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
TheFBX has atruepower-off bypass. Thesignal is unaffected
in BYPASS MODE even if the unit is turned off. Please note
thatifacombination ofBALANCED andUNBALANCED
inputs and outputs is used, the signal may be discon-
nectedin BYPASS MODE.
Resettingthefilters
The user must reset the FBX if the microphones or speakers
aremovedsignificantly.Toresettheunit,placethePAsystem’s
master volume to minimum and then press the RESET button
untilthe LEDs flashabout4seconds — andthe FILTERLEDs
stop flashing. Then follow the system initialization procedure
explained previously.
TURBOModeSetup
The FBX-2020 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 2020 is set in TURBO mode at the
factory and automatically engages every time you
press RESET (resetting filters). The 2020 automati-
cally returns to normal program mode when the first
dynamic filter is set or when you press the front panel
LOCKFIXEDbutton. ALLFILTERLEDSWILLCYCLETO
INDICATETHEFBXISABOUTTOEXITTURBOMODE.
WARNING: TURBO Mode will cause distortion inyour
audio program — it is for setup only. Youmustfollowthe
setup procedure outlined in the previous section, and do not
play program during TURBO setup mode. Otherwise the 2020
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 2020
isin TURBO mode if the red CLIP LED flashes when no
other signal level LEDs are lit.
Defeating Turbo Mode
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).
Mobilevs. StationaryMicrophones
Onesignificant advantageoffered by theSabine family ofFBX
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 wire-
less microphones, when the user of the wireless mic is
movingaround thestage/auditorium. As a microphonemoves
in a sound space, with varying degrees of proximity to the
speakers and varying acoustic responses, feedback frequen-
cies 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.

9
FREQUENTLY ASKED QUESTIONS
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 if possible. 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. ThesignalinputLEDsdonotlight.Theunitwillnotcatch
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
disconnected from the back of the unit.
Q. CanImixbalancedandunbalancedinputsandoutputs?
A. Yes. An unbalanced input and balanced output are com-
patible. However,abalancedinputandunbalancedoutput
mayresult in a6 dBloss of dynamicrange, and thebypass
function may not operate correctly.
Q. WhydoesoneoftheFILTERACTIVITYLEDsblink?
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
thatthe unit isresponding to newfeedbackand is function-
ing properly.
Q. Sometimesduringtheinitialsetup,thefirstfilterLEDwill
blinkbeforeanyfeedbackhasbeenintroducedintothe
system. Why?
A. The FBX will set a filter if the system has a hum. Check for
bad grounds. Try resetting the filters.
Q. Why does the FBX cause a noticeable hum?
A. Ithums if themain power voltagedropssignificantly below
10% of the specified voltage. Check the A/C power mains.
Q. Why does my system sound thin and muffled?
A. PlacetheFBXinBYPASSMODE.Ifthesystemstillsounds
thin, your problem is probably with improper use of a
graphicEQ. Ifthe problem isreallythe FBX, reinitializethe
system.
Q. Why does my program sound clipped and distorted?
A. Make sure the FBX's TURBO mode has turned off before
your program begins. Check the signal level ladder. If the
red CLIP LED flashes when no other signal level LEDs are
on, the FBX-2020 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. Why won't the rest of the fixed filters set after I press
LOCKFIXEDtoturnoffTURBOmode?
A. If you press LOCK FIXED to turn off TURBO mode before
all the fixed filters are set, and you want to use the rest of
thefixedfilters,pressLOCKFIXEDagain
before adynamic
filter sets. Once a dynamic filter sets, you will not be able
to use the rest of the fixed filters unless you reset the unit
and start initialization again.
INDEX
Symbols
1/10 Octave Filter 3, 4, 7, 8
1/3 Octave Filter 3
1/5 Octave Filter 1, 4, 7, 8
A
Adaptive Clip Level 6
B
Balanced/Unbalanced IN/OUT 4, 6, 8
Bypass 4, 7, 8
C
ClipGuard 4, 6, 7
D
Dynamic Filter 4, 7
F
Filter LEDs 7, 8
Fixed Filter 4, 6, 7
Fuse 4, 10, 11
L
Lock Fixed 4, 7, 8
M
Master Volume 7, 8
Microphone 3, 7, 8
Monitor 3, 5
Music Application (for FBX) 8
P
Pipe Organs & FBX 8
R
Reset 6, 7, 8
S
Send & Return 6
Set Fixed 4, 7
Set Total Number of Filters 7
Software Installation 11
Spoken Word Application (for FBX) 8
T
Turbo Mode 4, 6, 7, 8
V
Voltage 4, 11
W
Wireless Microphones 8

10
FBX-2020 ENGINEERING SPECIFICATIONS
(SPECIFICATIONSSUBJECTTOCHANGEWITHOUTNOTICE)
FILTERS
10 independent digital notch filters, controlled automatically from 40
Hz to 20 KHz.
Filter width: user-controllable, either 1/10 or 1/5 oct., Constant Q 1
Resolution: 1/50th Octave
Time required to find and eliminate feedback: 0.4 seconds,
typical @ 1KHz
Total number of combined filters active: user selectable, from
1-10
Number of dynamic vs. fixed filters: user selectable
LASTCONFIGURATIONSTOREDINMEMORY
INPUT/OUTPUT2
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
PERFORMANCE
3
Spectral Variation: < .25 dB, 20Hz to 20 KHz
SNR: >100 dB, typical, "A" weighted
NOTES
1Below approximately 200 Hz the feedback filters become slightly
wider to increase the feedback and rumble capture speed at these
low frequencies.
2Note: 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.
3Tests performed using an Audio Precision System One model 322
or equal.
THD: <0.02% @ 23 dBV sine wave at 1 KHz
Dynamic Range: >110 dB with ClipGuard™ automatic clip level
control active
POWERINPUT
Factory configured to either 115 VAC or 230 VAC. 50/60 Hz, 12
Watt input.
FUSEREPLACEMENT
To reduce the risk of fire, replace only with 5x20 mm, .315 A, 250 V,
fast-acting fuse.
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
7.0 lbs. (3.3 kg) nominal
OPTIONS
Input/output transformer option
All FBX Feedback Exterminators conform to all Year 2000 (Y2K)
standards.
(Shows one channel only)
FBX-2020SIMPLIFIED INTERNAL BLOCKDIAGRAM

11
Warning!Thisequipmentmustbeearthed.
Caution!Riskofelectricshock.Donotopen.
Caution!Shockhazard.Donotremovecovers.Nouserserviceableparts
inside.Referservicingtoqualifiedservicepersonnel.
Warning! To reduce the risk of fire or electric shock, do not expose this
producttorainormoisture.
Attention!Cetappareildoitêtrereliéàlaterre.
Attention!Risquedechocélectrique;nepasouvrir.
Attention!Risquedechoc;nepasoterlescapots.Aucunepièceaccessible
àl'intérieur.S'addresseràuntechnicienqualifié.
Attention!Pourréduirelerisqued'incendieoudechocélectrique,nepas
laisserl'appareilsouslaplouieouàl'humidité.
Achtung!DiesesGerätmussschutzgeerdetsein.
Achtung!GefareineselektrischenStormschlags.Gehausenichtöffnen.
Achtung!Gefar eines elektrischenStormschlags.Gehäuse nichtöffnen.
KeineconBenutzerzubedienendenTeileimGeräteinneren.
ÜberlassenSiedasGerätzuServicezweckennurgeschultemFachpersonal.
UmBrandgefaroderdasRisikoeineselektrischenSchlagsauszuschließen,
dasGerätvorNässeundFeuchtigkeitschützen.
Advertencia!Esteequipodebeestarconectadoatierra.
Precaución!Reisgodedescargaeléctrica.Noabrir.
Precaución!Riesgodedescargaeléctrica.Nodesmontarlastapas.Piezas
interioresnoreparablesporelusuario.Reparablesóloporpersonalcualificado.
Advertencia!Parareducirelriesgodeincendioodedescargaeléctricano
expongaesteproductoalalluviaohumedad.
FCC Statement:
ThisdevicecomplieswithPart15,ClassB,oftheFCCRules. Operationis
subjecttothefollowingconditions:(1)Thisdevicemaynotcauseharmful
interference;and (2) This device mustacceptanyinterference received,
including interference that may cause undesired operation.
Warning:
Changesormodificationstothisunitnotexpresslyapprovedbytheparty
responsibleforcompliancecouldvoidtheuser's authority to operate the
equipment.
NOTE:Thisequipmenthasbeentestedandfoundtocomplywiththelimits
foraClassBdigitaldevice,pursuanttoPart15oftheFCCRules. Theselimits
aredesignedtoprovidereasonableprotectionagainstharmfulinterference
inaresidentialinstallation. Thisequipmentgenerates,uses,andcanradiate
radiofrequencyenergyand,ifnotinstalledandusedinaccordancewiththe
instructions,maycauseharmfulinterferencetoradiocommunications. How-
ever, there is no guarantee that interference will not occur in a particular
installation. Ifthisequipmentdoescauseharmfulinterferencetoradioor
televisionreception,whichcanbedeterminedbyturningtheequipmentoff
andon,theuserisencouragedtotrytocorrecttheinterferencebyoneor
moreofthefollowingmeasures:
• 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
emissionsfromdigitalapparatussetoutintheRadioInterferenceRegula-
tionsoftheCanadianDepartmentofCommunications.
Le present appareil numerique n'emet pas de bruits radioelectriques
depassantleslimitesapplicablesauxappareilsnumeriquesdelaclassB
prescritesdansleReglementsurlebrouillageradioelectriqueedicteparle
ministeredesCommunicationsduCanada.
CAUTIONS & WARNINGS
1. Read all safetyandoperating instructionsbeforeusing thisproduct.
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 productshould not be used in the presenceof moistureor 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
notplace flat against a wall or ina built-in enclosure that willimpede
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
walkorplaceequipmentonpowersupplycords. Periodicallycheck
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.
The FBX-2020PissuppliedwithoneofthefollowingACpowercords:
Japan 100VAC
U.S./NorthAmerica 120VAC
ContinentalEurope 230VAC
UnitedKingdom 240VAC
Australia 240VAC
Caution!
Replacethefusewithafuseofexactlythesameratingspecifiedonthe
rearoftheproduct.
TheunitisdesignedtooperatefromstandardACpower. Pleasebe
surethepowerinyourareaiscompatiblewiththepowerrequirements
markedontherearoftheunit.Usingthewronginputvoltagemaycause
permanentdamagetotheunitandwillvoidthewarranty.
Warning!
Japanese EMI Compliance Statement

12
Sabine, Inc.
13301 Highway 441
Alachua, Florida 32615-8544
Phone: [phone]
Fax: [phone]
©2000 Sabine, Inc.
LIMITED WARRANTY
CAUTION FBXand FBX Feedback Exterminatorareregisteredtrademarks
of Sabine, Inc., and are the brand names of its line of automatic
feedback controllers. Covered by U.S. Patent No. 5,245,665,
AustralianPatentNo.653,736,CanadianPatentNo.2,066,624-2,
GermanPatent No. 69118486.0, and U.K. Patent No. 0486679.
Otherpatents pending.
REAL-QandREAL-Q2areprotectedbyU.S.PatentNo.5,506,910.
Otherpatents pending.
Graphi-Q,POWER-Q, REAL-Q,andREAL-Q2 aretrademarksof
Sabine,Inc.
Copyright 2001. All rights reserved.
THIS LIMITED WARRANTYVALIDONLYWHEN PURCHASED AND REGISTERED IN THE
UNITED STATES OR CANADA. ALL EXPORTED PRODUCTS ARE SUBJECT TO WAR-
RANTYANDSERVICES TO BE SPECIFIED AND PROVIDED BY THEAUTHORIZED DIS-
TRIBUTOR FOR EACH COUNTRY.
Cesclausesdegarantienesontvaiablesqu’auxEtats-UnisetauCanada.Danstouslesautrespays,
lesclauses degarantie etdemaintenancesontfixees parledistributeurnationalet assureepar lui
selonla legislation envigueur.
DieseGarantieistnurindenUSAandKanadagultig.AlleExport-ProduktesindderGarantieunddem
ServicedesImporteursdesjewelligenLandesuntervorfen.
Estagarantiaes valida solamente cuando el productoescompradoenE.U. continentales o en
Canada.Todoslosproductosqueseancompradosenelextranjero,estansujetos alas garantiasy
servicioque cadadistribuidorautorizadodeterminey otrezcaenlos diferentespaises.
ONE-YEAR LIMITED WARRANTY/REMEDY
SABINE,INC.(“SABINE”)warrantsthisproduct tobefreefromdefectsinmaterialandworkmanship
foraperiodofone(1)yearfromdateofpurchasePROVIDED,however, thatthis limitedwarranty is
extendedonlytotheoriginalretail purchaserandissubjecttotheconditions,exclusionsandlimita-
tionshereinafter setforth:
CONDITIONS, EXCLUSIONS AND LIMITATIONS OF LIMITED WARRANTIES
Theselimited warrantiesshallbevoidand ofnoeffect if:
a.The firstpurchaseof theproductis for thepurposeof resale;or
b.The original retailpurchaseis not made fromanAUTHORIZED SABINE DEALER;or
c.The producthasbeen damagedbyaccident orunreasonableuse, neglect,improperservice or
maintenance,or othercauses notarisingout ofdefectsinmaterialor workmanship;or
d.Theserialnumber affixedto theproduct isaltered,defacedorremoved;or
e.Thepowersupplygroundingpinisremovedorotherwisedefeated.Intheeventofadefect inmaterial
and/orworkmanshipcovered by this limited warranty, Sabine will repairthe defect inmaterialor
workmanshiporreplacetheproduct,atSabine’soption;andprovided,however, that,inanycase,all
costsofshipping,ifnecessary, arepaidby you,thepurchaser.
THE WARRANTY REGISTRATION CARD (or ONLINE REGISTRATION FORM) SHOULD
BE ACCURATELY COMPLETED, MAILED TOANDRECEIVED BY SABINEWITHIN FOUR-
TEEN (14) DAYS FROM THE DATE OF YOUR PURCHASE .
Inordertoobtainserviceunder thesewarranties, youmust:
a.BringthedefectiveitemtoanyAuthorizedSABINEDEALERandpresenttherewiththeORIGINAL
PROOFOF PURCHASEsuppliedto you bytheAUTHORIZED SABINEDEALERin connection
withyourpurchasefromhimofthisproduct. IftheDEALERisunabletoprovidethenecessarywarranty
service,youwillbedirectedtothenearestotherSABINEAUTHORIZEDDEALERwhichcanprovide
suchservice. OR
b.Shipthedefectiveitem,prepaid, to:
SABINE,INC.
13301HIGHWAY441
ALACHUA,FL 32615-8544
Includetherewithacomplete,detaileddescriptionoftheproblem,togetherwithalegible copyof the
originalPROOF OFPURCHASEand acompletereturn address. UponSabine’sreceipt ofthese
items:
Ifthedefectisremedialunderthelimitedwarrantiesandtheothertermsandconditionsexpressedhave
beencompliedwith,Sabinewillprovidethenecessarywarrantyservicetorepairorreplacetheproduct
andwill return it,FREIGHTCOLLECT,toyou, the purchaser.
Sabine’sliabilitytothepurchaserfordamagesfromanycausewhatsoeverandregardlessoftheform
ofaction, includingnegligence,is limitedtothe actualdamagesup tothegreater of$500.00or an
amountequalto thepurchasepriceofthe productthatcausedthedamageorthatisthesubjectofor
isdirectly related to thecauseof action. Such purchasepricewillbe that ineffectfor the specific
productwhenthecauseof actionarose.Thislimitation ofliabilitywillnotapplyto claimsforpersonal
injuryor damageto realpropertyortangiblepersonal propertyallegedlycausedbySabine’s negli-
gence.Sabinedoes not assume liability forpersonalinjuryor property damage arising out ofor
causedby anon-Sabinealteration or attachment,nordoes Sabineassumeany responsibility for
damageto interconnectednon-Sabine equipmentthatmayresultfrom thenormalfunctioningand
maintenanceoftheSabineequipment.
UNDERNO CIRCUMSTANCES WILLSABINE BELIABLEFORANYLOST PROFITS,LOST
SAVINGS, ANY INCIDENTAL DAMAGES OR ANY CONSEQUENTIAL DAMAGESARISING
OUT OF THE USE OR INABILITY TO USE THE PRODUCT, EVEN IF SABINE HAS BEEN
ADVISEDOF THE POSSIBILITYOFSUCH DAMAGES.
THESELIMITED WARRANTIESAREIN LIEUOFANY ANDALL WARRANTIES,EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
CHANTABILITYANDFITNESSFORAPARTICULARUSE; PROVIDED,HOWEVER,THATIF
THE OTHER TERMS AND CONDITIONS NECESSARY TO THE EXISTENCE OF THE EX-
PRESSLIMITEDWARRANTIES,ASHEREINABOVESTATED,HAVEBEENCOMPLIEDWITH,
IMPLIED WARRANTIES ARE NOT DISCLAIMED DURING THE APPLICABLE ONE-YEAR
PERIOD FROM DATE OF PURCHASE OF THIS PRODUCT.
SOME STATES DO NOTALLOWLIMITATIONON HOW LONGAN IMPLIED WARRANTY
LASTS,ORTHEEXCLUSION ORLIMITATIONOF INCIDENTALORCONSEQUENTIALDAM-
AGES,SOTHEABOVELIMITATIONSOR EXCLUSIONS MAYNOTAPPLYTOYOU. THESE
LIMITEDWARRANTIESGIVEYOU SPECIFICLEGALRIGHTS,ANDYOU MAYALSO HAVE
OTHERRIGHTSWHICH MAYVARYFROM STATETO STATE.
THESE LIMITEDWARRANTIESARETHE ONLYEXPRESSWARRANTIESONTHISPROD-
UCT,AND NOOTHERSTATEMENT,REPRESENTATION,WARRANTYORAGREEMENTBY
ANYPERSONSHALLBEVALIDORBINDINGUPON SABINE.
In theeventofanymodificationordisclaimerofexpress orimplied warranties,or anylimitation
ofremedies, contained hereinconflictswith applicable law,thensuch modification, disclaimeror
limitation,asthecasemaybe,shallbedeemedtobemodifiedtotheextent necessarytocomply with
suchlaw.
Yourremediesfor breachofthesewarrantiesare limitedtothoseremediesprovided herein,and
Sabinegivesthislimitedwarrantyonly withrespect toequipment purchasedin theUnited Statesof
America.
INSTRUCTIONS-WARRANTY REGISTRATION CARD
Mailthe completed WARRANTYREGISTRATION CARD to:
SABINE,INC.
13301HIGHWAY441
ALACHUA,FL32615-8544
OR,registeronlineat www.SabinePro.com
NOTE:KeepthePROOFOF PURCHASE. In the event warrantyserviceisrequired during the
warrantyperiod,youwillneedthisdocument.TherewillbenoidentificationcardissuedbySabine,Inc.
IMPORTANCE OFWARRANTYREGISTRATIONCARDSANDNOTIFICATIONOFCHANGES
OF ADDRESS
Shouldnotificationbecomenecessaryforanyconditionthatmayrequirecorrection,theREGISTRA-
TIONCARD,orinformationsubmittedusingthe ONLINEREGISTRATIONFORM,willhelp ensure
thatyouare contactedandproperlynotified.
Noticeofaddresschanges-Ifyou movefrom theaddressshownontheWARRANTYREGISTRA-
TIONCARDorONLINEREGISTRATIONFORM,youshouldnotifySabineofthechangeofaddress
soasto facilitateyourreceiptofanybulletinsorother formsofnotificationwhichmay becomeneces-
saryin connectionwith anycondition thatmayrequiredisseminationof informationor correction.
You maycontact Sabine directlyby telephoning(386) 418-2000.
Pleasehave the Sabine product nameandserial number available when communicating
withSabine Customer Service.
EXPOSURETO EXTREMELYHIGH NOISE LEVELS MAYCAUSEAPERMANENTHEAR-
INGLOSS. INDIVIDUALSVARYCONSIDERABLYINSUSCEPTIBILITYTONOISEINDUCED
HEARINGLOSS, BUTNEARLYEVERYONEWILLLOSESOMEHEARINGIF EXPOSEDTO
SUFFICIENTLYINTENSE NOISE FORASUFFICIENTTIME. THE U.S.GOVERNMENT’S
OCCUPATIONALSAFETYAND HEALTHADMINISTRATION(OSHA) HASSPECIFIEDTHE
FOLLOWINGPERMISSIBLENOISELEVELEXPOSURES:
DURATION/DAYINHOURS SOUNDLEVELIN dBA,SLOWRESPONSE
890
692
495
397
2 100
1-1/2 102
1 105
1/2 110
1/4orless 115
ACCORDING TO OSHA, ANY EXPOSURE IN EXCESS OF THE ABOVE PERMISSIBLE
LIMITSCOULD RESULT INHEARINGLOSS. EARPLUGSOR PROTECTORSINTHE EAR
CANALS OR OVER THE EARS MUST BE WORN WHEN OPERATING THIS DEVICE IN
ORDERTO PREVENTAPERMANENTHEARINGLOSS, IFEXPOSUREIS INEXCESSOF
THELIMITSASSETFORTHABOVE. TOENSUREAGAINSTPOTENTIALLYDANGEROUS
EXPOSURE TO HIGH SOUND PRESSURE LEVELS, IT IS RECOMMENDED THATALL
PERSONSEXPOSEDTOEQUIPMENT CAPABLE OFPRODUCINGHIGHSOUND PRES-
SURE LEVELS SUCH AS THIS DEVICE BE PROTECTED BY HEARING PROTECTORS
WHILETHIS UNITIS IN OPERATION.
FBX-2020-OpGd-v2.P65
010301 -hto
MADEIN USA www.Sabine.com
Register your Sabine products online at:
www.Sabine.com