Operating
Guide
INSIDE THIS GUIDE:
About the FBX2020-Plus 1-2
FBX2020-Plus Controls 3
Applications 4-5
Understanding Fixed
& Dynamic Filters 6
Operating Instructions 6-8
Troubleshooting Tips 8
Product Specifications 9
Block Diagram 9
Cautions & Warranty 10
Compliance Information 11
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-P
lus 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.
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.
• The FBX2020-Plus's new ClipGuard® adaptive clip level control, with TURBO set-up mode, increases the 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.
QUICK-START OPERATION
For best results, read all operating instructions before using the FBX2020already 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.
Plus
. If you're
READ THE ENTIRE OPERATING GUIDE FOR COMPLETE INSTRUCTIONS.
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.
© 2003 Sabine, Inc.
ClipGuard™ adaptive clip level control is covered under U.S. Patent No. 5821889. Other patents pending.
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ABOUT THE FBX2020-Plus
FREQUENCY RESPONSE: FBX 1/10-Octave Filter Vs. 1/3Octave Graphic EQ Filter (12 dB depth; Log Scale).
FREQUENCY RESPONSE:
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.
A DIRECT HIT ON FEEDBACK! The FBX targets feedback without
taking a big chunk out of your sound. Tests prove that a single 1/3octave EQ slider pulled down 12 dB removes almost half the power
going to the speakers over a two-octave range. And, as this illustration 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.
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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 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 FBX2020Plus, 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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FBX2020-Plus CONTROLS
FRONT PANEL
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.
SIGNAL LEVEL
The LED ladder indicates the signal
strength relative to the FBX's input
clip level.
RESET
Press and hold until 'Dynamic Filter'
LEDs go out to reset the dynamic
filters. Hold until all LEDs go out to
all filters. This also
reset
automatically places the unit into
Turbo mode.
TURBO MODE
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
level light flashes. DO NOT ENTER TURBO
MODE DURING A PERFORMANCE.
SET TOTAL NO.
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.
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.
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 set-up and will stay on
until the button is pressed again
and the LED turns off.
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 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 twoposition push button switch. The
power indicator LED will light
when the FBX is operational.
BACK PANEL
A/C POWER INPUT
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 builtin 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.
INPUTS AND OUTPUTS
1/4" TRS and XLR balanced and unbalanced.
GROUND LIFT
Use this switch to choose between grounded or lifted ground.
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APPLICATIONS
FBX SET-UP FOR MONITORS:
Mix 1
CH A - OUT
CH A - IN
AMP
Mix 2
MIXER
FBX SET-UP FOR ENTIRE MIX:
signal processing
equipment
Right Send
Left Send
MIXER
signal processing
equipment
All other
All other
CH B - OUT
CH B - OUT
CH B - IN
CH B - IN
CH A - OUT
CH A - IN
AMP
AMP
AMP
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