SABINE FBX2420 Specifications

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p e r a t i n g
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Contents
SECTION one — Front & Back Panels
1.1. FBX2420 Front Panel Controls & LED Indicators
1.2. FBX2420 Back Panel Controls & Connections
2
2
2
SECTION two — APPLICATIONS
2.1. FBX Setup for Monitors
2.2. FBX Setup for Entire Mix
2.3. FBX Setup for Single Insert Point
2.4. FBX Setup for Insert Send & Return
3
3
3
3
3
SECTION THREE — ENGINEERING SPECIFICATIONS
3
SECTION FOUR — OPERATING INSTRUCTIONS
4.1. Before You Begin
4.2. How To Operate your FBX1220 / FBX2420
4
4
5
SECTION FIVE — How to use FBX Features
5.1. Input / Output Level Switches
5.2. FBX Filter Control
5.3. Important Operating Considerations
6
6
6
6
SECTION SIX — TROUBLESHOOTING TIPS
7
SECTION seven — FBX Theory & Practice
7.1. Introduction to FBX
7.2. The Advantages of FBX Filters 7.3. Parametric Filters and FBX
7.4. Who Benefits from FBX?
8
8
8
9
9
SECTION EIGHT — Cautions & Warranty
10
Quick Start Setup on back page
SECTION one — Front & Back Panels
1.1. FBX2420 Front Panel Controls & LED Indicators
2
4
1
8
6
3
5
Note: FBX1220 front and back panels
use the same controls and
input/output configuration
7
1. SETUP
Press and hold this button to begin the FBX setup mode. Filter
LEDs (light emitting diodes) will flash 5 times and the SETUP
LED will begin to flash. You are now ready to set FBX filters.
5. RESET DYNAMICS & DYNAMIC FILTER TIMER
Press and hold this button until the Dynamic filter flash and
LEDs go off to reset all Dynamic filters. See Section 5.2.4. for
enabling and setting the Dynamic Filter Timer.
2. READY
The READY LED lights when the automatic FBX setup process
has completed, or the READY button has been pressed. This
indicates your unit is ready for operation. The total number of
filters available for feedback filtering is 12; in the factory default
setting, your unit will automatically enter READY mode when
the tenth filter is set. Alternatively, you may enter READY status
with fewer Fixed FBX filters in place, simply by pressing the
READY button at any time. Press READY again to lock the
Fixed filters.
6. NUMBER FIXED
Set the number of available fixed filters by pressing the NUMBER FIXED button (6) until the LEDs stop flashing, then release
it. The LEDs (8) will begin to light in sequence. When the LED
corresponding to the desired number of fixed filters lights, press
the Number Fixed button to register your selection.
3. 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.
4. SIGNAL LEVEL
The LED ladder indicates the signal strength relative to the
FBX's input clip level.
7. 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.
8. 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.
1.2. FBX2420 Back Panel Controls & Connections
13
9
11
10
12
13
14
12
13
14
15
13
16
15
16
9. A/C Power Input
The FBX1220 & FBX2420 Series is factory configured to
operate at 230 VAC. Using the wrong input voltage may cause
permanent damage to the unit and will void the warranty.
11. Power Switch
Previous settings retained during power-off.
10. Fuse
This equipment is fitted with an IEC power inlet incorporating a
built-in fuse holder. To change the fuses in this socket:
13. Input/Output Level Switches
Set to match your desired Input/Output level configurations.
For unity gain set both switches to the same postion.
1.Disconnect the power cord from the unit.
2.Pull out the fuse holder and remove the old fuse.
3.Install a new fuse into the holder. Replace only with one
of the following fuses:
• 230 VAC: 0.1 A, 10 W, 0.160 A SB fuse
4.Refit the fuse cover.
2
12. Quarter-inch Output
TRS balanced or TS Unbalanced output .
14. XLR Output
XLR balanced output.
15. Quarter-inch Input
TRS balanced or TS unbalanced input.
16. XLR Input
XLR balanced input.
SECTION two — APPLICATIONS
Monitor Mix 1
2.1. FBX Setup for Monitors
Monitor Mix 2
Ch. B
OUT
2.2. FBX Setup for Entire Mix
Ch. B
IN
Ch. A
IN
Ch. B
IN
Ch. A
IN
Ch. A
OUT
Right Main Send
Left Main Send
All other Signal
Processing
Ch. B
OUT
2.3. FBX Setup for Single Insert Point
Ch. A
OUT
TS "Y" Connector
IMPORTANT NOTE
Ch. 1
• Mixing balanced and unbalanced connections may result
in a 6 dB loss of gain.
Ch. 2
Ch. B OUT
< Low Z >
< High Z >
< Insert >
Ch. A OUT
Ch. B IN
Ch. A IN
TS "Y" Connector
TRS Connector
TRS Connector
Y Insert Cords (TRS to TS + TS)
2.4. FBX Setup for Insert Send & Return
Ch. 1
TS or TRS Connectors
< Insert
Send
Insert >
Return
•
• Use
Use aa ¼-inch
¼-inch TRS
TRS plug
plug for
for
balanced
balanced sends/inserts.
sends/inserts.
Ch. B OUT
Ch. A IN
Ch. B IN
•
• Use
Use aa ¼-inch
¼-inch TS
TS plug
plug for
for
unbalanced
unbalanced sends/inserts.
sends/inserts.
Ch. 2
Insert >
Return
Ch. A OUT
IMPORTANT
IMPORTANT NOTE
NOTE
< Insert
Send
•
• Mixing
Mixing balanced
balanced and
and unbalunbalanced
anced connections
connections may
may result
result
in
in a 6 dB
dB loss
lossof
ofgain.
gain.Refer to
section 5.2.
TS or TRS Connectors
Tests performed using an Audio Precision
System One model 322 or equal.
Filters
• 12 independent digital notch
filters per channel, controlled automatically from 40 Hz to 20 KHz.
• Filter width: user-controllable - either
1/10 or 1/5 octave*, constant "Q"
• Resolution: 1 Hz
• Time required to find and eliminate
feedback: 0.4 seconds, typical @ 1
KHz
• Number of Dynamic vs. Fixed
filters per channel: user selectable. Last configuration stored in
memory.
*Below approximately 200 Hz the feedback filters
become slightly wider to increase the feedback and
rumble capture speed at these low frequencies.
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 >40K Ohms, PIN 2 high
• Output Impedance: Balanced or
unbalanced 150 Ohms nominal, PIN
2 high
• Bypass: True power off bypass
• Headroom: +23 dB peak @ 4 dBV
nominal input, balanced
• I/O Connectors: XLR-3 and 1/4"
TRS
PERFORMANCE***
• Frequency response: 20 Hz – 20
KHz +/- 0.3 dB
• Gain matching: +/- 0.2 dB
• Spectral Variation: + .25 dB, 20
Hz to 20 KHz
• SNR - Dynamic Range: >100 dB
• THD: .005% at 1 KHz
< 0.01% 20 Hz – 10 KHz
< 0.025% 10 KHz – 20 KHz
• Dynamic Range: >105 dB
POWER INPUT
• 230 VAC: 200 – 240 VAC 50/60
Hz
FUSE
• 230 VAC, 0.1 A, 10 W, 0.160 A SB
fuse
DIMENSIONS
• 1-U rack mount; 19 x 1.75 x 6.25 in.
nominal (rack mountable); 48.3 x 4.5
x 15.9 cm nominal
WEIGHT
• 8.0 lbs. (3.6 kg) nominal
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© 2008 Sabine, Inc.
SECTION THREE — ENGINEERING SPECIFICATIONS
SECTION FOUR — OPERATING INSTRUCTIONS
4.1. Before You Begin
These instructions apply to both the FBX1220 and the FBX2420. The 2420 is a
dual-mono version of the 1220. Your FBX Feedback Exterminator will improve any
sound reinforcement system. The instructions presume that you are familiar with the
fundamentals of sound reinforcement.
4.1.1. Where the FBX fits in your sound system:
The most common patch point 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. An even better solution is on a mixer insert point for
a single channel, or a subgroup (see application diagrams in Section Two — Applications). This targets the feedback control to the mics that need it.
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 (TRS) outputs, you must use that
type of connector. If you don’t, you may experience a loss of gain (up to 6 dB) when
using the FBX. This can occur if either side of the balanced output is grounded at
any point (or when mixing balanced and unbalanced inputs and outputs).
4.1.2. 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; however, a
graphic equalizer 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.
4.1.3. Understanding FIXED and DYNAMIC filters
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. In addition, you can LOCK the fixed filters so
they do not get any deeper. Locked fixed filters are no longer adaptive. 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 most applications, the optimal setting
is nine FIXED and three DYNAMIC FILTERS. This is the factory default.
4.1.4. Setup & Ready
Your FBX Feedback Exterminator is either in Setup, Ready, or Bypass mode.
Setup Mode: It’s quick and quiet, but use this mode for setup only – do not use
the FBX for your program while in Setup mode. Think of Setup mode as your
key to achieving one of the main benefits of the FBX: getting more gain before
feedback. In Setup mode you will be raising the gain of your system so the FBX
can place transparent filters (Fixed Filters) that will allow you to get all the gain
you need for a loud and clear show. In Setup the FBX is very sensitive so do not
talk into the mics during setup, and try to keep room noise to a minimum. If the
room is noisy, then go into Ready mode and raise your gain while the fixed filters
are still unlocked (flashing Ready LED).
Ready Mode: Let the show begin. Your fixed filters are eliminating feedback
and giving you extra gain, and your dynamic filters are ready to jump on any new
feedback during the show. In this mode your fixed filters are either locked (red
LEDs) or unlocked (amber LEDs). We recommend locking your fixed filters for
the show. But if you don’t have time for the Setup mode, or if the room is just too
noisy during setup, then you can start off by unlocking the fixed filters. Leaving
the fixed filters unlocked allows them to get deeper if needed, which can be handy
if you need to get more gain before feedback. But once your system stabilizes we
recommend you lock the fixed filters for the duration of the show!
4
4.2. How To Operate your FBX1220 / FBX2420
Place equipment
make connections.
Follow these &
procedures
to get maximum gain before feedback
1
a. Patch your FBX1220 or FBX2420 into system and make all connections (refer to pages 2 and 3 for connection options).
b. Place speakers and microphones in performance positions.
c. Set Input and Output levels on FBX back panel (see Section 5.1.1.
for details). Start with all buttons pushed in.
d. If you are using a graphic EQ, adjust only for the desired tonal qualities, but DO NOT NOTCH FOR FEEDBACK.
e. Adjust the level for each mixer channel, and set the sound system’s
master volume to minimum.
2
3
Push SETUP button until all LEDs stop flashing and the
SETUP light flashes on its own. Setup mode clears all Fixed &
Power Tips
a. Set up one FBX channel at a
time.
b. DO NOT TALK INTO YOUR SYSTEM while in Setup mode.
c. See Section 5.2. FBX Filter Control for information on:
• Changing the number of Fixed
vs. Dynamic filters
• Selecting and mixing 1/10- &
1/5-octave filters
• Enabling and setting the Dy-
Dynamic filters. Do not use Setup mode during your performance.
Slowly raise the gain on the mixer or amp until the FBX
eliminates the first few feedback tones.
DO NOT TALK INTO THE MICS. The FBX will quickly begin to find and remove
feedback. The first Fixed filter set will be heard as a quiet feedback chirp and
shown as an amber LED. As you slowly raise the gain, more feedback chirps
will be heard, and more amber LEDs will light.
a. If you are using stationary microphones:
Continue raising the gain until all filter LEDs cycle back and forth in
sequence. This is your indication that the FBX is exiting setup mode.
IMPORTANT: Reduce gain slightly. You are now in READY (performance) mode, with the Fixed filters locked and the blue Ready light
on. Begin the show!
Front panel filter LEDs
lighting as gain is raised
and Fixed filters are set.
b. If you are using wireless microphones:
c. You may quit Setup mode at any time prior to its automatic exit by simply
pressing the READY button (blue READY LED will flash). Press it again at
any time to lock the Fixed filters (blue READY LED stays on). Whether locked
or unlocked, pressing the READY button before Setup mode automatically
finishes will enable ready-to-operate status, but with fewer fixed FBX filters
in place. Dynamic FBX filters are still available to eliminate new feedback,
regardless of how or when SETUP mode is exited. Begin the show!
4
If you do not have time to use Setup Mode:
Push the READY button -- the blue LED flashes indicating the fixed filters are
unlocked. Begin your show, and once several fixed filters are set we recommend you lock them by pushing ready again (blue LED stays lit). You won't
get all the potential benefit of increased gain before feedback, but you will get
automatic feedback control during your performance.
FILTER COLOR KEY
FBX Filters
LEDs
Ready LED
Fixed, Locked
Fixed, Unlocked
BLUE
RED
AMBER
Steady BLUE
Flashing
Fixed & Dynamic Filters
See Section 4.1.3. for details on
the differences between Fixed and
Dynamic FBX filters, and Section
5.2.2. for instructions on changing
the balance of Fixed versus Dynamic filters.
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You can get more gain in a variety of locations. To do this, lower the system
gain after the first few filters are set, then move the microphone to another area
where it will be used and raise the gain slowly as before. Repeat this process
while you continue raising the gain until all filter LEDs cycle back and forth
in sequence. This is your indication that the FBX is exiting setup mode.
IMPORTANT: Reduce gain slightly. You are now in READY (performance) mode, with the Fixed filters locked and the blue Ready light
on. Begin the show!
5
SECTION FIVE — How to use FBX Features
5.1. Input / Output Level Switches
Use the two-position switches on the back panel of your FBX1220 / FBX2420 to compensate for input level or output level
requirements. NOTE: For unity gain (recommended), set the channel's input & output level switches to the same setting.
5.1.1. Setting Levels: Set both Input & Output switches the same for Unity
Gain
position
OUT
IN
input level switches
output level switches
Accepts low level input up to +6 dBU
Outputs at low level, for sending signal to low-level devices or some insert
points. See Section 2 for more information on applications.
Accepts high level input up to +24 dBU
Outputs at high level, for most line-level devices. See Section 2 for more
information on applications.
5.2. FBX Filter Control
5.2.1. 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. You can mix filter widths: start with a few filters at 1/5 for the worst feedback points, then switch to 1/10.
5.2.2. Setting Number of Fixed vs. Dynamic Filters
To change the number of Fixed filters from the factory default of 9 Fixed and 3 Dynamic per channel, push the READY button
for 4 seconds. The filters LEDs will flash 4 times and then go out. Release the READY button, and the LEDs will begin to light
in sequence. When the LED corresponding to the desired number of Fixed filters lights, press the READY button again.
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 filters.
5.2.3. Resetting FBX Filters
All FBX filters: To reset all FBX filters, follow the directions in Section 4.2.
Dynamic FBX filters only: To reset only Dynamic filters, press RESET DYNAMICS until the current Dynamic filter LEDs flash and then turn off. Release
the button.
5.2.4. Dynamic Filter Timer
The Dynamic Filter Timer, when enabled, automatically resets Dynamic filters after a user-selected time has passed (refer to
Timer Settings chart at right).
5.2.4.1. Set the Dynamic Filter Timer
1. Press and hold the RESET DYNAMICS button. The Dynamic LEDs flash twice and reset. Continue holding the
button and the current Dynamic Filter Timer setting will flash twice (filter LEDs 1-5, see
Filter Timer Chart at right).
2. Release the RESET DYNAMICS
button and filter LEDs 1-5 will
cycle through the possible timer
settings.
3. Press RESET DYNAMICS again
at the desired timer setting. LEDs
will flash twice (including filter LEDs
indicating the current timer setting). Your Dynamic Filter Timer is now set. The timer starts
individually for each Dynamic filter.
5.3. Important Operating Considerations
5.3.1. Power-Off 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.
5.3.2. Bypass Mode
The FBX has a true power-off bypass. The signal is unaffected in Bypass mode even if the unit is turned off. Note that if a combination of balanced and unbalanced inputs and outputs is used, the signal may be disconnected or attenuated in Bypass.
5.3.3. Setup Mode
NOTE: Setup mode is for pre-performance audio setup only, and will cause distortion in your audio program if left on
during performance. You must follow the setup procedure outlined in the previous section, and do not play program or talk
into the mics during Setup. Otherwise the FBX will clip and filters may be set improperly (Clip level is set to the lowest level
6
so the feedback clips quickly; therefore, your program will also be clipped in setup mode). Be sure the blue Ready light is
on (either flashing or steady) and if it isn’t, press the READY button before your program begins. You’ll know the FBX1220
/ FBX2420 is in setup mode when the SETUP button is lit. NOTE: You can manually override Setup mode if necessary.
That's right -- press the Ready button!
5.3.4. Mobile vs. Stationary Microphones
One significant advantage offered by the Sabine family of FBX Feedback Exterminator products is their ability to adapt to
changing acoustical relationships involving sound system components in various 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
performance area. 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.
For this reason we recommend setting FBX filters for mobile microphones by moving to the various possible microphone
locations and setting filters for those locations. As the Setup instructions show, raise the system gain and set the FBX filters
in each predictable location.
In some situations, increasing the number of dynamic filters (versus fixed FBX filters) may allow a second layer of defense
against new feedback from new locations. This technique is recommended if you cannot predict where the performer may roam.
But fixed FBX filters placed in the setup procedure are still your best bet because the feedback filters are already set.
SECTION SIX — TROUBLESHOOTING TIPS
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
disconnected 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. Q. Why does one of the FILTER ACTIVITY LEDs blink?
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 setup, 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 with the unit in Bypass.
If the venue is noisy press the Ready button once before
taking the unit out of Bypass. Then take it out of Bypass and
proceed with the normal initiation procedure.
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, re-initialize the system and
make sure the READY button LED is on steadily.
Q. Why does my program sound clipped and distorted?
A. Make sure you are not in Setup mode. Setup mode turns off
automatically after the first dynamic filter is set, or you can
turn it off manually by pressing the READY button. See Section 5.3.3. for information on Setup mode.
Q. Can I patch two FBX channels together for twice the
filters?
A. Yes; connect the output of one FBX channel to the input of
the other channel. Patch the FBX between the output of the
mixer and the input of a power amp, and set up the channels
sequentially. When combining channel A with channel B on an
FBX2420, set all channel A filters fo fixed (see section 5.2.2)
and bypass channel B. Follow normal setup procedure on
channel A, and lock the fixed filters (see section 4.2). Then
follow the standard setup procedure channel B, which should
have a few dynamic filters available.
Q. Why doesn't the FBX1220 & FBX2420 Series filter feedback immediately?
A. Four possible reasons:
1. Lower frequencies may take longer than higher ones.
2. Check input level of signal at the unit and set 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.
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© 2008 Sabine, Inc.
Q. Can I place the FBX in the mixer’s EQ loop?
A. Yes.
SECTION seven — FBX Theory & Practice
7.1. Introduction to FBX®
WHY FBX? Feedback is certainly the most pervasive challenge to the audio industry. The
potential appearance of sudden, loud, out-of-control feedback is every sound engineer’s
and musician’s nightmare. Unlike more subtle audio quality problems or shortcomings,
feedback is embarrassingly obvious — it disturbs the performer, the audience, and the
technician, and can damage equipment and just generally ruin your day.
Feedback is a potential problem in any amplified sound system that places a microphone
or pickup in proximity to a loudspeaker. Poor acoustical conditions or misguided use by
unsophisticated sound system operators only aggravate the situation. To make matters still
worse, a non-Sabine variety of wireless microphone adds yet another level of feedback
danger to the picture. Since feedback erupts whenever the distance, location, and gain
relationships between a speaker and a microphone reach a critical combination, a mic
that can move anywhere results in an ever changing potential for feedback. A step in the
wrong direction may change a clear sound to a piercing shriek in less than a second.
This enhanced potential for feedback with a wireless system gets worse if lavalier microphones are used. Such microphones are usually placed farther from the mouth than
handheld or head set microphones, thus requiring more gain. Also, the polar pattern
of a lavalier microphone is frequently omnidirectional. Thus, the likelihood of feedback
increases, due to the microphone’s increased off-axis sensitivity to the sound emanating
from the loudspeakers.
The Sabine FBX1220 and FBX2420 systems solve feedback problems by precise attenuation of very narrow bands of feedback-prone frequencies. The process is automatic,
simple to use, adaptable to changing acoustical conditions and relationships, powerful in
its application, and has minimal consequences to the audio fidelity of the signal. We call
this automatic filter an FBX Feedback Exterminator® filter, or FBX filter for short.
-10 dB cut at 500, 630, 1K, 1.25K, 1.6K & 2K Hz
If the graphic EQ really had 1/3 octave
filter widths, the frequency response curve
would vary 6 dB between sliders. This
would ruin the sound.
Graphic EQs usually use one-octavewide overlapping filters that provide much
smoother frequency response curves.
Notice that the overlapping filters add
together to cut -16 dB when the sliders
are only pulled down -10 dB.
7.2. The Advantages of FBX Filters
Before the invention of FBX, the most common device for controlling feedback was the
31-band graphic EQ. However, an FBX filter offers three distinct advantages over graphic
filters.
1. First and most obvious is the automatic nature of FBX filters. When feedback occurs,
FBX responds more quickly than even the most experienced engineer. Automatic
FBX placement works even in the presence of audio program material, intelligently
distinguishing feedback from music or speech.
2. A second advantage is that FBX micro-filters are precisely placed anywhere feedback
occurs (with 1 Hz resolution), while graphic EQ filters are limited to 31 fixed center
points. An FBX filter represents a direct hit on feedback! In contrast, a graphic EQ
filter can only approximate the exact frequency of the feedback, and the filter (or filters)
with the closest center frequency must be pulled down. Such filters are deepest at
their centers, and such imprecise attenuation takes a big (and unnecessary) chunk
out of your sound (see figure 7a).
3. Increased clarity and gain-before-feedback are further accomplished by the third and
most important advantage of FBX: Sabine’s micro-filters are ten times narrower than
31-band EQ filters. Using FBX micro-filters will return up to 90 percent of the power
removed by EQ filters. Here’s a good place to make a very important distinction. Graphic EQ filters are typically
called “1/3-octave,” but it’s important to understand that this term refers to the spacing of
the filter centers (1/3-octave apart), and not the width of the filter (usually a full octave).
Graphic filters thus overlap one another, and affect frequencies well above and below
the center point frequency, including frequencies of adjacent bands. This makes graphic
equalizers very practical tools for shaping sound “with broad strokes,” such as dialing in
overall system EQ, but results in destructive audio quality overkill when they are used
to eliminate feedback. A graphic equalizer would need more than 10,000 narrow-band
sliders to be as precise and powerful as your FBX.
As an example of the power of FBX, figure 7b shows test results measured with a PA set
up consisting of a microphone, mixer, FBX Feedback Exterminator®, power amp and two
speakers. The system’s gain was first raised until the FBX removed nine feedback points.
Next, the FBX was replaced with a 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 and are compared in figure 7b. Note how much more
of the program (the “good audio”) is eliminated using an EQ — whereas only feedback
is eliminated using FBX filters.
7.3. Parametric Filters and FBX
8
Fig. 7a.
Of course, many savvy sound engineers, realizing the limitations of
graphic equalizers in removing problem feedback, prefer to use a
different type of equalizer, called a parametric EQ, for such applications. If you’re one such audio engineer, you’ll be comforted to know
that FBX filters share much in common with parametrics.
Compared to graphic filters, parametrics allow more precise adjustments — specifically, control of filter width, the amount of boost or
cut, and the mid-band frequency of the filter. This greater precision,
however, comes at a price, as parametric filters are not nearly as
intuitive or simple to use as graphic equalizers.
Nothing, however, is easier to use than an FBX filter, which enjoys
the precision of a parametric filter, yet deploys instantly and automatically whenever feedback is detected. Effectively, an FBX filter is
a parametric filter set to a tenth-octave width, restricted to cut-only
activity, and automatic in its choice of frequency band.
7.3.1. Dynamic FBX Filters
Dynamic FBX filters also set automatically, but can change frequency, on a rotating basis,
as the need arises. To help distinguish dynamic from fixed filters, consider the example
of a speaker using a wireless lavalier microphone, who walks under a ceiling speaker for
the first time. In so doing, he enters a location-specific feedback zone, where it’s possible
that a problem frequency may have escaped detection and notching by a fixed filter. If
all fixed filters have been deployed, a dynamic filter will be set automatically as soon as
feedback appears, solving the problem. Great! But what happens when the speaker then
moves away from the ceiling speaker, and close to a floor monitor? Feedback from the
ceiling speaker is no longer a problem, but a new frequency starts to squeal. If all fixed
and dynamic FBX filters are already set, a dynamic filter will change, to adjust to the new
location. An FBX dynamic filter thus stands guard if new problem feedback arises after
all available filters have been set, providing a deeper and more flexible level of protection
against the dreaded surprise of feedback. Other than the ability to change frequency, a
dynamic filter is equivalent to a fixed filter.
7.3.2. Balancing Fixed & Dynamic Filters
Your FBX1220, and each channel of your FBX2420, offer a total of 12 FBX filters (combined fixed and dynamic), which can be used as needed to exterminate feedback. After
years of experience and experimentation, Sabine has settled upon a default balance of
9 fixed and 3 dynamic filters, set at the factory. This default condition can be changed to
any combination you require.
If you follow setup instructions for setting FBX filters, your FBX1220/FBX2420 will automatically exit SETUP mode (enter READY status) after all fixed filters and the first dynamic
filter are set. In the default condition, this means you will have set ten filters (nine fixed
and one dynamic), with two dynamic filters not set and ready to catch new feedback. If
you wish to set fewer filters, press the READY button before SETUP automatically exits,
after you have set enough filters to safely achieve your desired gain level. In that case, in
the factory default condition, you will have three dynamic filters plus the remaining unused
(and unlocked) fixed filters available to catch new feedback.
7.3.3. FBX Filter Width
Sabine’s experience and testing with filters and sound quality led us to decide upon a
default FBX filter width of .10 (one-tenth) octave as the optimal notch width. This eliminates feedback very well without affecting music programs. If, with all filters properly set,
feedback is still a problem, FBX filters may be set to .20 (one-fifth) octave width. This
wider filter setting will potentially control more feedback frequencies, especially when they
are clustered, but this wider filter may also affect music programs slightly. For this reason
the wider setting is generally considered to be appropriate where speech (less demanding
than music) is the primary application. You can change FBX filter widths by pressing the
FIFTH OCTAVE button on the front panel. Note that the width of any filter will always be
determined by the position of the switch at the time the filter is created.
7.4. Who Benefits from FBX?
Virtually every sound system will be improved with the Sabine feedback control. Singers
and presenters who do not have sound technicians can now increase their monitor or house
system volume so they can hear themselves clearly and with full fidelity, without worrying if
their microphones will suddenly squeal if they move to the wrong place.
© 2008 Sabine, Inc.
Auditoriums and churches of all sizes will enjoy reliable feedback control. Hotels and conference centers around the world can offer meeting rooms with microphones that won’t howl
during programs. Sabine FBX systems can be installed in theaters, schools, sports arenas,
courtrooms, teleconferencing rooms, intercoms or interactive remote classrooms — anywhere
one or multiple microphones are used.
LIT-FBX1220-1224-OP-EN-080208.pmd - ks
9
SECTION EIGHT — Cautions & Warranty
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 relié à la terre.
Attention! Risque de choc électrique; ne pas ouvrir.
Attention! Risque de choc; ne pas oter les capots. Aucune pièce accessible à l'intérieur. S'addresser à un technicien qualifié.
Attention! Pour réduire le risque d'incendie ou de choc électrique, ne
pas laisser l'appareil sous la plouie ou à l'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 interference; 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
interference 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 determined 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 Regulations 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.
Warning!
The FBX1220 & FBX2420 Series 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 FBX1220 & FBX2420 Series is supplied with one of the following AC power cords:
Japan
100 VAC
U.S./North America 120 VAC
Continental Europe 230 VAC
United Kingdom
240 VAC
Australia 240 VAC
Caution!
Replace the fuse with a fuse of exactly the same rating
specified on the rear of the product.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Read all safety and operating instructions before using this product.
All safety and operating instructions should be retained for future
reference.
Obey all cautions in the operating instructions and on the unit.
All operating instructions should be followed.
Use only shielded audio and data cables.
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.
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.
This product should not be placed near a source of heat such as a
stove or radiator.
Connect only to a power supply of the type marked on the unit adjacent
to the power entry module.
Never break off the ground pin on the power supply cord.
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.
The power supply cord should be unplugged when the unit is to be
unused for long periods of time.
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.
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.
10
CAUTION
EXPOSURE TO EXTREMELY HIGH NOISE LEVELS MAY CAUSE A PERMANENT HEARING
LOSS. INDIVIDUALS VARY CONSIDERABLY IN SUSCEPTIBILITY TO NOISE INDUCED
HEARING LOSS, BUT NEARLY EVERYONE WILL LOSE SOME HEARING IF EXPOSED
TO SUFFICIENTLY INTENSE NOISE FOR A SUFFICIENT TIME. THE U.S. GOVERNMENT’S
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) HAS SPECIFIED THE
NOISE LEVEL EXPOSURES AT RIGHT AS PERMISSIBLE :
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 FORTH ABOVE. TO ENSURE AGAINST POTENTIALLY DANGEROUS
EXPOSURE TO HIGH SOUND PRESSURE LEVELS, IT IS RECOMMENDED THAT ALL PERSONS EXPOSED TO EQUIPMENT CAPABLE OF PRODUCING HIGH SOUND PRESSURE
LEVELS SUCH AS THIS DEVICE BE PROTECTED BY HEARING PROTECTORS WHILE
THIS UNIT IS IN OPERATION.
DURATION PER DAY, HOURS
SOUND LEVEL dBA SLOW RESPONSE
90
92
95
97
100
102
105
110
115
8
6
4
3
2
1-1/2
1
1/2
1/4 or less
http://www.osha.gov
1926.52(d)(1)
Limited Warranty
Ces clauses de garantie ne sont vaiables qu’aux Etats-Unis et au Canada. Dans tous les autres
pays, les clauses de garantie et de maintenance sont fixees par le distributeur national et assuree par lui selon la legislation en vigueur.
Diese Garantie ist nur in den USA and Kanada gultig. Alle Export-Produkte sind der Garantie
und dem Service des Importeurs des jewelligen Landes untervorfen.
Esta garantia es valida solamente cuando el producto es comprado en E.U. continentales o en
Canada. Todos los productos que sean comprados en el extranjero, estan sujetos a las garantias
y servicio que cada distribuidor autorizado determine y otrezca en los diferentes paises.
ONE-YEAR LIMITED WARRANTY/REMEDY
SABINE, INC. (“SABINE”) warrants this product to be free from defects in material and workmanship for a period of one (1) year from date of purchase PROVIDED, however, that this limited
warranty is extended only to the original retail purchaser and is subject to the conditions,
exclusions and limitations hereinafter set forth:
CONDITIONS, EXCLUSIONS AND LIMITATIONS OF LIMITED WARRANTIES
These limited warranties shall be void and of no effect if:
a.The first purchase of the product is for the purpose of resale; or
b.The original retail purchase is not made from an AUTHORIZED SABINE DEALER; or
c.The product has been damaged by accident or unreasonable use, neglect, improper service
or maintenance, or other causes not arising out of defects in material or workmanship; or
d.The serial number affixed to the product is altered, defaced or removed; or
e.The power supply grounding pin is removed or otherwise defeated. In the event of a defect in material and/or workmanship covered by this limited warranty, Sabine will repair the defect
in material or workmanship or replace the product, at Sabine’s option; and provided, however, that, in any case, all costs of shipping, if necessary, are paid by you, the purchaser.
WARRANTY REGISTRATION CARD SHOULD BE COMPLETED AND RECEIVED BY SABINE
WITHIN FOURTEEN (14) DAYS OF THE DATE OF YOUR PURCHASE.
In order to obtain service under these warranties, you must:
a.Bring the defective item to any Authorized SABINE DEALER and present therewith the
ORIGINAL PROOF OF PURCHASE supplied to you by the AUTHORIZED SABINE DEALER
in connection with your purchase from him of this product. If the DEALER is unable to provide
the necessary warranty service, you will be directed to the nearest other SABINE AUTHORIZED
DEALER which can provide such service. OR
b.Ship the defective item, prepaid, to:
SABINE, INC.
13301 HIGHWAY 441
ALACHUA, FL 32615-8544
Includetherewith a complete, detailed description of the problem, together with a legible copy
of the original PROOF OF PURCHASE and a complete return address. Upon Sabine’s receipt
of these items:
a.If the defect is remedial under the limited warranties and the other terms and conditions
expressed have been complied with, Sabine will provide the necessary warranty service to
repair or replace the product and will return it, FREIGHT COLLECT, to you, the purchaser.
b.Sabine’s liability to the purchaser for damages from any cause whatsoever and regardless
of the form of action, including negligence, is limited to the actual damages up to the greater
of $500.00 or an amount equal to the purchase price of the product that caused the damage
or that is the subject of or is directly related to the cause of action. Such purchase price
will be that in effect for the specific product when the cause of action arose. This limitation of liability will not apply to claims for personal injury or damage to real property or tangible
personal property allegedly caused by Sabine’s negligence. Sabine does not assume liability
for personal injury or property damage arising out of or caused by a non-Sabine alteration
or attachment, nor does Sabine assume any responsibility for damage to interconnected
non-Sabine equipment that may result from the normal functioning and maintenance of the
Sabine equipment.
UNDER NO CIRCUMSTANCES WILL SABINE BE LIABLE FOR ANY LOST PROFITS, LOST
SAVINGS, ANY INCIDENTAL DAMAGES OR ANY CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PRODUCT, EVEN IF SABINE HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
THESE LIMITED WARRANTIES ARE IN LIEU OF ANY AND ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR USE; PROVIDED, HOWEVER, THAT IF THE
OTHER TERMS AND CONDITIONS NECESSARY TO THE EXISTENCE OF THE EXPRESS
LIMITED WARRANTIES, AS HEREINABOVE STATED, HAVE BEEN COMPLIED WITH, IMPLIED
WARRANTIES ARE NOT DISCLAIMED DURING THE APPLICABLE ONE-YEAR PERIOD
FROM DATE OF PURCHASE OF THIS PRODUCT.
SOME STATES DO NOT ALLOW LIMITATION ON HOW LONG AN IMPLIED WARRANTY LASTS,
OR THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL 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,
AND NO OTHER STATEMENT, REPRESENTATION, WARRANTY OR AGREEMENT 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 limitation
of remedies, contained herein conflicts with applicable law, then such modification, disclaimer
or limitation, as the case may be, shall be deemed to be modified to the extent necessary to
comply with such law.
Your remedies for breach of these warranties are limited to those remedies provided herein,
and Sabine gives this limited warranty only with respect to equipment purchased in the United
States of America.
INSTRUCTIONS — WARRANTY REGISTRATION
• Mail the completed WARRANTY REGISTRATION CARD to:
SABINE, INC.
13301 HIGHWAY 441
ALACHUA, FL 32615-8544
• Or, register online at www.Sabine.com
IMPORTANT: Be sure to keep the PROOF OF PURCHASE. In the event warranty service is
required during the warranty period, you will need this document. There will be no identification
card issued by Sabine, Inc.
IMPORTANCE OF WARRANTY REGISTRATION & NOTIFICATION OF ADDRESS CHANGE:
a.Should notification become necessary for any condition that may require correction, the
REGISTRATION CARD will help ensure that you are contacted and properly notified.
b.Notice of address changes — If you move from the address shown on the WARRANTY
REGISTRATION CARD, you should notify Sabine of the change of address so as to facilitate
your receipt of any bulletins or other forms of notification which may become necessary in
connection with any condition that may require dissemination of information or correction.
You may contact Sabine directly by telephoning (386) 418-2000.
Please have the Sabine product name and serial number available when communicating with
Sabine Customer Service.
© 2008 Sabine, Inc.
THIS LIMITED WARRANTY VALID ONLY WHEN PURCHASED AND REGISTERED IN THE
UNITED STATES OR CANADA. ALL EXPORTED PRODUCTS ARE SUBJECT TO WARRANTY
AND SERVICES TO BE SPECIFIED AND PROVIDED BY THE AUTHORIZED DISTRIBUTOR
FOR EACH COUNTRY.
LIT-FBX1220-1224-OP-EN-080208.pmd - ks
11
1
2
action
Push & Hold
SETUP
Do Not Talk
into Mics!
3
When Filter LEDs
cycle left & right,
Stop Raising Gain
Raise Gain
Slowly
4
Or...
Push READY
anytime to exit
Setup Mode
controls
For complete instructions, please read the operating guide!
SABINE FBX SETUP
Your mixer
STOP
led status
fixed
LEDs will flash 5 times, followed by the SETUP
button LED flashing. You are now in FBX Setup
mode. Do not speak into the mic or play program
though the system.
details
Stop raising gain when all filter LEDs light back
and forth in sequence and turn red; the first
Dynamic filter (green LED) is also set. Setup has
now completed. You are ready to go!
Important: Reduce gain slightly. This will be
your maximum gain setting.
Raise gain slowly. Fixed filter LEDs will flash
amber and then remain lit one at a time as
filters are set.
Wireless Mics: If you are using a wireless mic,
stop raising gain after a few filters and move
the microphone to another performance area;
continue slowly raising gain and repeat.
Unlocked
Setup Mode
Unlocked
Setup Mode
Locked
Ready Mode
Unlocked
Ready Mode
Push READY button at any time to exit Setup
mode. You are ready to go. The blue LED will
flash. Push READY again at any time to Lock
Fixed filters - the blue LED stays lit. See the
operating guide for more information on locking
fixed filters.
Register your FBX equipment
online at Sabine.com
Sabine, Inc. • 13301 NW US Highway 441 • Alachua, Florida 32615-8544 USA • Phone: (386) 418-2000 • Fax: (386) 418-2001