Behringer Music Mixer DSP1100P User Manual
User´s Manual E  
Bedienungsanleitung D  
Version 1.0 October 1998  
www.behringer.de  
Download from Www.Somanuals.com. All Manuals Search And Download.  
SAFETY INSTRUCTIONS  
CAUTION: To reduce the risk of electrical shock, do not remove  
the cover (or back). No user serviceable parts inside;  
refer servicing to qualified personnel.  
WARNING: To reduce the risk of fire or electrical shock, do not  
expose this appliance to rain or moisture.  
E
This symbol, wherever it appears, alerts  
you to the presence of uninsulated  
dangerous voltage inside the enclosure  
- voltage that may be sufficient to con-  
stitute a risk of shock.  
This symbol, wherever it appears, alerts  
you to important operating and mainte-  
nance instructions in the accompanying  
literature. Read the manual.  
DETAILED SAFETYINSTRUCTIONS:  
All the safety and operation instructions should be read before the appliance is operated.  
Retain Instructions:  
The safety and operating instructions should be retained for future reference.  
Heed Warnings:  
All warnings on the appliance and in the operating instructions should be adhered to.  
Follow instructions:  
All operation and user instructions should be followed.  
Water and Moisture:  
The appliance should not be used near water (e.g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wet  
basement, or near a swimming pool etc.).  
Ventilation:  
The appliance should be situated so that its location or position does not interfere with its proper ventilation.  
For example, the appliance should not be situated on a bed, sofa rug, or similar surface that may block the  
ventilation openings, or placed in a built-in installation, such as a bookcase or cabinet that may impede the  
flow of air through the ventilation openings.  
Heat:  
The appliance should be situated away from heat sources such as radiators, heat registers, stoves, or other  
appliance (including amplifiers) that produce heat.  
Power Source:  
The appliance should be connected to a power supply only of the type described in the operating instructions  
or as marked on the appliance.  
Grounding or Polarization:  
Precautions should be taken so that the grounding or polarization means of an appliance is not defeated.  
Power-Cord Protection:  
Power supply cords should be routed so that they are not likely to be walked on or pinched by items placed  
upon or against them, paying particular attention to cords and plugs, convenience receptacles and the point  
where they exit from the appliance.  
Cleaning:  
The appliance should be cleaned only as recommended by the manufacturer.  
Non-use Periods:  
The power cord of the appliance should be unplugged from the outlet when left unused for a long period of time.  
Object and Liquid Entry:  
Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings.  
Damage Requiring Service:  
The appliance should be serviced by qualified service personnel when:  
- The power supply cord or the plug has been damaged; or  
- Objects have fallen, or liquid has been spilled into the appliance; or  
- The appliance has been exposed to rain; or  
- The appliance does not appear to operate normally or exhibits a marked change in performance; or  
- The appliance has been dropped, or the enclosure damaged.  
Servicing:  
The user should not attempt to service the appliance beyond that is described in the Operating Instructions.All  
other servicing should be referred to qualified service personnel.  
3
Download from Www.Somanuals.com. All Manuals Search And Download.  
FEEDBACK DESTROYER PRO  
Ultra-high performance 2-channel digital Feedback Destroyer / Parametric EQ powered by a 24-bit high-speed DSP  
s 20-bit A/D and D/A converters with 64/128 times oversampling for ultra-high headroom and resolution  
s Automatically and “intelligently” searches out and destroys up to 12 frequencies per channel  
s 24 fully programmable Parametric Filters that can be set manually or via MIDI  
s “Set-and-forget” default setting enables immediate and super-easy Feedback Destroyer performance  
s Single-Shot mode automatically searches and destroys feedback and locks the filter until you reset them  
manually  
s Auto mode continuously monitors the mix, resetting programmed filters automatically  
s Manual mode allows for setting up to 2 x 12 fully parametric filters including Frequency, Bandwidth and  
Gain  
s Single-Shot, Auto and Manual modes are assignable for each filter  
s Free FEEDBACK DESTROYER software allows for total remote control via PC (download at  
www.behringer.de)  
s Two software engines give you independent or coupled functions on left and right channels  
s Internal 24-bit processing with professional 46 kHz sampling rate  
s Servo-balanced Inputs and Outputs on gold-plated XLR and TRS Jack connectors for high signal integrity  
s Full MIDI capability and user preset memories to store programs for instant recall  
s Accurate eight-segment LED level meters simplify level setting for optimum performance  
s “Future-proof” software-upgradeable architecture  
s High-quality components and exceptionally rugged construction ensures long life and durability  
s Internal power supply design for professional applications  
s Manufactured under the ISO9000 management system  
4
Download from Www.Somanuals.com. All Manuals Search And Download.  
FOREWORD  
Dear Customer,  
Welcome to the team of FEEDBACK DESTROYER PRO users and thank you very much for expressing your  
confidence in BEHRINGER products by purchasing this unit.  
It is one of my most pleasant tasks to write this letter to you, because it is the culmination of many months of  
hard work delivered by our engineering team to reach a very ambitious goal: making an outstanding device  
better still. The FEEDBACK DESTROYER has for some time been a standard tool used by numerous studios  
and P.A. rental companies. The task to improve one of our best-selling products certainly meant a great deal  
of responsibility, which we assumed by focusing on you, the discerning user and musician. It also meant a lot  
of work and night shifts to accomplish this goal. But it was fun, too. Developing a product usually brings a lot  
of people together, and what a great feeling it is when everybody who participated in such a project can be  
proud of what we’ve achieved.  
E
It is our philosophy to share our joy with you, because you are the most important member of the BEHRINGER  
family. With your highly competent suggestions for new products you’ve greatly contributed to shaping our  
company and making it successful. In return, we guarantee you uncompromising quality (manufactured under  
ISO9000 certified management system) as well as excellent technical and audio properties at an extremely  
favorable price. All of this will enable you to fully unfold your creativity without being hampered by budget  
constraints.  
We are often asked how we can make it to produce such high-grade devices at such unbelievably low prices.  
The answer is quite simple: it’s you, our customers! Many satisfied customers means large sales volumes  
enabling us to get better conditions of purchase for components, etc. Isn’t it only fair to pass this benefit back  
to you? Because we know that your success is our success, too!  
I would like to thank all people whose help on “Project FEEDBACK DESTROYER PRO“ has made it all  
possible. Everybody has made very personal contributions, starting from the designers of the unit via the many  
staff members in our company to you, the user of BEHRINGER products.  
My friends, it’s been worth the trouble!  
Thank you very much,  
Uli Behringer  
5
Download from Www.Somanuals.com. All Manuals Search And Download.  
TABLE OF CONTENT  
1. INTRODUCTION.....................................................................................................................7  
1.1 The design concept ......................................................................................................................... 7  
1.2 Before you begin ............................................................................................................................. 7  
1.3 Hook up & go .................................................................................................................................. 8  
1.4 Control elements ............................................................................................................................. 9  
1.4.1 Front panel control elements................................................................................................. 9  
1.4.2 Rear panel ........................................................................................................................... 11  
2. OPERATION .......................................................................................................................... 11  
2.1 Activating/deactivating the filters ................................................................................................... 12  
2.2 Manual filters / parametric equalizer .............................................................................................. 12  
2.3 Automatic filters ............................................................................................................................ 12  
2.4 Working with programs ................................................................................................................. 12  
2.4.1 Recalling programs ............................................................................................................. 12  
2.4.2 Choice of mode ................................................................................................................... 13  
2.4.3 Editing filter parameters ...................................................................................................... 13  
2.4.4 Storing programs................................................................................................................. 14  
2.5 MIDI control................................................................................................................................... 14  
3. APPLICATIONS .....................................................................................................................15  
3.1 Level setting.................................................................................................................................. 16  
3.2 Using the FEEDBACK DESTROYER PRO in the monitor path ..................................................... 16  
3.3 Using the FEEDBACK DESTROYER PRO in the main mix bus ................................................... 16  
3.4 Using the FEEDBACK DESTROYER PRO in single channels and sub-groups ............................. 18  
3.5 Using the FEEDBACK DESTROYER PRO in a studio environment .............................................. 18  
3.6 Using the FEEDBACK DESTROYER PRO as an effects device ................................................... 18  
3.7 Special remarks ............................................................................................................................ 19  
3.7.1 Digital overflow .................................................................................................................... 19  
3.7.2 “Tuning in” P.A. and monitor systems.................................................................................. 19  
4. TECHNICAL BACKGROUND ..............................................................................................19  
4.1 Feedback ...................................................................................................................................... 21  
4.2 Graphic equalizers ........................................................................................................................ 22  
4.3 Parametric equalizers ................................................................................................................... 23  
4.4 The FEEDBACK DESTROYER PRO ............................................................................................ 23  
4.5 Digital audio processing ................................................................................................................ 24  
5. INSTALLATION .....................................................................................................................25  
5.1 Rack mounting.............................................................................................................................. 25  
5.2 Mains connection.......................................................................................................................... 25  
5.3 Audio connections ........................................................................................................................ 26  
5.4 MIDI connections .......................................................................................................................... 27  
5.5 Operating level Switch................................................................................................................... 28  
6. APPENDIX .............................................................................................................................28  
6.1 Frequency chart ............................................................................................................................ 28  
6.2 Preset table .................................................................................................................................. 29  
6.3 MIDI implementation ..................................................................................................................... 30  
6.4 Specifications................................................................................................................................ 31  
7. WARRANTY ..........................................................................................................................32  
6
Download from Www.Somanuals.com. All Manuals Search And Download.  
1. INTRODUCTION  
With the FEEDBACK DESTROYER PRO you have purchased a highly useful device for the control of sound  
reinforcement systems, which will enable you to focus your attention on what is essential: your music. The  
fully featured FEEDBACK DESTROYER PRO not only suppresses feedback but also incorporates a wealth of  
additional functions in one single unit. Its 24 separate filters can be edited in all parameters and automatically  
detect and suppress feedback frequencies. With its pro-level internal signal processing circuitry, the unit can  
also be used as a high-end equalizer for stage and studio applications. The MIDI interface allows for integrating  
the FEEDBACK DESTROYER PRO into any MIDI system, and the open system architecture enables you to  
update the system software whenever you want. In short: the BEHRINGER FEEDBACK DESTROYER PRO  
was built for the next millennium.  
E
+
The following operational manual will introduce you to the BEHRINGER  
FEEDBACK DESTROYER PRO and its various functions. After reading the manual carefully,  
make sure it is always on hand for future reference.  
1.1 The design concept  
Despite extensive computing work which is done in the DSP1100P by a “dual-engine” 24-bit processor, the  
FEEDBACK DESTROYER PRO can be operated easily and conveniently. All parameter edits are performed  
with the jog wheel (rotary control). 10 presets are available to store user-defined programs.  
The philosophy behind BEHRINGER products guarantees a no-compromise circuit design and employs the  
best choice of components. Top-quality 20-bit AD/DA converters which belong to the best components avail-  
able owing to its outstanding specifications and excellent sonic characteristics. Two 24-bit DSPs are used as  
the heart of the FEEDBACK DESTROYER PRO. These perform the precise calculations needed for the pro-  
cessing of the complex algorithms. Additionally, the FEEDBACK DESTROYER PRO uses high quality resis-  
tors and capacitors with very tight tolerances, high-grade switches, low-noise operational amplifiers (type  
4580) as well other selected components.  
The FEEDBACK DESTROYER PRO DSP1100P uses SMD technology (Surface Mounted Device). These  
subminiature components known from aerospace technology allow for an extreme packing density, improving  
the unit’s reliability even further. Additionally, the unit is manufactured in compliance with a ISO9000 certified  
management system.  
1.2 Before you begin  
Your BEHRINGER FEEDBACK DESTROYER PRO was carefully packed in the factory and the packaging  
was designed to protect the unit from rough handling. Nevertheless, we recommend that you carefully examine  
the packaging and its contents for any signs of physical damage, which may have occurred in transit.  
+
If the unit is damaged, please do not return it to us, but notify your dealer and the shipping  
company immediately, otherwise claims for damage or replacement may not be granted.  
Shipping claims must be made by the consignee.  
The BEHRINGER FEEDBACK DESTROYER PRO fits into one standard 19" rack unit of space (1 3/4"). Please  
allow at least an additional 4" depth for the connectors on the back panel.  
Be sure that there is enough space around the unit for cooling and please do not place the  
FEEDBACK DESTROYER PRO on high temperature devices such as power amplifiers etc. to avoid overheat-  
ing.  
+
Before you connect your FEEDBACK DESTROYER PRO to the mains, please make sure that  
your local voltage matches the voltage required by the unit! (see chapter 5 for details)  
The mains connection of the FEEDBACK DESTROYER PRO is made by using a mains cable and a standard  
IEC receptacle. It meets all of the international safety certification requirements. Please make sure that all  
units have a proper ground connection.  
+
Please ensure that only qualified persons install and operate the FEEDBACK DESTROYER PRO.  
During installation and operation the user must have sufficient electrical contact to earth.  
1. INTRODUCTION  
7
Download from Www.Somanuals.com. All Manuals Search And Download.  
Electrostatic charges might affect the operation of the FEEDBACK DESTROYER PRO!  
For further information on correct installation see chapter 5 “Installation”.  
As a standard the audio inputs and outputs on the BEHRINGER FEEDBACK DESTROYER PRO are fully  
balanced. If possible, connect the unit to other devices in a balanced configuration to allow for maximum  
interference immunity.  
The automatic servo function detects unbalanced connections and compensates the level difference automati-  
cally (6 dB correction). The MIDI links (IN/OUT/THRU) are made over standardized DIN patch cords. The data  
communication is isolated from ground by opto couplers.  
1.3 Hook up & go  
We know you are anxious to get to work with your new FEEDBACK DESTROYER PRO, the band is probably  
setting up now, you’re half an hour behind schedule, it is hectic, dark and damp. If you promise to read the  
whole manual tomorrow, or at least next week, we show you how to get up and go and get through this night  
alive. If you’ve used a variety of PA gear, you’ll have the FEEDBACK DESTROYER PRO up and running after  
quickly perusing the manual. If you’re not so experienced, don’t worry, it will come to you. In both cases, still  
read the manual! The following may then help you get it happening with a minimum of fuss.  
+
In order to use the full potential of your FEEDBACK DESTROYER PRO, please bear in mind the  
following points:  
1.  
No device will fully compensate for wrong microphone handling! Be aware that there are some actions on  
stage may still result in feedback.  
2.  
3.  
Allow some time for experimentation – you may need to get used to the DSP1100P over several gigs.  
The FEEDBACK DESTROYER PRO’s single shot filters are well suited to automatically attenuate  
resonances which are most likely to cause feedbacks.  
The most probable use for the FEEDBACK DESTROYER PRO is feedback suppression in a stage monitor  
system or in a PA system. The unit should be placed between your console and the poweramplifiers.  
1.  
2.  
3.  
First, connect the unit as seen below.  
Check the operating level switch on the back panel. For most PAs, this should be set to +4 dB.  
On power-up, the Jog Wheel can select any of 10 programs. Programs 1 – 3 give you instant feedback  
suppression for all 12 filters. Choose Program 8 or 10 for stereo processing of the master output.  
+
Note that the Bypass switch can be either Off or On, but NOT flashing! When Bypass is flashing,  
the whole unit is bypassed. But in the other two modes, filters set to Auto or Single Shot will  
still operate.  
P.A. System  
P.A. System  
Monitor System  
Monitor Out  
Master Out  
Master Out  
Fig. 1.1: Monitor application  
Fig.1.2: PA application  
+
If you are using the FEEDBACK DESTROYER PRO for two separate monitor channels the L & R  
Engines should not be coupled.  
8
1. INTRODUCTION  
Download from Www.Somanuals.com. All Manuals Search And Download.  
On start-up; all active filters (AU/SI) are indicated by flashing LEDs. When feedback has been detected and  
dealt with, the LED stops flashing. When all filters are set the oldest automatic filter starts flashing, indicating  
that it will be the next filter to handle new feedback. Parametric filters are also indicated by a non-flashing LED.  
In Single Shot mode the filter will not release a setting which has been achieved until you manually change it.  
This is particularly useful with problems at discrete frequencies like turntable resonances and fixed micro-  
phone and monitor positions. If feedback is detected the filter will deal with that frequency and the status of that  
filter will change to Locked (LO). It will only widen its bandwidth or increase the attenuation but it will not  
release that setting to destroy a new feedback. In Auto mode the oldest filter will be released to destroy a new  
feedback.  
E
1.4 Control elements  
Fig. 1.1: FEEDBACK DESTROYER PRO front panel  
The BEHRINGER FEEDBACK DESTROYER PRO is equipped with ten parameters keys, one jog wheel  
(rotary control) which is used to alter the selected parameter or preset and a numeric LED display. Each of the  
24 filters has one LED assigned to it, which informs you about the status of the filter. By means of an 8-stage  
LED meter each of the two fully independent channels can be monitored.  
1.4.1 Front panel control elements  
Fig. 1.2: Display section DSP1100P  
1
The two LED chains read the output signal level in dB, referenced to the internal digital maximum. If the  
FEEDBACK DESTROYER PRO is set to Total Bypass mode, the level meter displays the input level.  
+
Please note that the nominal level of the FEEDBACK DESTROYER PRO can be selected with  
the +4 dBu / -10 dBV switch located on the back panel.  
2
The FEEDBACK DESTROYER PRO features 24 filters which can be monitored conveniently with the  
indicators next to the display. Twelve LEDs inform you about the status of the filters of each channel  
(left/right). A bright LED announces that a filter has been set. Cyclically flashing LEDs idicate filters that  
are searching in Single-Shot and Auto mode.  
3
4
After power-up, the LED display reads the number of the preset last used. This clearly legible, 2½ digit  
numeric display has plus/minus indicators to show that parameters are being incremented or decremented  
in Edit mode.  
The indicators Hz, kHz, 1/60 and dB to the right of the display light up when you change the associated  
parameters in Edit mode. For example, if you raise the level of a filter, the “dB” indicator lights up. A “+”  
to the left of the preset number signals that the level is being increased.  
1. INTRODUCTION  
9
Download from Www.Somanuals.com. All Manuals Search And Download.  
Fig. 1.3: Function keys and jog wheel  
5
With the JOG WHEEL, a continuous rotary control, you can freely edit the selected parameters. Turn  
the wheel clockwise to increase the values, or counterclockwise to reduce them.  
+
As long as none of the edit functions to the right of the jog wheel has been selected, you can  
use the wheel to select a program directly, which is shown by a dot lighting up in the display.  
While this dot is on, you can select a program though its settings will not take immediate  
effect. When the jog wheel has not been touched for one second, the LED in the display  
disappears and the program is loaded.  
6
7
With FILTER SELECT activated you use the jog wheel to select one of the 12 filters per channel.  
The FILTER MODE key gives you access to the four operating modes: “OF”, Parametric EQ (PA),  
Single-Shot (SI) and Auto Mode (AU). In addition you can edit the threshold of feedback suppression  
(-3 to -9 dB) by pressing the FILTER MODE and the GAIN key together for about 1 seconds.  
11  
12  
Use the ENGINE L key to select the left audio channel.  
Use the ENGINE R key to select the right audio channel. If you wish to process the left and right audio  
channels simultaneously (COUPLE mode), press both ENGINE keys together. In couple mode both  
engine LEDs light up. Whenever you edit one of the two audio channels and then switch to couple mode,  
the parameters of the active channel will be copied to the other; i.e. if you press ENGINE L before  
ENGINE R, left will be copied to right.  
8
9
Use the ENGINE L key to select the left audio channel.  
Use the ENGINE R key to select the right audio channel. If you wish to process the left and right  
channels simultaneously (Couple mode), press both Engine keys at the same time.  
10  
Press the FREQUENCY key to select the frequency you wish to process. The  
FEEDBACK DESTROYER PRO splits up the adjustable frequency range (20Hz to 20 kHz) into the 31  
standard ISO values of a graphic EQ (see 6.1).  
11  
12  
The FINE key allows you to fine tune the standard ISO frequencies (in 1/60-octave steps) within a tuning  
range of 1/3 octave (-9/60 to +10/60).  
BANDWIDTH determines the filter bandwidth of the selected filter. The adjustable value ranges from  
2 octaves (120/60 octave) down to 1/60 octave.  
13  
14  
The GAIN key sets the desired boost/cut of the selected filter in dB (+16 dB / -48 dB).  
The IN/OUT key allows for optional bypassing of the parametric filters or all filters. By shorty pressing  
the IN/OUT key only the parametric filters will be deactivated and the green LED ends up lighting. Hold  
down the IN/OUT key for about two seconds to deactivate all filters. A cyclically flashing LED will  
indicate this Total-Bypass mode. One further pressing reactivates all filters. The LED flickers when  
relevant MIDI data is received.  
+
Please, use the Total-Bypass function only with utmost caution because by deactivation, the  
FEEDBACK DESTROYER PRO possibly unlocks suppressed feedbacks.  
15  
Any modifications made to a preset can be stored with the help of the STORE key. Ten presets are  
available on the FEEDBACK DESTROYER PRO. Press the IN/OUT and the STORE keys, the  
FEEDBACK DESTROYER PRO automatically enters MIDI mode.  
10  
1. INTRODUCTION  
Download from Www.Somanuals.com. All Manuals Search And Download.  
+
Press and keep the keys FILTER SELECT and STORE before powering up the  
FEEDBACK DESTROYER PRO. Then switch on the FEEDBACK DESTROYER PRO and keep the  
two keys pressed for about one second. The program numbers are counted up and reset to  
their original default settings.  
16  
Use the POWER switch to switch the FEEDBACK DESTROYER PRO on or off.  
1.4.2 Rear panel  
E
Fig. 1.4: Rear panel connectors and control elements  
17  
This is the MAINS CONNECTOR / FUSE HOLDER / VOLTAGE SELECTOR. Before you connect the  
unit, please make sure that the displayed voltage corresponds to your Mains supply. Please note that  
the AC voltage selection is defined by the position of the Fuse Holder. If you intend to change the  
operating voltage, remove the Fuse Holder and turn it by 180 degrees before you reinsert it. Matching  
the two markers monitors the selected voltage. Please note that, depending on the mains voltage  
supplied to the unit, the correct fuse type and rate must be installed (see chapter 6.4 “SPECIFICA-  
TIONS”). Please use the enclosed mains cable to connect the unit to the mains power supply. (Please  
note that not all appliances can be used with different mains voltage ratings. Please check the descrip-  
tion on the back of the unit and the box.)  
18  
19  
These are the FEEDBACK DESTROYER PRO’s MIDI connectors (MIDI OUT / THROUGH / IN). Via  
these connectors total remote control is possible.  
Please take the time to make a note of the SERIAL NUMBER in the space provided on the enclosed  
Warranty Registration Card. Put the instruction manual in a safe place and return the completed  
Warranty Registration Card to us within 14 days of purchase, making sure that the dealer stamp  
has been acquired.  
20  
21  
These are the FEEDBACK DESTROYER PRO’s analog OUTPUTS. Also on balanced or unbalanced  
XLR or TRS jacks.  
Use the OPERATING LEVEL switch to adapt the FEEDBACK DESTROYER PRO to different operat-  
ing levels. You can select a -10 dBV semi-pro level used for home recording and a +4 dBu level used  
in professional studios.  
22  
These are the FEEDBACK DESTROYER PRO’s analog INPUTS. The FEEDBACK DESTROYER PRO  
has both XLR and jack inputs and outputs. Each XLR and jack set are wired parallel and can be used  
either balanced and unbalanced.  
2. OPERATION  
The following chapter will familiarize you with the operation of your BEHRINGER  
FEEDBACK DESTROYER PRO. It will provide you with the basic understanding of how to obtain the desired  
results and should encourage you to experiment with the DSP1100P. Please bear in mind that the technical  
specifications of a unit may determine its limits, but the skill of the audio engineer determines how much use  
can be made from it. So do not hesitate to play with the unit, just like a musician does with an instrument, in  
order to explore the full functionality of your FEEDBACK DESTROYER PRO.  
The BEHRINGER FEEDBACK DESTROYER PRO can operate in four different modes. To meet more com-  
plex requirements with regard to flexible signal processing, these modes can be combined in a program.  
2. OPERATION  
11  
Download from Www.Somanuals.com. All Manuals Search And Download.  
2.1 Activating/deactivating the filters  
In “OF” mode, the corresponding filter is deactivated and can be activated by selecting one of the modes  
described below.  
2.2 Manual filters / parametric equalizer  
The FEEDBACK DESTROYER PRO allows you to freely process any music signals. To raise or lower  
specific frequencies in level, you can directly select these frequencies by means of the manual filters (Para-  
metric EQ mode). Each filter has the functionality of a fully parametric EQ, i.e. you can set the center  
frequency, the quality factor (Q) and the amount of boost/cut (in dB).  
2.3 Automatic filters  
The FEEDBACK DESTROYER PROs automatic filters operate in two modes: Single-Shot and Auto mode. In  
order to find a feedback, the FEEDBACK DESTROYER PRO divides the entire frequency band into 1/60  
octave steps (20 Hz to 20 kHz) and determines the respective level of these individual bands. He compares  
this value to the level of the entire signal. The difference of these levels determines whether a filter is set. The  
FEEDBACK DESTROYER PRO now provides you with the unique possibility to adapt this parameter according  
to your own needs. You can edit this feedback sensitivity within a range of -3 dB to -9 dB (in 1 dB steps). The  
standard value for this parameter is -6 dB. This value provides an optimal recognition of feedback during most  
applications. During e.g. a pure speech transmission, the feedback sensitivity can be lowered to -9 dB. In this  
way, the algorithm would recognize and would suppress a feedback even faster. On the other hand a higher  
adjustment of the feedback sensitivity (e.g. -3 dB) makes feedback suppression more stable. In addition to  
that intended feedbacks (guitars or keyboards) become recognized much more slower.  
Filters in Single-Shot mode automatically analyze the music signal to detect feedback frequencies. Having  
detected such a frequency, the filter automatically configures its parameter to suppress feedback as efficiently  
as possible. As the filter is locked to the detected frequency, this mode is ideally suited to suppress feedback  
having a constant frequency. Possible applications are “fixed-position” microphones (e.g. on the drums). After  
the filter has adjusted itself automatically, it enters a special Lock mode, which means that although the  
frequency remains fixed, the width and depth of the filter are still being adapted to the feedback frequency, i.e.  
the width is increased as soon as the feedback frequency begins to shift, and the gain is cut if feedback  
prevails. The gain is not reduced to prevent feedback from recurring.  
All microphones that are moved during a performance (e.g. vocal mics) very often have varying feedback  
frequencies. This type of feedback should be suppressed in Auto mode. As in Single-Shot mode, the filter  
automatically selects an ideal setting for feedback suppression. But in Auto mode a locked filter tracks and  
suppresses the feedback frequency even as it changes. The optimum frequency is selected automatically and  
the filter is set to narrow-band mode so as to influence the music signal as little as possible. If your music  
contains wanted feedback elements (e.g. guitar feedback), it is highly probable that these will be suppressed  
too in Auto mode, because from a physical point of view it is impossible to distinguish “wanted” from “un-  
wanted” feedback. Please read the hints given in section 6.3 to work around this situation.  
2.4 Working with programs  
In order to store your favorite settings, the FEEDBACK DESTROYER PRO has ten user presets and a default  
preset. All operating parameters can be stored, i.e. your programs are recalled in full detail. Owing to state-of-  
the-art circuitry, no internal battery is needed, hence the memory contents will not be lost. In the default preset  
(display “--”), which serves as a basis for creating your own programs, all filters remain in the parametric mode,  
with bandwidth set to 1 octave, a frequency of 500 Hz and 0 dB gain.  
2.4.1 Recalling programs  
After power-up, the FEEDBACK DESTROYER PROs display reads the number of the preset last used. The  
jog wheel allows you to conveniently select the preset of your choice. Turn the rotary control to the left to step  
through the programs in descending order. Turn it to the right to increment the programs. The default preset is  
located in front of the first program.  
+
Please note that the FEEDBACK DESTROYER PRO generally activates the newly selected presets  
12  
2. OPERATION  
Download from Www.Somanuals.com. All Manuals Search And Download.  
only after about one second, which is indicated by a dot in the lower right corner of the display.  
After loading the data, the FEEDBACK DESTROYER PRO enables the preset and the dot  
disappears. This brief interruption avoids the direct activation of every preset, as you scroll  
through the preset list with the jog wheel. Thus, the FEEDBACK DESTROYER PRO makes sure  
that no "unwanted" programs are loaded unintentionally. Additionally, you can rotate the jog  
wheel at high speed and still have the time to specifically select the preset of your choice,  
instead of any of its "neighbors".  
2.4.2 Choice of mode  
E
Each filter mode has two letters assigned to it, who appears in the display after pressing the FILTER MODE  
key. The following display messages can be recognized:  
Display Mode of operation  
OF  
PA  
AU  
SI  
Off  
Parametric EQ  
Auto  
Single Shot  
Locked (S)  
LO  
Tab. 2.1: FEEDBACK DESTROYER PRO operating modes  
To change the filter mode, you first have to press the FILTER SELECT key to specify the number of the filter (1  
to 12) with the jog wheel. Using the ENGINE keys you can not only select the left or right channel, but also  
both ones at the same time. Then you can choose the filter mode by simply pressing the FILTER MODE key  
and turning the jog wheel. The display message “L” (locked) informs you that a filter from the Single-Shot mode  
is already suppressing a feedback. You can unlock such a filter by switching it back to single mode. As soon  
as a new feedback will be found, the FEEDBACK DESTROYER PRO switches the filter from the old frequency  
to the new one. If you leave the Auto or Single-Shot mode and enter the Parametric mode, the filter keeps all  
parameter settings.  
In order to avoid an inadvertent change, the filter mode selection takes place after a period of approximately one  
second. This is indicated by a dot in the lower right corner of the display.  
By pressing and keeping the FILTER MODE and the GAIN key for about 2 seconds you can adjust the  
feedback threshold within a range of -3 dB to -9 dB.  
2.4.3 Editing filter parameters  
To change filter settings, the filter has to situate in Parametric EQ mode. In this case you can adapt the center  
frequency by pressing the FREQUENCY key. Depending on the frequency, either the “Hz” or “kHz” indicator to  
the right of the display lights up. If you want to lift the frequency to e.g. 2700 Hz turn the jog wheel until the ISO  
frequency (2.5 kHz, see table 6.1 standard ISO frequencies) closest to this value appears in the display and  
the “kHz” indicator lights up. The FINE key allows you to fine tune the chosen standard ISO frequency within  
a tuning range of 1/3 octave (in 1/60-octave steps). The mathematical proportion between the displayed value  
and the absolute frequency, and an easy guide to quickly find the desired frequency is available in chapter 7  
(frequency chart). The bandwidth of the filter can be adjusted by selecting the BANDWIDTH key. The adjust-  
able bandwidth ranges from 2 octaves down to 1/60 octave. By pressing the GAIN key it is possible to set the  
desired boost or cut of the selected frequency. A “+” signals that the level is being increased and a “-” signals  
a decreasement.  
In Single-Shot and Auto mode it is not possible to change the filter parameters. In these modes you only are  
allowed to call up the parameters. However you can convert such a filter into a parametric one with same  
frequency, and bandwidth, but with a gain of 0 dB. You simply have to press and keep the FILTER MODE key  
for about 2 seconds. To reactivate a locked filter simply choose the Single-Shot or Auto mode.  
2. OPERATION  
13  
Download from Www.Somanuals.com. All Manuals Search And Download.  
2.4.4 Storing programs  
Use the STORE key to store the program. Basically, all parameter changes in Parametric EQ mode can be  
saved. Filters working in Single-Shot or Auto mode will adjust and store the required parameters automatically.  
Example:  
s
You recall a program for editing. Then you edit the preset as desired using the function keys and the jog  
wheel. During this process, the flashing STORE key reminds you that the preset settings have been  
changed but not saved yet. Press the STORE key once. The display reads the current preset number and  
starts flashing. To keep the original preset, use the jog wheel to select a different preset that can be  
overwritten. Press the STORE key again to save the edits to the selected preset. If you wish to overwrite the  
original preset, simply press the STORE key twice (after editing) to save all changes you have made.  
+
Whenever you have edited a preset and pressed the STORE key twice, all previous settings in  
this preset are erased and overwritten with the new parameter values. However, if you wish to  
keep the original preset, use the jog wheel to select another preset before you press the  
STORE key a second time.  
2.5 MIDI control  
Use the MIDI key combination to select the MIDI parameters you wish to adjust. For this purpose press and  
keep the IN/OUT and the STORE keys for about two seconds. All parameters can be edited with the jog wheel  
and the IN/OUT key. The MIDI menu includes six pages which you can select by pressing the IN/OUT key  
(forwards) and the STORE key (backwards) several times.  
On the first page you can select the MIDI channel. The display reads a small “c” (= channel). The jog wheel  
adjusts a channel from 1 through 16. To switch off the MIDI function simply select the “0” value (displayed as  
“-”).  
On the second page you can select MIDI Omni mode, i.e. the unit transmits/receives on all 16 MIDI channels.  
The display reads “O” (=Omni). Use the jog wheel to activate (“1”) or deactivate (“0”) Omni mode.  
The third page allows for configuring controller commands. On its right-hand side, the display reads a capital  
“C” (=Controller). The jog wheel selects one of the following four controller modes:  
Display  
Mode  
0
1
2
3
4
No controller data are transmitted  
Controller data are received but not transmitted  
Controller data are transmitted but not received  
Controller data are transmitted and received  
As 3, with additionally the automatic filter parameters  
Tab. 2.2: Controller settings  
+
When you choose value “4” the FEEDBACK DESTROYER PRO will also send the settings of the  
automatic filters.  
The fourth page gives you access to the program change setup. The display reads a capital “P” (=Program).  
Here, too, four modes can be selected with the jog wheel, as follows:  
Display  
Mode  
0
1
2
3
No program change data are transmitted  
Program change data are received but not transmitted  
Program change data are transmitted but not received  
Program change data are transmitted and received  
Tab. 2.3: Program change settings  
The fifth page of the MIDI menu shows the “store enable“ flag represented by a capital “S” in the display. The  
value “0” disables the reception of controller #18, and therefore protects the user presets from being modified  
14  
2. OPERATION  
Download from Www.Somanuals.com. All Manuals Search And Download.  
via MIDI. Accordingly, the value “1” enables MIDI controller #18 so that you can modify or replace presets  
with a remote MIDI device or a sequencer. In this case the actual settings will be stored directly to the location  
that corresponds to the controller value.  
+
Attention! Since the “store enable“ mode allows you to access memory locations directly via  
MIDI, it is possible that stored presets will be replaced or altered if controller #18 messages are  
sent on the same MIDI channel. The purpose of this mode is to facilitate MIDI backup and  
restore operations without express confirmation at the FEEDBACK DESTROYER PRO. It is  
therefore recommended to disable (flag=0) this mode as soon as the intended data transfer  
has ended. This is done automatically when you switch off the FEEDBACK DESTROYER PRO.  
E
On the sixth, and presently the last, page you can access the ”System Exclusive” functions. This is indicated  
by a ”d” (for dump) in the display. To the left of this ”d” a number is displayed:  
- 0 means that no SYSEX data will be sent or accepted.  
- 1 will enable the FEEDBACK DESTROYER PRO to receive data. When STORE is pressed the unit will wait  
for data, this  
is shown by flashing dots (LEDs) in the display. The MIDI button LED flashes signaling that SYSEX data is  
being received.  
- 2 will enable the FEEDBACK DESTROYER PRO to send a ”bulk dump”. Start your sequencer and press  
STORE on the unit to start the transmission.  
If you press the IN/OUT key again on the fifth page, the FEEDBACK DESTROYER PRO quits MIDI setup  
mode.  
To load these settings again, select 1, press STORE and start your sequencer. If you press IN/OUT again, you  
will leave the MIDI setup. You can at all times press any other key to leave the MIDI setup directly.  
+
During a bulk dump all audio functions of the FEEDBACK DESTROYER PRO will be deactivated.  
The full-featured MIDI implementation of the FEEDBACK DESTROYER PRO allows for easily integrating the  
FEEDBACK DESTROYER PRO into any MIDI system.  
s MIDI IN  
Any MIDI data sent to the FEEDBACK DESTROYER PRO (sequencer, MIDI footswitch, etc.) are received via  
the MIDI IN jack. For example, if you wish to use the FEEDBACK DESTROYER PRO as an effects device for  
your guitar rack, you can connect the MIDI IN jack to a MIDI footswitch that allows for selecting program  
presets. If your rack includes another MIDI effects device (e.g. a multi-effects processor), the data sent from  
the MIDI footswitch can be routed via the FEEDBACK DESTROYER PROs MIDI THRU jack to your multi-  
effects processor.  
s MIDI THRU  
The MIDI THRU jack is used to loop through incoming MIDI data, i.e. any control data received at the MIDI IN  
of the FEEDBACK DESTROYER PRO will be transmitted via the MIDI THRU jack to other MIDI devices/  
instruments.  
s MIDI OUT  
The MIDI OUT jack allows for transmitting MIDI data that originate from the FEEDBACK DESTROYER PRO.  
We are currently developing a software editor which will allow for storing single items of the  
FEEDBACK DESTROYER PRO`s internal data on an external medium. Thus, it will be possible to archive  
FEEDBACK DESTROYER PRO settings and presets on a computer, sequencer or MIDI data recorder. Both  
MIDI Control Change and MIDI Program Change commands will be transmitted when you edit or recall filter  
settings. Detailed information on this future software editor are available from our BEHRINGER hotline  
(tel. +49 (0) 2154-920666), our international distributors and/or our Internet homepage http://www.behringer.de.  
3. APPLICATIONS  
The BEHRINGER FEEDBACK DESTROYER PRO features a high level of flexibility not only in the field of  
feedback elimination. The following chapter describes some other possible applications for your  
FEEDBACK DESTROYER PRO.  
3. APPLICATIONS  
15  
Download from Www.Somanuals.com. All Manuals Search And Download.  
3.1 Level setting  
Take care to set levels properly on the FEEDBACK DESTROYER PRO! Low levels deteriorate the dynamics  
of the music signal, which results in a poor, weak and noisy sound. On the other hand, excess levels overdriving  
the converters in the FEEDBACK DESTROYER PRO should also be avoided. Digital distortion is (unlike its  
analog counterpart) very unpleasant to hear as it does not occur gradually but abruptly.  
Use the input level meter of the FEEDBACK DESTROYER PRO to adjust the input signal so that the Clip LED  
flickers only rarely. Make sure that it never lights up all the time!  
3.2 Using the FEEDBACK DESTROYER PRO in the monitor path  
Inserting the FEEDBACK DESTROYER PRO into the monitor path of your mixing console gives you maximum  
protection against annoying feedback. Monitor systems are particularly susceptible to feedback because on  
stage there are usually lots of microphones and speakers located in close proximity to each other. Vocal mics  
are especially critical in this context as their levels must be relatively high to be able to “compete” with other  
instruments. Additionally, vocal mics are not always used at fixed positions. It has therefore proven useful to  
protect the monitor paths against feedback. An agreeable side effect when using the  
FEEDBACK DESTROYER PRO in the monitor path is the positive influence on both sound and loudness of  
the monitors, because filtering interference makes the monitor sound more transparent and feedback suppression  
enables you to increase the volume level of the monitors (which is usually highly welcomed by the musicians  
performing on stage).  
P.A. System  
Monitor System  
Monitor Out  
Master Out  
Fig. 3.1: Using the FEEDBACK DESTROYER PRO in the monitor path  
3.3 Using the FEEDBACK DESTROYER PRO in the main mix bus  
The FEEDBACK DESTROYER PRO can also be used to process main mix signals. Please consider the  
following remarks:  
Using the FEEDBACK DESTROYER PRO in the main mix bus gives you the advantage that any feedback  
occurring in the individual microphone channels can be eliminated with just one FEEDBACK DESTROYER PRO.  
However, this also means that “wanted” feedback (e.g. guitar feedback) will be suppressed, too. Furthermore,  
the FEEDBACK DESTROYER PRO could cause a slight manipulation of the main mix sound in extreme  
16  
3. APPLICATIONS  
Download from Www.Somanuals.com. All Manuals Search And Download.  
situations.  
Before applying the FEEDBACK DESTROYER PRO, it is therefore advisable to remove the condition causing  
the feedback problems. For example, try different microphone positions! Use the FEEDBACK DESTROYER PRO  
in the monitor path and in single channels with critical signals. If there is no other way to eliminate feedback,  
you can insert the FEEDBACK DESTROYER PRO into the main mix bus. Unless your mixing console has  
dedicated insert points for the main mix bus, you can simply connect the FEEDBACK DESTROYER PRO  
between mixing console and power amp. If required, adapt the levels with the Operating Level switch.  
Wire the unit as shown below:  
E
P.A. System  
Master Out  
Fig. 3.2: Using the FEEDBACK DESTROYER PRO in the main mix bus  
3. APPLICATIONS  
17  
Download from Www.Somanuals.com. All Manuals Search And Download.  
3.4 Using the FEEDBACK DESTROYER PRO in single channels and sub-groups  
P.A. System  
Sub-Group  
Insert  
Channel  
Insert  
Master Out  
Fig. 3.3: Inserting the FEEDBACK DESTROYER PRO in single channels and sub-groups  
If you want to make sure that deliberately produced feedback signals, such as “guitar feedback”, are not  
eliminated, you should try inserting one or several FEEDBACK DESTROYER PRO`s into single channels (e.g.  
vocal mics) which are susceptible to feedback. Or, you could use the sub-groups of your mixing console by  
routing any channels susceptible to feedback (e.g. all vocal mics) to one or several sub-groups. Thus, all less  
critical signals (e.g. line signals, lower-level instrumental microphones) can pass through the mixing console  
unaltered, while only the critical microphone channels are monitored from the FEEDBACK DESTROYER PRO.  
In this way, you can protect your P.A. system against feedback and still use “wanted” feedback signals.  
3.5 Using the FEEDBACK DESTROYER PRO in a studio environment  
With its highly flexible configuration the FEEDBACK DESTROYER PRO also delivers good results in a profes-  
sional studio or home recording environment, as it provides a maximum of twelve fully parametric equalizers  
per channel in Parametric EQ mode. Thus, you can realize any application ranging from slight processing to  
the total manipulation of music signals. For example, you can use the FEEDBACK DESTROYER PRO as an  
equalizer for your studio monitors or to enhance the EQ’s in your mixing console, as these are often only semi-  
parametric.  
3.6 Using the FEEDBACK DESTROYER PRO as an effects device  
With its MIDI interface the FEEDBACK DESTROYER PRO can also be used as a programmable EQ - as a  
control unit in a guitar rack or in combination with a keyboard. If you own a MIDI footswitch with an expression  
pedal, you can produce interesting wah-wah effects by modifying the filter frequency with the expression pedal  
while playing. A similar effect is produced when the FEEDBACK DESTROYER PRO is used to generate  
“sweeping” sounds. Emphasize or de-emphasize a particular frequency and change the filter frequency con-  
tinuously via MIDI. The resulting effect sound like a heavily modulating phaser (although the phasing effect is a  
different phenomenon from a physical point of view). The advantage in this application is that the sweeping  
sound is MIDI-controllable and can be synchronized to, for instance, a sequencer. This effect is very popular in  
dance and techno music.  
18  
3. APPLICATIONS  
Download from Www.Somanuals.com. All Manuals Search And Download.  
3.7 Special remarks  
3.7.1 Digital overflow  
When using the FEEDBACK DESTROYER PRO as a parametric equalizer (Parametric EQ mode) and  
applying extreme attenuation values in the low end range of the frequency spectrum (below 50 Hz), you  
should perhaps set several filters to process the same frequency. Depending on the amount of attenuation  
applied, the use of only one filter may lead to slight distortion, which produces interference in the signal path.  
This is a natural physical phenomenon which should be avoided. Use for example two filters adjusted to a  
signal attenuation of about -12 dB (with the same frequency and bandwidth). This produces the same effect  
achieved with one filter set to -24 dB.  
E
3.7.2 “Tuning in” P.A. and monitor systems  
With the FEEDBACK DESTROYER PRO you can improve the protection against feedback even before the  
show begins, by “tuning in” your sound reinforcement system: after the system has been set up completely,  
open all microphone channels and activate Single-Shot mode on your FEEDBACK DESTROYER PRO. Then,  
slowly move up the monitor and master faders until feedback comes in. Without the  
FEEDBACK DESTROYER PRO you could not increase the volume level of your system any further. With your  
FEEDBACK DESTROYER PRO, however, you can considerably enhance the system headroom! Move the  
faders further up, and the first feedback signal will be suppressed by the FEEDBACK DESTROYER PRO.  
Continue to move up the faders until about three or four filters are suppressing various feedback signals.  
Subsequently, cut back the volume to the level required for the show. In this way, you can be sure that there is  
enough system headroom should it be necessary to raise the volume level during the concert.  
If you have more than one FEEDBACK DESTROYER PRO for the monitor path, you should use these devices  
to protect critical signal paths. Experience has shown that musicians want to have the volume of their instru-  
ment increased on the monitor as the concert goes on. With the FEEDBACK DESTROYER PRO you can turn  
up the volume without having to fear feedback problems. When the show begins you should set several filters  
to Auto mode in order to suppress feedback produced by “moving” (vocal) microphones. In Auto mode, the  
FEEDBACK DESTROYER PRO automatically tracks and suppresses feedback signals with varying frequen-  
cies.  
4. TECHNICAL BACKGROUND  
The steady development of modern sound reinforcement systems has made it possible to produce almost any  
level of loudness. Yet, the increase in loudness goes in line with a need for optimized audio quality. Today,  
audiences expect to hear a powerful and transparent sound. Nothing can spoil a live event more than interfer-  
ence and feedback.  
High volume levels and the use of ever sophisticated monitor systems with a great number of speaker boxes  
have increased the potential risk of feedback loops. Up to now sound engineers have used conventional 1/3-  
octave equalizers to suppress unwanted feedback. Now, the BEHRINGER FEEDBACK DESTROYER PRO  
gives you the option to delegate this task to the FEEDBACK DESTROYER PRO, so that you can pay your  
music your undivided attention instead of having to suppress feedback with graphic EQ’s using a trial-and-error  
approach.  
To fully understand how the BEHRINGER FEEDBACK DESTROYER PRO works you will need to know the  
meaning of a few fundamental terms used in signal equalization, such as:  
s dB, decibel  
s bandwidth / quality factor (Q)  
s octave, 1/3-octave  
With the FEEDBACK DESTROYER PRO, as with any other type of equalizer, the amount of boost/attenuation  
applied to a specific frequency is expressed in decibels (dB). What’s a decibel? The abbreviation dB is not a  
unit (although often used as one), but describes a logarithmic proportion. The entire dynamic range of human  
hearing (from the threshold of audibility to a jet-airplane, see fig. 4.1) starts with about 0.00002 Pa (threshold of  
audibility) and goes up to 113 Pa (threshold of pain).  
4. TECHNICAL BACKGROUND  
19  
Download from Www.Somanuals.com. All Manuals Search And Download.  
The range of sound pressure levels or the dynamic range of human hearing encompasses a factor of  
10,000,000. This enormous range of values is difficult to handle and additionally does not represent the  
subjective perception of sound, since human hearing tends to use a logarithmic curve. When an increase in  
loudness by the factor two is perceived as one step, four times the loudness level equals two steps. So, the  
decibel is a unit of measurement that describes a level in relation to a reference quantity. To make clear  
which reference quantity is meant, the abbreviation SPL (sound pressure level) is sometimes used together  
with dB. Starting with a value of 0 dB SPL (= 2*10-5 Pa) for the threshold of audibility, any dB values can be  
calculated by means of the following formula:  
p 2  
L
20 log  
=
⋅
p1  
L = e.g. the absolute sound pressure level in dB SPL  
p1 = e.g. a reference sound pressure of 0.00002 Pa  
p2 = the sound pressure (in Pa) produced by the sound source to be calculated  
log = decimal logarithm.  
160  
Jet Engine  
140  
120  
100  
80  
Threshold Of Pain  
Power Drill  
Machinery Hall  
"Loud" Office  
60  
Normal Conversation  
40  
Quiet Apartment  
Recording Studio  
20  
Falling Leaves  
0
Threshold Of Audibility  
Fig. 4.1: Dynamic range of human hearing  
As can be seen, human hearing has a very wide dynamic range of about 130 dB, which surpasses the range  
of a DAT or CD player with an approximate range of 96 dB. From a physical point of view, a 3 dB boost  
corresponds to an increase in power by the factor 2. However, the human ear perceives a signal to be twice as  
loud as before only if it is boosted by about 10 dB. This will give you an idea of the range of boost or attenuation  
that can be realized with the 24 filters of the FEEDBACK DESTROYER PRO. For each filter, you can apply a  
boost of +16 dB or a cut of -48 dB, i.e. you can boost the selected frequency by the subjectively perceived  
factor 3 (physically ≈ 40) or attenuate it by the factor 27 (physically ≈ 60,000)!  
The sound which an EQ produces not only depends on the selected frequency and the amount of gain (ex-  
pressed in dB); the bandwidth of the filters also plays an important role. Here, we generally use the so-called  
absolute bandwidth of a filter, which is measured from the lower to the upper cutoff frequency. Starting from  
there, you can divide the absolute bandwidth by the filter’s center frequency to calculate the relative bandwidth.  
The quality factor (Q) is simply the reciprocal value of the relative bandwidth.  
20  
4. TECHNICAL BACKGROUND  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Filter attenuated by 8 dB at 1kHz  
Bandwidth = 600 Hz  
0 dB  
-2 dB  
-4 dB  
-6 dB  
-3 dB  
E
-8 dB  
Center frequency  
= 1 kHz  
-10 dB  
-12 dB  
200 Hz  
1 kHz  
5 kHz  
Fig. 4.2: Typical equalizer filter curve  
The filter bandwidth can also be expressed in octaves (as on the FEEDBACK DESTROYER PRO). The  
following table shows a list of decimal Q values vs. octaves:  
Octave  
1/6  
1/4  
1/3  
1/2  
3/4  
1
Quality factor (Q)  
8.65  
5.76  
4.32  
2.87  
1.90  
1.41  
0.92  
0.67  
0.40  
3/2  
2
3
Tab. 4.1: Octaves vs. Q factors  
Now the following relationship becomes clear: the higher the Q factor, the narrower the frequency band that can  
be cut or boosted. On the BEHRINGER FEEDBACK DESTROYER PRO you can adjust the relative bandwidth  
conveniently with the infinitely variable jog wheel. The filter bandwidth can be tuned from 2 octaves (120/60  
octaves) down to 1/60 octave (for fine adjustments).  
4.1 Feedback  
Almost every concert goer may have experienced the howling and squealing of an improperly set sound  
reinforcement system. Feedback is one of the main problems encountered during live events. A feedback loop  
is produced when a microphone signal is reproduced by an amplifier system, to be picked up again (with the  
same phase) by the microphone. Thus, feedback is built up at all frequencies where the distance between  
microphone and speaker corresponds to a multiple of the signal’s wavelength.  
4. TECHNICAL BACKGROUND  
21  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Speaker Box  
Microphone  
Power Amp  
Mixing Console  
Fig. 4.3: Typical feedback loop  
Basically, any microphone signal passing through an amplifier is liable to generate feedback. Unfortunately,  
the feedback frequencies of P.A. systems differ, and even one single system can have varying feedback  
frequencies, as these depend largely on the room acoustics. Feedback can be caused by the following condi-  
tions:  
s The microphones are too close to the speaker boxes or the speakers are badly positioned (monitor sys-  
tem).  
s The microphone channels on the mixing console are not set up correctly.  
s The microphones used are not operated in accordance with their directivity (e.g. cardioid/super-cardioid).  
s The acoustic properties of the room are unfavorable. Tiled walls and floors heavily reflect the sound.  
All rooms feature a number of natural resonances sometimes with “high” quality factor. At such frequencies the  
potential risk of feedback is increased. In addition to the acoustic properties of the room, the relative position  
of the microphone with reference to the loudspeaker plays a decisive role for the generation of feedback. In  
practice, this phenomenon can be observed with microphone held directly in front of a speaker, thus producing  
feedback. Of course, the first thing to do in such a case is to move the microphone away from the speaker.  
When doing so, you can hear the feedback frequency change, because a variation in the distance between  
microphone and loudspeaker results in a variation of feedback frequencies. It is therefore very difficult to  
anticipate feedback frequencies and avoid their occurrence by means of equalizers with fixed settings.  
4.2 Graphic equalizers  
Graphic equalizers are part of the audio engineer’s standard equipment for live applications. In this context,  
graphic EQ’s usually perform three main tasks:  
s Fine tuning the mix to your taste and the style of music.  
s Fine tuning the mix to the room and speaker acoustics.  
s To some extent, audio engineers can use graphic EQ’s to manually suppress annoying feedback.  
The 1/3-octave design with 31 faders per channel has become the standard among graphic equalizers. Here,  
the spacing between individual filter frequencies is 1/3 octave. The quality factor (Q) of the filters (usually 1/3  
octave) is fixed as are the frequencies controlled with the 31 filters.  
1/3-octave equalizers are very popular (e.g. our ULTRA-CURVE PRO DSP8024) because they are so easy to  
operate. The fader positions clearly show how the signal is being processed, especially since graphic EQ’s  
have fixed frequencies based on the so-called ISO standard. So, all graphic equalizers designed to meet the  
ISO standard feature the same fixed frequencies. Once you’ve got used to work with a 1/3-octave equalizer,  
you will find the FEEDBACK DESTROYER PRO a highly convenient tool, as it splits up the audio spectrum  
into the ISO frequencies (see table 1.2), which enables you to access the most important frequencies quickly.  
22  
4. TECHNICAL BACKGROUND  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Of course, you can use the FINE button to fine tune to frequencies between the standard ISO frequencies (in  
1/60-octave steps) within a range of 1/3 octave.  
20 25 31,5 40 50 63 80 100 125 160 200 250 315 400 500 630 800  
1,25 1,6 2,5 3,15 6,3 10 12,5 16 20  
Hz  
kHz  
1
2
4
5
8
Tab. 4.2: standard ISO frequencies  
E
4.3 Parametric equalizers  
Parametric equalizers, unlike graphic EQ’s, allow for selecting both the processing frequency and the band-  
width, so that it is possible to process any given signal in full detail. Naturally, this equalizer design can also  
be used to “filter” unwanted signals, however, only if these signal have a fixed frequency. If the frequency  
changes, the parametric equalizer would have to be readjusted all the time. The majority of (analog) parametric  
EQ’s suffers from a quite fundamental drawback: they are operated by means of rotary controls, i.e. contrary  
to graphic EQ’s, it is much more difficult to make necessary readjustments quickly.  
4.4 The FEEDBACK DESTROYER PRO  
As you have seen, suppressing feedback with a standard graphic and/or parametric equalizer often means that  
you have to accept compromises. Since feedback signals fail to comply with the standard ISO frequencies of  
graphic EQ’s and additionally can have changing frequencies, their suppression with a graphic equalizer is  
more or less a matter of luck.  
Example: let’s assume a feedback signal at 1.8 kHz is produced during a concert. To suppress it, you’ve got  
to cut the 1.8 kHz band on your EQ. However, since graphic equalizers only have 1.6 and 2 kHz bands, you  
might need to attenuate both bands. Result: although feedback will be eliminated due to the low filter quality,  
you will also fade out many music signals which you’d actually wish to keep. Additionally, cutting these  
midrange frequencies also means that your P.A. system loses power and performance.  
In theory, a parametric EQ can be used to suppress feedback by means of high filter qualities. However, your  
tweeters may well have gone up in smoke before you’ve found the frequency at which feedback occurs and  
managed to eliminate it by adjusting the filter frequency, bandwidth and gain accordingly. For this reason, the  
FEEDBACK DESTROYER PRO also uses a highly optimized version of the automated, fully parametric filters  
we designed for the BEHRINGER ULTRA-CURVE. With the FEEDBACK DESTROYER PRO your P.A. sys-  
tem will be under your control again!  
Unlike many conventional equalizers, the FEEDBACK DESTROYER PRO provides an impressive range of  
features:  
s If required, the FEEDBACK DESTROYER PRO detects and suppresses feedback automatically by ana-  
lyzing the music signal and determining the frequency of the interference signal. Additionally, it calculates  
the filter quality and attenuation necessary to fade out feedback.  
s The FEEDBACK DESTROYER PRO calculates the filter quality with such a high precision that nothing but  
the feedback signal will be filtered, while retaining the original music signal. This means increased P.A.  
headroom and a more balanced, powerful and transparent sound image.  
s With the FEEDBACK DESTROYER PRO almost all of the power delivered by the amps will reach the  
speakers, because the precisely set, narrow-band filters reduce energy losses to a minimum.  
s The filters can be operated both in manual and automatic mode. Naturally, you can combine both modes in  
single programs.  
s Clearly structured entry keys give you direct access to essential parameters, while the jog wheel allows  
you to conveniently adjust them as desired. Favorite settings can be stored in 10 preset programs. Of  
course, the FEEDBACK DESTROYER PRO fully integrates into any MIDI system.  
s This enormous processing power is provided by a “software-separated” 24-bit Dual-Engine processor. The  
FEEDBACK DESTROYER PRO precisely converts your music with 20-bit AD/DA converters using a pro-  
level sampling rate of 46 kHz. The high-grade components and circuitry make sure that the quality of the 24  
fully parametric EQ’s meets studio standards.  
4. TECHNICAL BACKGROUND  
23  
Download from Www.Somanuals.com. All Manuals Search And Download.  
s Quick filter settings can be realized by using standard ISO values for the allocation of frequency bands.  
Subsequently, you can fine tune the frequency of your choice.  
4.5 Digital audio processing  
In order to convert an analog signal - e.g. music - into a series of digital words, a so-called “Analogue to Digital  
Converter” or ADC is used. The converter functions by viewing the signal entering it a given number of times  
over a period of time, e.g. 44,100 times per second, giving a rate of 44.1 kHz, and in each case measuring the  
signal amplitude, and giving it a numerical value. This form of measuring the signal regularly over a period of  
time is known as “sampling”, the conversion of the amplitude into a numerical value, quantizing. The two  
actions together are referred to as digitizing.  
In order to carry out the opposite - the conversion of a digitized signal into its original analogue form - a “Digital  
to Analogue Converter” or DAC is used. In both cases the frequency at which the device operates is called the  
sampling rate. The sampling rate determines the effective audio frequency range. The sampling rate must  
always be more than twice the value of the highest frequency to be reproduced. Therefore, the well known CD  
sampling rate of 44.1 kHz is slightly higher than twice the highest audible frequency of 20 kHz. The accuracy  
at which quantization takes place is primarily dependent on the quality of the ADCs and DACs being used.  
The resolution, or size of digital word used (expressed in bits), determines the theoretical Signal/Noise ratio (S/  
N ratio) the audio system is capable of providing. The number of bits may be compared to the number of  
decimal places used in a calculation - the greater the number of places, the more accurate the end result.  
Theoretically, each extra bit of resolution should result in the S/N ratio increasing by 6 dB. Unfortunately, there  
are a considerable number of other factors to be taken into account, which hinder the achievement of these  
theoretical values.  
If you picture an analog signal as a sinusoidal curve, then the sampling procedure may be thought of as a grid  
superimposed on the curve. The higher the sampling rate (and the higher the number of bits), the finer the grid.  
The analog signal traces a continuous curve, which very seldom coincides with the cross points of the grid. A  
signal level at the sampling points will still be assigned a digital value, usually the one closest to the exact  
representation. This limit to the resolution of the grid gives rise to errors, and these errors are the cause of  
quantizing noise. Unfortunately, quantizing noise has the characteristic of being much more noticeable and  
unpleasant to the ear than “natural” analog noise.  
In a digital signal processor, such as the DSPs in the FEEDBACK DESTROYER PRO, the data will be  
modified in a number of ways, in other words, various calculations, or processes, will be done in order to  
achieve the desired effect on the signal. This gives rise to further errors, as these calculations are approxima-  
tions, due to their being rounded off to a defined number of decimal places. This causes further noise. To  
minimize these rounding off errors, the calculations must be carried out with a higher resolution than that of the  
digital audio data being processed (as a comparison, an electronic calculator may operate internally with a  
greater number of decimal places than can be shown on its display). The DSPs in the  
FEEDBACK DESTROYER PRO operate with a 24 bit resolution. This is accurate enough to reduce quantizing  
noise to levels which are usually below the audible threshold. However, when using extreme equalizer settings,  
some quantizing side effects may be detected.  
Digital sampling has one further, very disturbing effect: it is very sensitive to signal overload. Take the following  
simple example using a sine wave. If an analog signal starts to overload, it results in the amplitude of the signal  
reaching a maximum level, and the peaks of the wave starting to get compressed, or flattened. The greater the  
proportion of the wave being flattened, the more harmonics, audible as distortion, will be heard. This is a  
gradual process, the level of distortion as a percentage of the total signal rising with the increase of the input  
signal level.  
24  
4. TECHNICAL BACKGROUND  
Download from Www.Somanuals.com. All Manuals Search And Download.  
U (Voltage)  
Quantization Steps  
Continuous  
Analog Signal  
8
7
0111  
0110  
6
5
4
3
0101  
0100  
0011  
0010  
0001  
0000  
1111  
t (Time)  
E
-8 -7 -6  
-5 -4 -3  
-2  
1
2
3
4
5
6
7
8
-1  
-2  
-3  
1110  
1101  
Quantization Errors  
(Noise)  
1100  
-4  
-5  
-6  
-7  
1011  
1010  
1001  
1000  
-8  
Conversation Rate  
Digital Words  
Fig. 4.4: Transfer diagram for an ideal linear ADC (2’s complement representation)  
Digital distortion is quite different, as illustrated by this simplified example. If we take the situation where a 4  
bit word has the positive maximum value of 0111, and add to it the smallest possible value of 0001 (in other  
words, the smallest increase in amplitude possible), the addition of the two results in 1000 - the value of the  
“negative” maximum. The value is turned on its head, going instantly from positive max to negative max,  
resulting in the very noticeable onset of extreme signal distortion.  
5. INSTALLATION  
Your BEHRINGER FEEDBACK DESTROYER PRO was carefully packed in the factory and the packaging  
was designed to protect the unit from rough handling. Nevertheless, we recommend that you carefully examine  
the packaging and its contents for any signs of physical damage, which may have occurred in transit.  
+
If the unit is damaged, please do not return it to us, but notify your dealer and the shipping  
company immediately, otherwise claims for damage or replacement may not be granted.  
Shipping claims must be made by the consignee.  
5.1 Rack mounting  
The BEHRINGER FEEDBACK DESTROYER PRO fits into one standard 19" rack unit of space (1 3/4"). Please  
allow at least an additional 4" depth for the connectors on the back panel. Be sure that there is enough air  
space around the unit for cooling and please do not place the FEEDBACK DESTROYER PRO on high tem-  
perature devices such as power amplifiers etc. to avoid overheating.  
5.2 Mains connection  
The mains connection of the FEEDBACK DESTROYER PRO is made by using a mains cable and a standard  
IEC receptacle. It meets all of the international safety certification requirements.  
+
Please make sure that all units have a proper ground connection. For your own safety, do not  
remove the ground connection within the units or at the supply, or fail to make this connection  
at all.  
Before you switch on the unit, check that it is configured to match your AC mains voltage requirements. If it  
5. INSTALLATION  
25  
Download from Www.Somanuals.com. All Manuals Search And Download.  
does not comply, then it is necessary to switch the operating voltage to the correct supply requirements  
BEFORE turning on the unit, otherwise the unit could be severely damaged. You will find this combined fuse  
holder/voltage selector at the back, adjacent to the IEC receptacle. IMPORTANT: This does not apply for  
general export models which are built for one operating voltage only.  
The AC voltage selection is defined by the position of the fuse holder. If you intend to change the operating  
voltage, remove the fuse holder and twist it by 180 degrees before you reinsert it. Matching the two markers  
monitors the selected voltage.  
+
If the unit is switched to an other operating voltage, the ruse rating must be changed. See the  
technical specifications in the appendix  
A safety fuse protects the unit from serious defects. If the fuse blows, this is a warning sign and always  
indicates that the circuit is overloaded. The fault must always be repaired before the fuse is replaced. If the  
safety fuse is faulty and needs replacing after the unit is repaired, please make sure that you replace it only  
with the identical type and rating. NEVER use fuses of different ratings or cover faulty fuses with aluminium foil.  
This can cause fire and electric shocks and will endanger your life and the lives of others.  
5.3 Audio connections  
As standard, the BEHRINGER FEEDBACK DESTROYER PRO is installed with electronically servo-balanced  
inputs and outputs. The new circuit design features automatic hum and noise reduction for balanced signals  
and thus allows for trouble-free operation, even at high operating levels. Externally induced mains hum etc. will  
be effectively suppressed. The automatic servo-function recognizes the presence of unbalanced connectors  
and adjusts the nominal level internally to avoid level differences between the input and output signals (correc-  
tion 6 dB).  
+
Please ensure that only qualified persons install and operate the FEEDBACK DESTROYER PRO.  
During installation and operation the user must have sufficient electrical contact to earth.  
Electrostatic charges might affect the operation of the FEEDBACK DESTROYER PRO!  
Output  
Cable  
Input  
Ground  
Positive  
Negative  
Pin 1  
2
1
1
2
Shield  
(+) Signal + Hum  
(-) Signal + Hum  
Pin 2 = (+) Signal  
Pin 3 = (-) Signal  
(+)Hum + Signal  
(-)Hum + Signal  
3
3
2 x Signal  
= Signal + 6 dB  
RFI and Hum  
Fig. 5.1: Compensation of interference with balanced connections  
26  
5. INSTALLATION  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Unbalanced use of  
Balanced use of  
mono 1/4" jack plugs  
stereo 1/4" jack plugs  
Tip =  
Signal  
Tip =  
hot (+ve)  
Ring =  
cold (-ve)  
Sleeve =  
Ground / Shield  
E
Sleeve =  
Ground / Shield  
Tip  
Tip  
Ring  
Sleeve  
Sleeve  
Strain relief clamp  
Strain relief clamp  
For connection of balanced and  
unbalanced plugs, ring and sleeve have  
to be bridged at the stereo plug.  
Balanced use with XLR connectors  
2
1
1
2
1 = Ground / Shield  
2 = hot (+ve)  
3 = cold (-ve)  
3
3
Input  
Output  
For unbalanced use pin 1 and pin 3 have to be bridged  
Fig. 5.2: Different plug types  
5.4 MIDI connections  
The MIDI standard was developed in the early 1980s to allow electronic musical instruments from different  
manufacturers to communicate with each other. The use of MIDI has developed over the intervening years to  
the stage where it is now common to find complete recording studios operating entirely on a MIDI basis. The  
centerpiece in such a studio is usually a computer running a sequencer software which not only controls  
various keyboards, samplers and sound modules, but can also run the programming of outboard effect devices,  
typically digital reverberation and delay units. The FEEDBACK DESTROYER PRO may be controlled in real  
time in this studio environment.  
+
MIDI for Musical Instruments Digital Interface.  
The MIDI connectors found on the rear panel are of the universally used 5 pin DIN type. You require suitable  
MIDI cables to connect the FEEDBACK DESTROYER PRO to other MIDI devices. Normally complete cables  
will be purchased for this use, you can of course make your own, using a high quality cable with two cores and  
shielding (like microphone cable), with as connectors two good 180 degree DIN plugs. Pin 2 (center) is con-  
nected to the cable’s shield, pins 4 and 5 (left and right next to 2) carry the two cores, pins 1 and 3 are not  
used. MIDI cables should have a maximum length not exceeding 45 feet.  
5. INSTALLATION  
27  
Download from Www.Somanuals.com. All Manuals Search And Download.  
5.5 Operating level Switch  
To adapt the FEEDBACK DESTROYER PRO to the used operating level, the unit can be switched between  
homerecording level (-10 dBV) and professional level (+4 dBu). Use the LED bars on the frontpanel to deter-  
mine the optimal setting. The Level indicators should read somewhere between -10 and -6 dB, while the clip  
LED should not light up at all.  
6. APPENDIX  
6.1 Frequency chart  
In order to maintain a better survey only every second value is registered in the table. The adjustable values do  
not exactly fit into a 1/60 octave interval, because also the ISO frequencies do not perfectly fit into a physical  
1/3 octave interval. Rather a linear approximation is used to specify the values.  
Background  
f1,f2, ...  
ISO frequency  
1 third = 20/60 octave (idealized ISO interval)  
f
− fn  
(
)
n +1  
increment  
∆ fn =  
20  
Display  
-9/60  
-8/60  
-6/60  
-4/60  
-2/60  
+2/60  
+4/60  
+6/60  
+8/60 +10/60 Display  
ISO  
Hz  
20.5  
25.7  
32.4  
41  
51  
65  
21  
26.3  
33.2  
42  
53  
66  
21.5  
27  
34.1  
43  
54  
68  
22  
27.6  
34.9  
44  
55  
70  
22.5  
28.3  
35.8  
45  
57  
71.5  
90  
113  
143  
180  
Hz  
Hz  
Hz  
Hz  
Hz  
Hz  
Hz  
Hz  
Hz  
Hz  
20  
25  
32  
40  
50  
63  
80  
100  
125  
160  
20  
25  
31.5  
40  
50  
63  
20  
25  
32  
40  
50  
63  
80  
100  
125  
160  
Hz 22.8  
Hz 28.6  
Hz 36.2  
Hz 45.5  
Hz  
Hz 72.4  
Hz  
Hz  
Hz  
23  
28.9  
36.6  
46  
58  
73  
92  
115  
146  
23.5  
29.6  
37.5  
47  
59  
75  
94  
118  
150  
24  
30.2  
38.3  
48  
60  
77  
96  
120  
153  
24.5  
30.9  
39.2  
49  
62  
78  
98  
123  
157  
57  
82  
84  
86  
88  
80  
91  
114  
144  
103  
129  
164  
105  
132  
168  
108  
136  
172  
110  
139  
176  
100  
125  
160  
kHz 182  
kHz 228  
kHz 286  
kHz 362  
kHz 455  
kHz 572  
kHz 724  
kHz 910  
kHz 1138  
kHz 1443  
184  
230  
289  
366  
460  
578  
732  
920  
1150  
1460  
188  
235  
296  
375  
470  
591  
749  
940  
1175  
1495  
192  
240  
302  
383  
480  
604  
766  
960  
1200  
1530  
196  
245  
309  
392  
490  
617  
783  
980  
1225  
1565  
205  
257  
324  
410  
513  
647  
820  
1025  
1285  
1640  
210  
263  
332  
420  
526  
664  
840  
1050  
1320  
1680  
215  
270  
341  
430  
539  
681  
860  
1075  
1355  
1720  
220  
276  
349  
440  
552  
698  
880  
1100  
1390  
1760  
225  
283  
358  
450  
565  
715  
900  
1125  
1425  
1800  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
.20  
.25  
.32  
.40  
.50  
.63  
.80  
1.00  
1.25  
1.60  
200  
250  
315  
400  
500  
630  
800  
1000  
1250  
1600  
.20  
.25  
.32  
.40  
.50  
.63  
.80  
1.00  
1.25  
1.60  
kHz 1820  
kHz 2275  
kHz 2858  
kHz 3618  
kHz 4550  
kHz 5715  
kHz 7235  
kHz 9100  
1840  
2300  
2890  
3660  
4600  
5780  
7320  
9200  
1880  
2350  
2955  
3745  
4700  
5910  
7490  
9400  
1920  
2400  
3020  
3830  
4800  
6040  
7660  
9600  
1960  
2450  
3085  
3915  
4900  
6170  
7830  
9800  
2050  
2565  
3235  
4100  
5130  
6470  
8200  
2100  
2630  
3320  
4200  
5260  
6640  
8400  
2150  
2695  
3405  
4300  
5390  
6810  
8600  
2200  
2760  
3490  
4400  
5520  
6980  
8800  
2250  
2825  
3575  
4500  
5650  
7150  
9000  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
kHz  
2.0  
2.5  
3.2  
4.0  
5.0  
6.3  
8.0  
10.0  
12.5  
16.0  
20  
2000  
2500  
3150  
4000  
5000  
6300  
8000  
10000  
12500  
16000  
20000  
2.0  
2.5  
3.2  
4.0  
5.0  
6.3  
8.0  
10.0  
12.5  
16.0  
20  
10250 10500 10750 11000 11250  
12850 13200 13550 13900 14250  
16400 16800 17200 17600 18000  
kHz 11375 11500 11750 12000 12250  
kHz 14425 14600 14950 15300 15650  
kHz 18200 18400 18800 19200 19600  
Tab. 6.1: frequency chart  
28  
6. APPENDIX  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6.2 Preset table  
Preset Filter 1 Filter 2 Filter 3 Filter 4 Filter 5 Filter 6 Filter 7 Filter 8 Filter 9 Filter 10 Filter 11 Filter 12  
MONO: 9 single shot filters attenuate room resonances before 3 automatic filters destroy variable feedbacks  
1
L
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
AU  
AU  
AU  
AU  
AU  
AU  
R
2 x MONITOR AS FEEDBACK DESTROYER ONLY: 7 single shots / 5 automatic filters for most monitor setups  
E
2
L
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
R
MONO AUTO PILOT: 12 Filters per channel constantly chase and destroy feedbacks.  
3
L
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
AU  
R
STEREO PARAMETRIC EQ: Preset with 12 ISO frequencies, all set to 1/3 Oct., Gain + 0 dB  
125 Hz 160 Hz 200 Hz 250 Hz 315 Hz 400 Hz 500 Hz 630 Hz 800 Hz 1 k 1.25 k 1.6 k  
4
Couple  
STEREO PARAMETRIC EQ: Preset with 12 ISO frequencies, all set to 2/3 Oct., Gain + 0 dB  
100 Hz 160 Hz 250 Hz 400 Hz 630 Hz 1 k 1.6 k 2.5 k 4 k 6.3 k  
5
Couple  
40 Hz  
63 Hz  
2 x MONO: Sample monitoring, left for handheld (lead) microphone(s), right for fixed (backing) ones  
6
L
SI  
SI  
SI  
SI  
SI  
SI  
AU  
SI  
AU  
SI  
AU  
AU  
AU  
AU  
AU  
AU  
PA def PA def PA def PA def  
PA def PA def PA def PA def  
R
MONO PARAMETRIC AND SINGLE SHOT FILTERS: A good start for a monitor equalization  
7
L
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
PA def PA def PA def PA def  
PA def PA def PA def PA def  
R
STEREO FOH EQ, providing 4 parametric EQ’s (low roll off in filter 1 and 2), plus 8 single shot filters  
8
Couple  
PA  
PA  
PA d.  
PA d.  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
40 Hz  
1 Oct.  
-8 dB  
80 Hz  
1 Oct.  
-4 dB  
Channels coupled, changes on one channel are valid for both  
MONO FREE  
9
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
AU  
AU  
AU  
AU  
PA  
PA  
PA  
PA  
PA  
PA  
L, R  
STEREO FREE  
PA PA  
10  
Couple  
SI  
SI  
SI  
SI  
SI  
SI  
SI  
AU  
AU  
PA  
Tab. 6.2: Factory presets  
6. APPENDIX  
29  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6.3 MIDI implementation  
Parameter Name  
Display Range  
Midi Control  
Number  
Control Value  
Range  
LEDs  
Couple  
0
Left  
1
Right IN on IN off IN flashing  
Filter Select  
Filter Mode  
Engine  
1..12  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
0..11  
0..3  
OF, PA, AU, SI  
0,1,2  
0..30  
0..19  
0..119  
0..64  
0..6  
2
Frequency  
Fine (1/60 Oct)  
Bandwidth  
Gain  
20 (Hz)..20 (kHz)  
-9..+10  
1..120  
-48..+16  
-3..-9  
Feedback Threshold  
Store  
1..10  
0..9  
In/Out  
0..2  
2
1
0
Tab. 6.3: Controller functions with MIDI  
Function  
Transmitted Recognized  
Remarks  
Basic  
Channel  
Default  
Changed  
Default  
OFF, 1 - 16 OFF, 1 - 16 memorized  
OFF, 1 - 16 OFF, 1 - 16  
1,2,3,4  
1,2,3,4  
Mode  
Messages  
Altered  
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Note Number  
True Voice  
Note ON  
Note OFF  
Key´s  
Velocity  
After Touch  
Ch´s  
Pitch Bender  
Control  
X
X
O 10 - 19  
O 10 - 19  
see add. Table  
Progr.  
O (0-9)  
O (0-9)  
Change  
System Exclusive  
True #  
1-10  
O
X
X
X
1-10  
O
X
X
X
Song Pos  
Song Sel  
Tune  
System  
Common  
System  
Clock  
X
X
Real Time  
Commands  
Local ON/OFF  
All notes OFF  
Active Sense  
Reset  
X
X
X
X
X
X
X
X
Aux  
Messages  
X
X
Notes  
O = YES, X = NO  
Mode 1:  
Mode 2:  
Mode 3:  
Mode 4:  
OMNI ON, POLY  
OMNI ON, MONO  
OMNI OFF, POLY  
OMNI OFF, MONO  
Tab. 6.4: MIDI implementation chart  
30  
6. APPENDIX  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6.4 Specifications  
Analog Inputs  
Connectors  
XLR and 1/4" jack  
Type  
RF filtered, servo balanced input  
Impedance  
Nominal Operating Level  
Max. Input Level  
60 kOhms balanced, 30 kOhms unbalanced  
-10dBV to +4dBu  
+16 dBu at +4 dB nominal level, +2 dBV at -10 dBV nominal level  
E
Analog Outputs  
Connectors  
Type  
Impedance  
Max. Output Level  
XLR and 1/4" jack  
Electronically servo-balanced output stage  
60 Ohms balanced, 30 Ohms unbalanced  
+16 dBu at +4 dB nominal level, +2 dBV at -10 dBV nominal level  
System specifications  
Bandwidth  
Noise  
THD  
Crosstalk  
20 Hz to 20 kHz, -3 dB  
>-94 dB, unweighted, 20 Hz to 20 kHz  
0.0075 % typ. @ +4 dBu, 1 kHz, Gain 1  
< -76 dB  
MIDI Interface  
Type  
5-Pin-DIN-Socket IN / OUT / THRU  
Digital Processing  
Converters  
Sampling Rate  
20-bit Sigma-Delta, 64/128-times Oversampling  
46,875 kHz  
Display  
Type  
2 ½-digit numeric LED-Display  
Power Supply  
Mains Voltages  
USA/Canada  
U.K./Australia  
Europe  
~ 120 V AC, 60 Hz  
~ 240 V AC, 50 Hz  
~ 230 V AC, 50 Hz  
General Export Model  
~ 100-120 V AC, ~ 200-240 V AC, 50-60 Hz  
Fuse  
100-120 V AC: 125 mA (slow-blow)  
200-240 V AC: 63 mA (slow-blow)  
10 Watts  
Power Consumption  
Mains Connection  
Standard IEC receptacle  
Physical  
Dimensions (H * W * D)  
1 3/4” (44.5 mm) * 19” (482.6 mm) * 7 1/2” (190.5 mm)  
Net Weight  
Shipping Weight  
± 2 kg  
± 3 kg  
BEHRINGER is constantly striving to maintain the highest professional standards. As a result of these efforts, modifications may be  
made from time to time to existing products without prior notice. Specifications and appearance may differ from those listed or  
shown.  
6. APPENDIX  
31  
Download from Www.Somanuals.com. All Manuals Search And Download.  
7. WARRANTY  
§ 1 WARRANTY CARD  
this modification/adaptation shall not be considered a defect in  
materials or workmanship. The warranty does not cover any  
such modification/adaptation, irrespective of whether it was  
carried out properly or not. Under the terms of this warranty,  
BEHRINGER INTERNATIONAL shall not be held responsible for  
any cost resulting from such a modification/adaptation.  
To be protected by this warranty, the buyer must complete and  
return the enclosed warranty card (signed/stamped by retail  
dealer) within 14 days of the date of purchase to BEHRINGER  
INTERNATIONAL (address see § 3). Failure to return the card in  
due time (date as per postmark) will void any extended warranty  
claims.  
3. Free inspections, maintenance/repair work and replacement  
of parts are expressly excluded from this warranty, in particular  
if caused by inappropriate use. Likewise, the warranty does not  
cover defects of expendable parts caused by normal wear of  
the product. Expendable parts are typically faders, potentiom-  
eters, switches and similar components.  
§ 2 WARRANTY  
1. BEHRINGER INTERNATIONAL warrants the mechanical and  
electronic components of this product to be free of defects in  
material and workmanship for a period of one (1) year from the  
original date of purchase, in accordance with the warranty regu-  
lations described below. If any defects occur within the speci-  
fied warranty period that are not caused by normal wear or  
inappropriate use, BEHRINGER INTERNATIONAL shall, at its sole  
discretion, either repair or replace the product.  
4. Damages/defects caused by the following conditions are not  
covered by this warranty:  
s
misuse, neglect or failure to operate the unit in compliance  
with the instructions given in the user or service manuals.  
2. If the warranty claim proves to be justified, the product will be  
returned freight prepaid by BEHRINGER INTERNATIONAL within  
Germany. Outside of Germany, the product will be returned at  
the buyer’s expense.  
s
connection or operation of the unit in any way that does not  
comply with the technical or safety regulations applicable in  
the country where the product is used.  
3. Warranty claims other than those indicated above are ex-  
pressly excluded.  
s
damages/defects that are caused by force majeure or by  
any other condition beyond the control of BEHRINGER  
INTERNATIONAL.  
§ 3 RETURN AUTHORIZATION NUMBER  
5. Any repair carried out by unauthorized personnel will void the  
warranty.  
1. To obtain warranty service, the buyer must call BEHRINGER  
INTERNATIONAL during normal business hours BEFORE return-  
ing the product (Tel.: +49 (0) 21 54 / 92 06 66). All inquiries must  
be accompanied by a description of the problem. BEHRINGER  
INTERNATIONAL will then issue a return authorization number.  
6. Products which do not meet the terms of this warranty will be  
repaired exclusively at the buyer’s expense. BEHRINGER  
INTERNATIONAL will inform the buyer of any such circumstance.  
If the buyer fails to submit a written repair order within 4 weeks  
after notification, BEHRINGER INTERNATIONAL will return the  
unit C.O.D. with a separate invoice for freight and packing. Such  
cost will also be invoiced separately when the buyer has sent in  
a written repair order.  
2. The product must be returned in its original shipping carton,  
together with the return authorization number, to the following  
address:  
BEHRINGER INTERNATIONAL GmbH  
Service Department  
§ 5 WARRANTY TRANSFERABILITY  
Hanns-Martin-Schleyer-Str. 36-38  
D - 47877 Willich-Münchheide  
This warranty is extended exclusively to the original buyer (cus-  
tomer of retail dealer) and is not transferable to anyone who  
may subsequently purchase this product. No other person (re-  
tail dealer, etc.) shall be entitled to give any warranty promise on  
behalf of BEHRINGER INTERNATIONAL.  
3. Shipments without freight prepaid will not be accepted.  
§ 4 WARRANTY REGULATIONS  
§ 6 CLAIM FOR DAMAGES  
1. Warranty services will be furnished only if the product is  
accompanied by an original retail dealer’s invoice. Any product  
deemed eligible for repair or replacement by BEHRINGER INTER-  
NATIONAL under the terms of this warranty will be repaired or  
replaced within 30 days of receipt of the product at BEHRINGER  
INTERNATIONAL.  
Failure of BEHRINGER INTERNATIONAL to provide proper war-  
ranty service shall not entitle the buyer to claim (consequential)  
damages. In no event shall the liability of BEHRINGER INTERNA-  
TIONAL exceed the invoiced value of the product.  
§ 7 OTHER WARRANTY RIGHTS  
This warranty does not exclude or limit the buyer’s statutory  
rights provided by national law, in particular, any such rights  
against the seller that arise from a legally effective purchase  
contract.  
2. If the product needs to be modified or adapted in order to  
comply with applicable technical or safety standards on a na-  
tional or local level, in any country which is not the country for  
which the product was originally developed and manufactured,  
The information contained in this manual is subject to change without notice. No part of this manual may be reproduced or  
transmitted in any form or by any means, electronic or mechanical, including photocopying and recording of any kind, for any  
purpose, without the express written permission of BEHRINGER GmbH.  
BEHRINGER, ULTRA-CURVE and FEEDBACK DESTROYER are registered trademarks.  
ALL RIGHTS RESERVED © 1998 BEHRINGER.  
BEHRINGER INTERNATIONAL GmbH, Hanns-Martin-Schleyer-Str. 36-38, D-47877 Willich-Münchheide II  
Tel. +49 (0) 21 54 / 92 06-0, Fax +49 (0) 21 54 / 92 06-30  
32  
7. WARRANTY  
Download from Www.Somanuals.com. All Manuals Search And Download.  

2nd Ave Coffeemaker D 490 Zoom User Manual
Accton Technology Fondue Maker POWER 3004E User Manual
ADC Network Router 1900 PCS User Manual
ADTRAN Switch TRDDS R User Manual
ADTRAN Telephone 604 User Manual
Agri Fab Outdoor Cart 45 01772 User Manual
AKG Acoustics Microphone C747 V11 User Manual
American Audio Stereo Amplifier M822FX User Manual
Audiovox Automobile Alarm PRO9801C User Manual
Beko Blender BKK2152 User Manual