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8

FEEDBACK DESTROYER PRO DSP1124P

2. APPLICATIONS

The DSP1124P is used 

exclusively

 to 

eliminate feedback in FOH and monitor mixes

.

Before you go on, please note the following two remarks:

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The FEEDBACK DESTROYER PRO is not intended to be connected directly to the microphones!

If this is unavoidable, then we recommend our proven BEHRINGER SHARK DSP110 instead,

which is equipped with a dedicated microphone preamplifier.

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No processing device can undo the mistakes made when placing the microphones!  So, when

you  set  up  your  mics,  use  them  according  to  their  directivity  and  feedback  susceptibility

(see chapter 8 “PROBLEMS DO HAVE A CAUSE ...”).

2.1 Level setting

Take  care  to  set  levels  properly  on  the  DSP1124P,  so  as  to  successfully  employ  the  FEEDBACK

DESTROYER PRO to remove feedback. Use the LED LEVEL METER 

. Make sure that the top Clip LEDs

flicker only rarely, but never light up all the time.
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.

2.2 Using the FEEDBACK DESTROYER PRO in the monitor path

Your DSP1124P is equipped with two channels. In 

Couple

 mode (see control elements 

 and 

), these

two channels are linked. But you can also use them separately, for example, to protect two dedicated monitor

paths against feedback.
Monitor mixes are realized either via the pre-fader Aux Sends on an FOH console, or via a (usually stage-

mount) monitor mixer. When using an additional monitor mixer on the stage, you need a so-called splitter to

route the single microphone signals both to the FOH console and to the monitor mixer. When using the FOH

console for the monitor mix, the stage microphones are connected directly to the console (if necessary, via a

so-called stage box).
In both cases, separate monitor mixes are created for the musicians, which can then be provided from the

console  outputs  (usually  via  the  Aux  Send  outputs).  Owing  to  its  2-channel  design,  your  FEEDBACK

DESTROYER PRO allows you to protect two monitor paths against feedback. To do so, connect the pre-fader

Aux Send outputs on your console to the inputs of the DSP1124 (as shown in fig. 2.1). Then, connect the

inputs of the monitor power amps to the outputs of the FEEDBACK DESTROYER PRO (see fig. 2.1).
As already mentioned, monitor paths are particularly susceptible to feedback. When vocal microphones are

not installed in a fixed position, things become even worse, so it really makes sense to protect the monitor

paths against feedback. Another positive side effect of using the DSP1124P in the monitor path is the fact that

you can raise the volume levels considerably.
As you can see, your DSP1124P is a perfect tool to protect two independent monitor paths. But why is that so

important? Because “monitoring” is a complex task. Usually, each monitor path is used for an independent mix

comprising a variety of signal sources. This is the only way to ensure that each performer on the stage can

hear exactly what he or she wants.

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Owing to its 2-channel design, the DSP1124P is the perfect tool for application in two separate

monitor  paths.  However,  if  you  need  to  protect  four  monitors  against  feedback,  we

recommend that you use a second DSP1124P.

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If possible, all monitor paths should be set pre-fader, as this leaves the monitor mix unaffected

from any changes made to the FOH mix.

2. APPLICATIONS

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Summary of Contents for FEEDBACK DESTROYER PRO DSP1124P

Page 1: ...User s Manual Version 1 0 February 2001 www behringer com FEEDBACK DESTROYER PRO DSP1124P ENGLISH Downloaded from www g7syw com www g7syw com...

Page 2: ...hrough 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 Sou...

Page 3: ...ber 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...

Page 4: ...ode 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 design...

Page 5: ...CTURE PRESETS FILTERS OPERATING MODES 13 5 1 Priming the DSP1124P for P A and monitor applications 13 6 OPERATING MODES OF THE DSP1124P 14 6 1 Off mode OF 14 6 2 Manual filters PA parametric equalizer...

Page 6: ...itches and further selected components The FEEDBACK DESTROYER PRO employs SMD technology Surface Mounted Device These subminiature components known from aerospace technology allow for an extreme packi...

Page 7: ...o produce feedback the first section is the so called front of house mix FOH i e the public address mix which is reproduced by one or several amplifiers plus several loudspeakers directed at the audie...

Page 8: ...d a so called splitter to route the single microphone signals both to the FOH console and to the monitor mixer When using the FOH console for the monitor mix the stage microphones are connected direct...

Page 9: ...pre compressor in this way the signal is taken at the insert jack passes the DSP1124P then the compressor and is finally routed back to the insert jack Ideally your mixer has sub groups with dedicate...

Page 10: ...nitor paths is being used this procedure must be done separately for each path Repeat for each susceptible mic channel s Using the DSP1124P on channel sub group inserts Deliberately induce feedback by...

Page 11: ...mode SI and Auto mode AU Please read chapter 6 OPERATING MODES OF THE DSP1124P Pressing the FILTER MODE and GAIN keys simultaneously allows you to adjust the sensitivity of the feedback suppression t...

Page 12: ...elements 17 Use the OPERATING LEVEL switch to change from home recording level 10 dBV to studio level 4 dBu and vice versa The level meters are adapted automatically to the selected nominal level so...

Page 13: ...0 be unlocked so as to be able to detect new feedback frequencies Basically all active filters both in AU or SI mode are represented by flashing LEDs in the STATUS INDICATOR When feedback has been det...

Page 14: ...plications Example During a pure speech transmission the feedback sensitivity can be lowered to 9 dB In this way the algorithm would recognize and suppress feedback even faster On the other hand a hig...

Page 15: ...each preset as you scroll through the preset list with the JOG WHEEL Thus the DSP1124P makes sure that no unwanted programs are loaded unintentionally Additionally you can rotate the JOG WHEEL at hig...

Page 16: ...cal proportion between the displayed value and the absolute frequency as well as a guide to find the desired frequency quickly are listed in the appendix chapter 11 1 frequency chart The bandwidth of...

Page 17: ...small c channel The JOG WHEEL adjusts a channel from 1 through 16 To switch off the MIDI function simply select 0 displayed as On the second page you can select MIDI Omni mode i e the unit transmits r...

Page 18: ...ou press the IN OUT key again on the sixth page the FEEDBACK DESTROYER PRO quits MIDI mode You can also use any other key to leave the MIDI setup menu The full featured MIDI implementation of the FEED...

Page 19: ...ease 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...

Page 20: ...192 196 200 205 210 215 220 225 20 kHz 25 kHz 228 230 235 240 245 250 257 263 270 276 283 25 kHz 32 kHz 286 289 296 302 309 315 324 332 341 349 358 32 kHz 40 kHz 362 366 375 383 392 400 410 420 430 44...

Page 21: ...I SI SI SI SI SI PA def PA def PA def PA def 8 Couple PA PA PA d PA d SI SI SI SI SI SI SI SI 40 Hz 80 Hz 1 Oct 1 Oct 8 dB 4 dB 9 L R SI SI SI SI SI SI SI AU AU PA PA PA SI SI SI SI SI SI SI AU AU PA...

Page 22: ...Time Clock Commands X X X X Aux Messages Local ON OFF All notes OFF Active Sense Reset X X X X X X X X Notes O YES X NO Mode 1 OMNI ON POLY Mode 2 OMNI ON MONO Mode 3 OMNI OFF POLY Mode 4 OMNI OFF MO...

Page 23: ...et IN OUT THRU DIGITAL PROCESSING Converters 24 bit Sigma Delta 64 128 times Oversampling Sampling Rate 46 875 kHz DISPLAY Type 2 digit numeric LED Display POWER SUPPLY Mains Voltages USA Canada 120 V...

Page 24: ...eipt of the product at BEHRINGER 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...

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