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Feedback destroyer pro fbq2496, What causes feedback, Control elements and connections – Behringer FBQ2496 User Manual

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FEEDBACK DESTROYER PRO FBQ2496

immediately as well as the transportation company from

which you took delivery. Otherwise, all claims for

replacement/repair may be rendered invalid.

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Please always use the original packaging to avoid damage

due to storage or shipping.

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Never let unsupervised children play with the

FBQ2496 or with its packaging.

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Please dispose of all packaging materials in an

environmentally friendly fashion.

1.1.2 Initial operation

Be sure that there is enough space around the unit for cooling. To

avoid overheating, do not place the FBQ2496 on top of power

amps or near radiators, etc.

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Blown fuses must be replaced by fuses of the same type

and rating. Please refer to the “SPECIFICATIONS” for

further details.

The mains connection is made using the enclosed power cord and

a standard IEC receptacle. It meets all international safety

certification requirements.

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Please make sure that all equipment is properly grounded

at all times. For your own safety, never remove or disable

the ground conductor of the unit or of the AC power cord.

1.1.3 Online registration

Please do remember to register your new BEHRINGER equipment

right after your purchase by visiting www.behringer.com

(alternatively www.behringer.de) and kindly read the terms and

conditions of our warranty carefully.
Should your BEHRINGER product malfunction, our goal is to have

it repaired as quickly as possible. To arrange for warranty service,

please contact the retailer from whom the equipment was

purchased. Should your BEHRINGER dealer not be located in

your vicinity, you may directly contact one of our subsidiaries.

Corresponding contact information is included in the original

equipment packaging (Global Contact Information/European

Contact Information). Should your country not be listed, please

contact the distributor nearest you. A list of distributors can be

found in the support area of our website (www.behringer.com/

support).
Registering your purchase and equipment with us helps us process

your repair claims quicker and more efficiently.
Thank you for your cooperation!

2. WHAT CAUSES FEEDBACK?

Fig. 2.1: How a feedback loop is created

A feedback loop is created when a microphone signal is first

reproduced on an amplifier, and is then picked up again by the

same microphone (with the same phasing). Then, it is amplified

and reproduced again. This feedback loop may, under certain

circumstances, keep on occurring and could escalate out of control.
With P.A. applications, there are two major types of setups in

which feedback can occur:
s

Front mix (also called F.O.H. = “front of house”) refers to the

mix being created when a signal from a mixing console is

amplified by one or more power amplifiers and is fed into

loudspeakers facing the audience.

s

Monitor mix refers to the mix that also originates in the

mixing console but ends up driving one or more stage

monitors. Unlike FOH speakers, a stage monitor makes the

music program audible to individual musicians.

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Please bear in mind that high volume levels can damage

both your hearing and your equipment. Be sure to always

select an appropriate volume level.

3. CONTROL ELEMENTS AND

CONNECTIONS

3.1 The front

Fig. 3.1: Control elements on FBQ2496’s left side

LEVEL METER

The LEVEL METER lets you monitor the input level. Eight

LEDs are available per channel. If the Clip LED lights up,

digital distortion may occur on FBQ2496’s input. In this case,

reduce the input level.
LEARN button

A quick tap on the LEARN button (LED lights up) gets you

into the LEARN mode. The FBQ2496 will immediately start

looking for critical frequencies and will deploy as many

Single-Shot filters as necessary (of course, music or noise

has to be present in the room for this to work). Besides, using

the wheel

, you can manually determine the number of

Single-Shot filters (max. 20 per channel). See ch.4.1.

If you keep the LEARN button pressed for longer than one

second (LED blinks), the FBQ2496 generates progressively

louder impulses to generate feedback. The feedback thus

created enters the FBQ2496 at its input, where it is recognized

and suppressed. This mode is called AUTOLEARN (ch. 4.1).
PANIC

If unexpected feedback starts occurring during a performance,

pressing the PANIC button can help. As long as the button is

kept pressed (for a maximum of 1 second), your FBQ2496

rapidly searches for feedback frequencies and suppresses

them.
SPEECH

Pressing the SPEECH button increases the sensitivity of

feedback suppression; the FBQ2496 recognizes critical

frequencies sooner and deploys a filter that cuts in

appropriately.

Unlike with feedback caused by a distorting guitar, human

speech seldom produces signals that can mistakenly be

identified as feedback. Therefore, this mode is ideal for

situations in which only speech is being transmitted. Therefore,

your P.A. system will be substantially louder.
FREEZE

Once a particularly good FBQ2496 setting is achieved, you

can keep this setting by pressing the FREEZE button. All

Single-Shot and automatic filters are kept at their settings

until you press FREEZE again.
FILTER LIFT

The so-called “Filter Lifting Time” informs you about how

long an adjusted automatic filter can remain inactive before

its values are reset again. You can set this time by first briefly

pressing the FILTER LIFT button and then turning the wheel.

The following time lengths are available: 0 min, 1 min,

5 min, 10 min, 30 min, 60 min.

3. CONTROL ELEMENTS AND CONNECTIONS