Setting up the b1220dsp, 1 tweeter, 2 how to avoid feedback – Behringer Digital Processor-Controlled 600-Watt 12" PA Speaker System with Integrated Mixer B1220DSP User Manual

Page 6: Application examples, 1 presentations, 1 tweeter 3.2 how to avoid feedback

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EUROLIVE B1220DSP User Manual

The B1220DSP is equipped with a 2-band tone control. Each band allows you to

apply a maximum boost/cut of 15 dB, in its center position the equalizer is set

to neutral.

(7)

Use the EQ HIGH control to cut or boost the treble range by 15 dB. The cut-off

frequency is 12 kHz.

(8)

Use the EQ LOW control to cut or boost the bass range by 15 dB. The cut-off

frequency is 100 Hz.

(9)

The B1220DSP features a high-pass filter with a slope of 24 dB/oct.

to eliminate unwanted low-frequency content, such as pop sounds

produced by hand-held microphones, or rumble or wind noise when

using high-sensitivity microphones. The LOW CUT control adjusts the

cut-off frequency. If you want to use the B1220DSP in combination with

a subwoofer, you can use the high-pass filter to lower the bass range

reproduced by the subwoofer. This allows you to operate the B1220DSP

even without an external frequency crossover. Set the cut-off frequency to

the highest frequency that can be reproduced by the subwoofer.

(10)

The CONTOUR switch governs the dynamic contour filter:

SPEECH
Setting the CONTOUR switch to SPEECH (switch not pressed) will optimize the

frequency response for speech applications. This ensures better intelligibility.

MUSIC
Setting the CONTOUR switch to MUSIC (switch pressed) will optimize the

frequency response for music playback.

(11)

The TIMED TURNOFF switch activates the automatic turn-off function:

ON
When the switch is actuated (ON position), the automatic switch-off is active.

The loudspeaker is turned off auto matically when it receives no signal for more

than 3 minutes. As soon as a signal is received, the loudspeaker is switched

back on.

OFF
If the switch is not actuated (OFF position) then the speaker remains switched on

and can only be deactivated via the POWER switch (2).

(12)

A noise-gate allows you to eliminate unwanted noise during signal pauses.

This is done by a circuit that mutes the output when the signal level drops

below a preset threshold. Use the NOISE GATE control to determine the

threshold below which the noise-gate closes.

(13)

The TH LED lights up as soon as the signal level drops below the threshold

value adjusted with the NOISE GATE control (12) (the noise-gate closes).

3. Setting Up the B1220DSP

The sound of your B1220DSP largely depends on the room acoustics.

Please observe the following hints to get the most out of your B1220DSP.

3.1 Tweeter

High frequencies are the very part of the audio spectrum that ensure a clear

perception of sound and speech intelligibility. Although these frequencies can be

located most easily, they are also the first to be blocked acoustically. We therefore

recommend that you set up your speakers on speaker stands (not included),

so that the tweeter radiates its signals slightly above the heads of the audience.

This will ensure both an optimum dispersion of the high-frequency content and a

considerably improved speech intelligibility.

Fig. 3.1: B1220DSP mounted on a stand

3.2 How to avoid feedback

Always place the microphones (viewed from the audience) behind the B1220DSP,

never in front of it (Fig. 3.2). When you wish to adjust the controls on the

B1220DSP while holding a microphone, please approach the loudspeaker from

the rear to avoid feedback.

Fig. 3.2: Right and wrong positioning

To avoid feedback, it is recommended that you carefully select and direct the

microphones used. Basically, you should use microphones with a high directivity,

i.e. with a cardioid or hyper-cardioid polar pattern. Never hold a microphone so

that its main pick-up area points directly towards the loudspeaker. When you

hold it with its less sensitive side towards the speaker box, you can move closer

to the speaker.

If you encounter persistent feedback problems, consider using our
proven FEEDBACK DESTROYER PRO FBQ2496 for line-level signals.
For signals with line or microphone level, we recommend our
BEHRINGER SHARK DSP110.

4. Application Examples

4.1 Presentations

With just one B1220DSP and one or two dynamic microphones, you can set

up a basic audio system with very little effort. Thanks to the built-in mixer

section, you can connect the microphones directly to the B1220DSP. Mount the

B1220DSP on a speaker stand for optimum presentation and intelligibility of

announcements. If one B1220DSP is not enough, you can, of course, use a second

or even more loudspeakers.

Connecting microphones:

Turn the LEVEL controls (3) fully to the left

Connect your microphones to the MIC/LINE inputs

Switch on the B1220DSP

Turn the LEVEL controls (3) gradually clockwise to set the volume of your

choice. Observe the CLIP LEDs while adusting the volume. Make sure they

never shine constantly but only light up at peak levels

Use the LINE OUT connector (6) to connect an (optional) second B1220DSP

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