Behringer B1220 PRO ユーザーズマニュアル

EUROLIVE PROFESSIONAL SERIES

7. TROUBLESHOOTING

6.3 Stereo operation with a parallel stage

monitoring system and a subwoofer

This example shows the use of two B1520 PROs as FOH

loudspeakers and one B1220 PRO used as a floor monitor on

stage. The FOH loudspeakers reproduce the main stereo output

signal from the mixing console, while the stage monitor is fed an

independent monitor mix through a mono monitor send (Aux

Send). A separate subwoofer output feeds a B1800X PRO

subwoofer with the bass signal. Two stereo power amps are

required for this application, whereby one amp reproduces the

main stereo signal, and the other one reproduces both mono

signals (subwoofer and monitor signal).

Fig. 6.3: Stereo operation with a parallel stage monitoring

system and subwoofer

7. TROUBLESHOOTING

7.1 No signal when loudspeaker is connected

Make sure that your mixing console is indeed carrying a

signal (is the master fader raised? Are channels active?)

and that the gain control on your amp is turned up.

When using a crossover, make sure that the relevant

channels are active.

Check if the cable connection is interrupted/damaged

somewhere in your setup.

To test your configuration, connect another amp. If you

now get a signal, the power amp is the culprit.

To test your configuration, connect another speaker. If

you now get a signal, the fault lies within the speaker.

7.2 Signal present only on one channel

Make sure that your mixing console is working properly (is

the signal present on both outputs (L/R)?).

If using a crossover, check if the relevant channel is active.

Check if the cable connection to the silent channel and to

the corresponding speakers is interrupted/damaged

somewhere along the path.

Connect the silent loudspeaker onto the amp channel that

works properly. If you now get a signal, it is the amp channel

that is at fault. If you still can not hear anything, the fault lies

either within the loudspeaker or the cables used.

7.3 Signal distorted

Make sure that all signals on the mixing console have been

set to optimal levels in order to avoid distortion.

If using a crossover, check if all signals have been set to

correct levels.

Make sure that the power amp channels are not overdriving.

If so, turn the gain control down a little. However, it could

also be the case that your power amp doesnt have enough

power headroom, so that the required volume can not be

generated without starting to distort.

Make sure that the level of the signal getting into the speakers

is not too high, causing distortion.

Check your EQ settings. Excessively increasing the

frequencies can result in distortion.

If distortion is still occurring despite everything you have

tried to eliminate it, try connecting a different power amp. If

you no longer hear distortion, its cause was with the power

amp.

As a test, connect another speaker. If you no longer hear

distortion, its cause was with the loudspeaker (perhaps a

defective loudspeaker).

Check if the cable connection is interrupted/defective

somewhere along the path.

7.4 Treble signal too low

Check the EQ settings on your mixing console or on an

external EQ, if applicable.

Make sure that the tweeters on your loudspeakers are

positioned at the same height as the ears of the people in

the audience. If not, please modify the speaker position.

The internal tweeter fuse may have opened. In this case,

please contact a BEHRINGER service branch office near

you.