S412P STUDIO SERIES (serv.man3) - JBL Audio User Guide / Operation Manual. Page 7

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7
T R O U B L E S H O O T I N G
If there is no sound from 
any of the speakers:
• Check that receiver/
amplifier is on and that a
source is playing.
• Review proper operation
of your receiver/amplifier.
If there is no sound coming
from one speaker:
• Check the “Balance”
control on your
receiver/amplifier.
• Check all wires and
connections between
receiver/amplifier 
and speakers.
• Make sure all wires are 
connected. Make sure
none of the speaker wires
are frayed, cut or
punctured.
If the system plays at low
volumes but shuts off as
volume is increased:
• Check all wires and
connections between
receiver/amplifier 
and speakers.
• Make sure all wires are
connected. Make sure
none of the speaker 
wires are frayed, cut or
punctured.
• If more than one pair of
main speakers is being
used, check the minimum
impedance requirements of
your receiver/amplifier.
If there is no (or low) bass
output:
• Make sure the polarities 
(+ and –) of the left and
right “Speaker Inputs” are 
connected properly.
• Make sure that the
speaker is plugged into an
active electrical outlet and
switched on, and that the
green LEDs are displayed.
If you used the LFE input
and there is no sound from
the subwoofer:
• Check that receiver/
amplifier is on and that a
source is playing.
• Make sure that the
speaker is plugged into an
active electrical outlet.
• Check all wires and
connections between
receiver/amplifier and
speakers.
• Make sure all wires are
connected. Review the
“Line-Level Connections”
section on page 5 of this
manual and make sure that
a single RCA patch cord 
is connected to each
loudspeaker from the 
Y-Connector plugged into
the receiver/amplifier’s
subwoofer output. Make
sure none of the speaker
wires are frayed, cut or
punctured.
• Review proper operation
of your receiver/amplifier,
including making sure that
you have configured your
receiver so that the sub-
woofer output is active.
If you are using the S412P
LFE/Subwoofer input and
the bass level decreases
(instead of increasing)
when you turn the LFE/
Subwoofer Level knob
clockwise:
• Recheck to make sure
that your receiver or
amplifier-speaker outputs
are correctly connected to
the S412P speaker inputs
(gold-plated binding posts),
(+) to (+) and (–) to (–). The
S412P (+) terminal has a red
stripe and is located on the
right-hand side, below the
letter “L” of the molded JBL
logo, when looking directly at
the back of the S412P.
• If the wires are connected
properly, the confusion may
be attributable to the design
of your receiver/ amplifier.
Your unit may have inverting
inputs, which reverse the
polarity of the signal
between the inputs and
outputs of the amplifier. To
check if this is the case,
reverse the speaker con-
nections for ALL S412Ps in
your system (and disconnect
any other speakers in the
system) so that the
receiver/amplifier’s (+)
connector is connected to
each S412P’s (–) (black
stripe) speaker connector.
If you do this and the
S412Ps function properly
(bass increases as you turn
your LFE/Subwoofer level-
control knobs clockwise),
your receiver/amp uses
inverting inputs. This is not
a problem. Simply connect
all of the speakers in your
system the same way, with
the receiver or amplifier’s
(+) terminal to the speaker’s
(–) terminal, and the receiver
or amplifier’s (–) terminal to
the speaker’s (+) terminal.
Studio Series-S412P OM  10/19/99  1:00 PM  Page 7
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