INTRODUCTION
SC305
CENTER CHANNEL
SPEAKER
Congratulations on choosing JBL
Series loudspeakers. Their highly
accurate, uncolored and balanced
sound character will greatly increase
your enjoyment of recorded music.
JBL speakers are built with careful
attention to detail, using only the
highest quality materials. They will
provide many years of excellent per-
formance.
OWNER’S
MANUAL
The SC305 Center Channel Speaker
is the result of concentrated efforts to
combine traditional JBL performance
values with elegant contemporary
appearance. Some of the engineer-
ing features of the SC305 are:
Smooth, extended response:
The 14mm Titanium Laminate dome
tweeter, dual 5" polymer laminated
cone drivers and carefully designed
dividing network deliver the clear,
crisp, quality sound reproduction
needed to deliver the accurate, intelli-
gible vocal information required by a
center channel speaker.
305
High Quality Crossover
Network: the computer-optimized
dividing network employs up to third-
order (18 dB per octave) crossover
sections. JBL's use of high quality
capacitors and low-loss/low-distortion
inductors assures freedom from
phase or amplitude distortions.
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4. Twist each set of thin wires into a
tightly-bunched spiral.
POWER HANDLING
Thanks to its high efficiency, the JBL
SC305 loudspeaker will produce reason-
able volume levels in a room of moderate
size with very little amplifier power.
5. At this point you need to identify a
visual difference between the two con-
ductors of each molded pair of speak-
er wire. Differentiating marks can be a
different color wire (copper or "silver");
a strand of yarn in one conductor; thin,
raised ribs on one part of the outer
insulation; or a printed "+" marking on
one of the insulators. It does not make
any difference which of the two
strands of wire go to (+) and (-) on the
speakers and amplifier, as long as
both speakers are connected identi-
cally. Push down on the button below
the terminal and insert the wire, or the
banana plug, through the hole (see
Fig. 3).
However, using a small amplifier to obtain
the desired volume listening levels may
lead to overdriving the amplifier. This will
generate high distortion levels and may
cause damage to your loudspeaker. For
the best performance, an amplifier should
be selected with an output rating that is
greater than the maximum power that will
be used. This margin of reserve power will
ensure that the amplifier will not attempt to
deliver more power than its design allows.
However, the amplifier's power rating per
channel must not exceed the maximum
recommended amplifier power for that spe-
cific loudspeaker model. Please see the
specification section for details. Following
these guidelines will provide virtually distor-
tion-free sound reproduction and long loud-
speaker life.
Blk Red
Center
(-) (+)
Speaker
• •
TROUBLESHOOTING
The vast majority of new speaker "malfunc-
tions" end up being traced to connections
or switch settings. Check the following tips
first, before requesting service.
AV Receiver
Center
• •
(-) (+)
Fig. 3
No sound at all or very faint sound from
the center channel speaker
1. Speaker wire has become disconnected.
2. One of the connections between sound
source and AV receiver/amp is faulty or
has become disconnected.
3. AV receiver/amp center channel mode
not selected. Please select a mode that
activates the center channel.
The red terminal on the loudspeaker
should be connected to the red or (+)
center channel connection terminal on
the AV receiver or amplifier, and the
black to the black or (-). Connecting
the loudspeaker in this manner
4. AV receiver/amp "audio direct" switch is
activated. This switch should be off to acti-
vate the 5 speaker surround mode.
5. Sound source (VDP, VCR,CD,cassette
deck, turntable) not turned on, not activat-
ed, not hooked up or not selected on AV
receiver/amp front panel.
ensures that it will be in phase; that is,
work together rather than in opposition
to the left and right channel speakers.
Connecting loudspeakers out of phase
will not damage them, but will result in
less bass and poor imaging.
Using the controls on your center
channel AV receiver/amp, adjust the
center channel level (volume) control
so that the sound from the center
speaker is the same level at your nor-
mal listening position, as the sound
from the left and right front speakers.
Speaker plays at low volumes but shuts
off as volume is increased OR sound
turns on and off intermittently
A few strands of speaker wire may be
shorting out. Recheck the connections.
Recheck the impedance of the amp.
3
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GENERAL CARE
SERVICE
The grille is held in place by pins near the
edges. To remove the grille, grasp it by
both top and bottom edges and pull gently.
To replace grille, re-position it carefully and
press gently at the corners. Do not push on
the center area of the grille.
Should your loudspeaker ever need ser-
vice, return it to the JBL dealer from whom
it was purchased. If for some reason this is
impractical, in the United States, call 800-
336-4JBL for your nearest warranty station.
Military personnel who purchased from
authorized military outlets should return
them to a similar outlet or contact:
ALA Associates Enterprises
The loudspeaker cabinet may be cleaned
with a slightly damp cloth. To remove dust
from the grille cloth, use a vacuum with a
brush attachment. Spots may be removed
with a commercial spot remover. Do not
use any cleaners or solvents on the
speaker drivers themselves.
985 Ponce de Leon Avenue
Atlanta, GA 30306
Phone: 800-875-4252
FAX: 404-873-3592
If purchased outside the United States,
contact your local distributor to make
arrangements for repair service. Do not
return products to the JBL factory with-
out prior authorization.
Specifications
SC305
High Frequency Dome Transducer
Low Frequency (High Polymer Laminate)
Crossover Frequency
14mm Titanium Laminate
5"(2)
2.7 kHz
Frequency Response (- 6 dB)
Sensitivity(1 Watt/1 meter)
Nominal Impedance
Recommended Amplifier Power*
External Dimensions (HxWxD)
External Dimensions (millimeters)
Weight (each)
100 Hz to20 kHz
87 dB
8 ohms
10 to 100 Watts
7"x 20"x 6-1/2"
178x508x165
15 lbs (6.8 kg)
18 lbs (8.2 kg)
Shipping Weight
*Undistorted continuous power per channel.
JBL continually strives to improve its products. New materials, production methods and
design refinements are introduced into existing models without notice as a routine expres-
sion of our design philosophy. For this reason, JBL loudspeakers may differ in some
respect from their published specifications and descriptions, but will always equal or
exceed the original specifications unless otherwise stated.
JBL Consumer Products, Inc.
240 Crossways Park West
Woodbury, NY 11797
8500 Balboa Blvd.
Northridge, CA 91329
800 336 4JBL
Part No. 75993
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