JBL SC305 User Manual

SC305
CENTER CHANNEL
SPEAKER
OWNER’S
MANUAL
INTRODUCTION
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 per­formance.
The SC305 Center Channel Speaker is the result of concentrated efforts to combine traditional JBL performance values with elegant contemporary appearance. Some of the engineer­ing 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, intelli­gible vocal information required by a center channel speaker.
305
SC
High Quality Crossover Network: the computer-optimized
dividing network employs up to third­order (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.
Magnetic Shielding: prevents stray
Fig.2
Fig.1
magnetic fields from creating any interference or distortion of the video picture. This allows placement of the SC305 directly on top of, or directly below the video monitor.
Cabinet Design: the multi-angled
cabinet provides options of locating the SC305 directly on top of the video monitor or on the floor in front of the monitor.
PLACEMENT
As the center channel contains the dialog and other central action sounds, the speaker should be locat­ed very close to the video monitor centered with the monitor's center line. The SC305 can be placed in two loca­tions:
1) On top of the video monitor.
Place the large flat bottom of the speaker directly on top of the monitor, with the front edge of the speaker grille flush with the edge of the moni­tor. The speaker grille/baffle should be pointing directly at the listener. See Fig. 1.
2) On the floor directly in front of the monitor.
cabinet on the floor so that the speak­er grille/baffle is pointing directly at the listener. The grille can be removed and re-installed so the JBL Logo is oriented properly. See Fig. 2.
Place the angled side of the
CENTER LINE
CONNECTIONS
To connect the SC305 to the center channel output of your AV receiver or amplifier, use two-conductor insulated wire. Your JBL dealer can recommend suitable cables, or you can buy wire at most hardware stores. We recom­mend #16 AWG wire as a minimum size. If your speaker is more than 30 feet (10 m) from your AV receiver or amplifier, use larger diameter wire. Connections are made at the termi­nals located on the back of the SC305 speaker. The terminals accept bare wire or dual banana plugs, either of which will provide easy, secure con­nections.
CENTER LINE
Preparing the hookup wire
1. First determine the distance
between the most distant speaker.
2. Now make the hookup wires for both speakers this length, even if one loudspeaker is much closer to your amplifier than the other. This will help maintain proper signal balance.
3. Strip off 3/8" of insulation from both ends of each conductor.
2
4. Twist each set of thin wires into a
AV Receiver
Center
(-) (+)
Center Speaker
Blk Red (-) (+)
Fig. 3
tightly-bunched spiral.
5. At this point you need to identify a visual difference between the two con­ductors of each molded pair of speak­er 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 identi­cally. Push down on the button below the terminal and insert the wire, or the banana plug, through the hole (see Fig. 3).
POWER HANDLING
Thanks to its high efficiency, the JBL SC305 loudspeaker will produce reason­able volume levels in a room of moderate size with very little amplifier power. 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 spe­cific loudspeaker model. Please see the specification section for details. Following these guidelines will provide virtually distor­tion-free sound reproduction and long loud­speaker life.
TROUBLESHOOTING
The vast majority of new speaker "malfunc­tions" end up being traced to connections or switch settings. Check the following tips first, before requesting service.
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 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
mal listening position
at your nor-
, as the sound
from the left and right front speakers.
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.
4. AV receiver/amp "audio direct" switch is activated. This switch should be off to acti­vate the 5 speaker surround mode.
5. Sound source (VDP, VCR,CD,cassette deck, turntable) not turned on, not activat­ed, not hooked up or not selected on AV receiver/amp front panel.
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
GENERAL CARE
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.
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.
SERVICE
Should your loudspeaker ever need ser­vice, return it to the JBL dealer from whom it was purchased. If for some reason this is impractical, in the United States, call 800­336-4JBL 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 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 with­out prior authorization.
Specifications SC305
High Frequency Dome Transducer 14mm Titanium Laminate Low Frequency (High Polymer Laminate) 5"(2) Crossover Frequency 2.7 kHz Frequency Response (- 6 dB) 100 Hz to20 kHz Sensitivity(1 Watt/1 meter) 87 dB Nominal Impedance 8 ohms Recommended Amplifier Power* 10 to 100 Watts External Dimensions (HxWxD) 7"x 20"x 6-1/2" External Dimensions (millimeters) 178x508x165 Weight (each) 15 lbs (6.8 kg) Shipping Weight 18 lbs (8.2 kg)
*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 expres­sion 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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