JBL SCL-1 High-Performance Loudspeaker



For more than 70 years, JBL has been involved in every aspect of music and film recording and reproduction, from live performances to monitoring the recordings you play in your home, car or office. We are confident that the JBL Synthesis loudspeaker you have chosen will provide every note of enjoyment that youexpect – and that when you think about purchasing additional audio equipment for your home, car or office, you will once again choose JBL. Please take a moment to register your product on our website at www.jblsynthesis.com. This enables us to keep youposted on our latest advancements, and helps us to better understand our customers and build products that meet their needs and expectations. All features and specifications are subject to change without notice.

PACKAGE CONTENTSJBL-SCL-1-High-Performance-Loudspeaker-fig-1



Positioning your loudspeakers properly is critical in order to achieve the sonic performance of a home theater. Please read the following section for guidance in correct and optimal placement.
The SCL-1 is a perfect choice to serve as front left and right main speakers in a multi-channel system. Since they have been designed for uniform coverage and maximum dispersion of sound, they should be placed with the center of the speakers at about the same height on screen as the actors to aid in the illusion that the actors’ voices are coming directly from their on-screen images. Ideally, the speakers will be placed about 60 degrees apart from each other viewed from the listening position, so that the distance between the speakers is the same as each speaker’s distance from the listener (Figure 1). The recommended mounting of the SCL-1 is vertical with the port at the top. (Figure 2).


The SCL-1 may be oriented either vertically or horizontally when used as a center channel speaker. If the speaker is being used with a perforated projection screen, it should be mounted behind the center of the screen with the horizontal center axis aligned as close as possible to the center axis of the Left and Right channel speakers (Figure 3).


NOTE: Some perforated projection screens have a batten bar or crossbar centered across the screen frame (Figure 4). In such cases make sure the bar does not block the horn. Position vertically oriented speakers so that the bar crosses in front of the speakers at the edge of the horn closest to the central woofer. Batten bar or crossbar Figure 4 If a non-perforated projection screen, LCD/plasma/OLED display is being used in the installation, the SLC-1 may be used in horizontal orientation mounted directly below or above and as close as possible to the video display (Figure 5). NOTE: It is extremely important to place the center, left and right speakers as close as possible to the same height. The horn in the center channel speaker should be no more than 2 feet (61cm) higher or lower than those in the left and right speakers. This preserves the localization integrity of “sound pans” in which the sound appears to move from left to center to right. If the program material also appears to travel up and down, it can destroy the illusion of lifelike panning effects. To mitigate the height difference between the center speaker the Left and Right channel speakers should be lowered slightly. (Figure 5).


Surround speakers should be placed in the side walls no closer to the screen than the first row of viewing chairs. If there are two rows of chairs, these speakers should be placed between the two rows. Surround speakers should be placed higher than the seating area, at least 2 feet above seated ear level (Figure 6). Notes: Please consult your authorized JBL Synthesis dealer for surround speakers’ product options


In a 7.1-channel system, two speakers are added for rear fill, in addition to the surround speakers in a 5.1-channel system. The two additional speakers are placed on or at the rear wall if used in-room. (Figure 7)


  1.  Identify all wiring connections to rear enclosure and to baffle network.
  2. Choose from the wiring options (single wire, bi-wire, bi-amp) before installation.
    To connect the Synthesis SCL-1 loudspeakers to power amplifier(s) or receiver, use two-conductor insulated speaker wire.
  • Wire length              Recommended Size
  • Up to 20 ft.               14-gauge
  • Up to 30 ft.               12-gauge
  • Greater than 30 ft    10-gauge


  •  Determine the distance between your amplifier and the most distant speaker in each group (fronts, surrounds, rear surrounds).
  • Make the hookup wires for all speakers in each group this same length, even if one speaker is much closer to your amplifier than the farthest one to maintain proper channel balance. Remember to make extra wires for biamp or bi-wire usage should you opt for either method.
  •  Run wires through walls to the mounting positions.
  •  Strip off 3/8″ of insulation from both ends of each conductor and twist each set of stranded wires into a tightly bunched spiral.
  •  Speakers and electronics terminals have corresponding positive (+) and negative (–) terminals. Most manufacturers of speakers and electronics, including JBL, Inc., use red to denote the (+) terminal and black for the (–) terminal. Please confirm before connecting.

It is important to connect all speakers identically: (+) on the speaker to (+) on the amplifier and (–) onthe speaker to (–) on the amplifier. Wiring any one speaker “out of phase” (+ to – and – to +) to other speakers in the system results in thin sound, weak bass and poor imaging. Find a visual difference between the two conductors of each pair of speaker wires. 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 part of the outer insulation. It doesn’t matter which of the two strands go to the (+) and (–) on the speakers and amplifiers, as long as all speakers are connected identically positive (+) to positive (+), negative (–) to negative (–) (Figure 8).


The SCL-1 has two sets of connectors to allow for bi-wire or bi-amp operation.

  1. Cut two pair of wires for each bi-wired speaker.
  2.  Mark both ends of the wire pairs intended for low-frequency use as “LF,” and both ends of the wire intended for high frequency use as “HF.” Then run the two sets of wire to the mounting position.
  3.  Connect “HF” labeled pair to the speaker’s “HF” input, and the “LF” labeled pair to the “LF” input. (Figure 9)
  4.  Before installing the speaker that will be bi-wired or bi-amplified, remove the two gold-plated jumper straps on the terminal cup by loosening the terminals. Store the straps away safely for future use. Be sure to tighten the terminals on the LF and HF wires. (Figure 9)
  5. Proceed to install the back box and speaker following the instructions elsewhere in this manual.CAUTION: Do not connect to your speaker in bi-wire fashion with the jumper straps attached. Severe amplifier damage, personal injury, or damage to other property may result.JBL-SCL-1-High-Performance-Loudspeaker-fig-9

An amplifier and speaker system are bi-wired when the high frequency and low frequency inputs of the speaker are driven by two different wires from the same amplifier channel. Usually different types of wire are used for the connections: a high-current-capability wire or a wire that sounds better to the user for bass is typically used for low frequencies, and a low-inductance wire or a wire that sounds better for treble to the user is used for high frequencies. Both wires are connected to the same amplifier output. Some report moderate improvement with this wiring. To bi-wire the SCL-1, connect the speaker according to the following illustration:



Bi-Amplified Wiring
An amplifier and speaker system are bi-amplified when one channel of an amplifier is used for high frequencies, and one channel of an amplifier is used for low frequencies. One 2-way speaker could use both channels from a stereo amplifier. Selecting amplifier channels and wires better suited for different bandwidths can produce noticeable improvement. To wire the SCL-1 for bi-amplification, connect the speakers according to the following illustration:




Default Setting with Built-In LF and HF Network ConnectionBypass Setting without Built-In LF and HF Network Connection.


  •  Wipe the cabinet with a clean, dry cloth to remove dust. A damp cloth may dull the cabinet’s finish. Do not use volatile liquids such as benzene, paint thinner or alcohol on the cabinet.
  •  Do not spray insecticide near the cabinet.
  •  To remove dust from the grille fabric, use a vacuum cleaner set to low suction.
  •  Do not wash the grille in water, as water may fade the grille’s color or make it uneven.
  •  If the surface of the woofer cone becomes dusty, you can carefully sweep it clean with a soft, dry calligraphy brush or paint brush. Do not use a damp cloth.



Documents / Resources

JBL SCL-1 High Performance Loudspeaker [pdf] Owner’s Manual
SCL-1, High Performance Loudspeaker

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