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®
SYNTHESIS FOUR
S4VC, S4HC
& S4Ai
FLUSH-MOUNT
LOUDSPEAKERS
’ ’
OWNER S AND INSTALLER S
MANUAL
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CONTENTS INTRODUCTION ......................................................................................................................................................3 INCLUDED.............................................................................................................................................................4 SPEAKER PLACEMENT.............................................................................................................................................5
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INTRODUCTION ® Thank you for purchasing JBL Synthesis Four flush-mount home theater loudspeakers. These products represent the ® synthesis of everything that JBL has learned about the emotional power of audio and video in more than fifty years of preeminence in the field. They set new benchmarks in the use of “high technology” and provide you with the experi- ence of being in the world’s greatest movie houses and concert halls – right at home! JBL Synthesis Four speaker systems feature the foll
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INCLUDED or or One S4VC vertical channel One S4HC horizontal channel One S4Ai multipole ambient flush-mount loudspeaker flush-mount loudspeaker flush-mount loudspeaker Four mounting L-brackets with One grille with grille frame eight 1/4-20 x 3/4" screws Eight 8-32 x 1/2" screws for speaker installation 4
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SPEAKER PLACEMENT Positioning your loudspeakers properly is critical in order to achieve the L C R sonic performance of a home theater. Please read the following section and the “Fine-Tuning Your Audio System” section for guidance in correct and optimal placement. LEFT AND RIGHT SPEAKERS: If you have purchased a Synthesis Four Digital Home Theater System, then the model S4VC will serve as your VIEWING front left and right main speakers. POSITION Since the left and right speakers have been d
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SPEAKER PLACEMENT NOTE: It is extremely important to place the tweeter/mid-bass arrays for each of the center, left and right speakers at the same height. The EOS waveguide containing the tweeter in the center channel speaker should be no more than two feet 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
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SPEAKER PLACEMENT L C R 7.1-CHANNEL SYSTEMS In a 7.1-channel system, two speakers are added for rear fill, in addition to the sur- round speakers in a 5.1-channel system. The two additional speakers are placed on the rear wall or near the rear wall in the ceiling (see Figure 6). SIDE SIDE LEFT RIGHT S4Ai MODES OF OPERATION The S4Ai multipole ambient surround speakers feature the unique capability of being configured in any of three operational modes. Choose between Dipolar or Bipolar operation f
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+ - - + SPEAKER PLACEMENT WHICH DIFFUSE MODE IS THE RIGHT ONE FOR THE JOB? DIPOLE MODE IS TYPICALLY USED WHEN: • The speaker is located relatively close to the listening position. • Multiple side or rear speakers are being used in a small listening room. • The speaker is mounted near, but not in, a corner and will be subject to negative reflections from nearby walls. • The room is highly reflective. BIPOLE MODE IS TYPICALLY USED WHEN: • One speaker location is used to drive both side and rear
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DIPOLE BIPOLE DIPOLE BIPOLE DIPOLE BIPOLE DIPOLE BIPOLE SPEAKER PLACEMENT In a 7.1-channel system, where two L C R L C R additional S4Ai speakers may be mounted in the rear wall, the positive phase arrays for all speakers should fire toward the rear corners, as shown SIDE SIDE LEFT RIGHT SIDE SIDE in Figure 11. Thus, the side left speaker LEFT RIGHT ++ should be configured with its phase ++ switch in the IN position, and the speaker on the right should be config- FLOOR PLAN ured with its phase s
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SPEAKER PLACEMENT S4Ai DUAL-DRIVE MODE As the S4Ai has the capability of producing both side and rear fields from a single location in Bipole mode while dual-driven for cinema playback (see S4Ai Wiring Guide on page 7), some care must be taken when using the Direct-Radiating mode with the autoswitching trigger for music playback. ROTATE ARRAY CW Figure 13. Rotate top baffle for vertical or horizontal orientation Use Speaker Input #1 (see Figure 8) for the side field so that the direct-radiatin
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MOUNTING THE SPEAKERS surface, the speaker must be recessed in the wall no more than 1/4 inch. The grille pins fit directly into the speaker cabinet via receiver bushings with 15 ft/lb of tension per pin. Use the marked speaker-depth-indicator flanges (attached to the sides of the speaker baffle) to appropriately adjust the depth from the wall surface so that the baffle is recessed 1/4 inch. This will ensure that the grille will sit flush to the wall surface. REQUIREMENTS FOR MOUNTING OPTION 1
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MOUNTING THE SPEAKERS REQUIREMENTS FOR MOUNTING OPTION 2 – RETROFIT/PREEXISTING CONSTRUCTION: Use the S4RFB bracket. Mount the S4RFB to the wall surface and secure it to studs behind the wall. Attach the speaker via mounting flanges to the appropriate recessed distance. The S4VC and S4HC require a minimum 6" wall depth. The S4Ai requires a minimum 4" wall depth (see Figures 18, 19 and 20). Figure 18. Mounting the S4VC speaker using the S4RFB kit Figure 19. Mounting the S4HC speaker using the
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CONNECTING THE SPEAKERS TO THE REST OF YOUR SYSTEM To connect the Synthesis Four loudspeakers to the power amplifiers or receiver, use two-conductor insulated speaker wire. We recommend #14 AWG wire as a minimum size. Your JBL dealer can recommend suitable cables. Both the S4VC and S4HC utilize push-style friction binding posts that can accommodate up to #10 AWG stranded wire. Since the S4Ai can be configured in three different ways, be sure to run the correct number and type of wires. Refer t
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FINE-TUNING YOUR AUDIO SYSTEM ACOUSTICAL PROBLEMS IN LISTENING ROOMS A home THX audio system, such as the Synthesis Four system, addresses many of the problems common to high-quality reproduction of music or soundtracks in a home environment. For example, the dispersion pattern of the front LCR speakers minimizes the effects of floor and ceiling reflections. Still, the single most important variable in any sound system is the listening environment. Room reflections create spurious false images
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Reflected Path Reflected Path FINE-TUNING YOUR AUDIO SYSTEM However, since it is not possible to SOLUTIONS TO ROOM REFLECTIONS:
“toe-in” flush-mounted speakers, the DIFFUSION AND ABSORPTION next step is the strategic placement of absorptive materials on the side walls. Loudspeaker Loudspeaker These range from commercially avail- able fiberglass and dense foam to heavy draperies and even large, overstuffed furniture. The optimal position for these Absorptive Material Absorptive Material materia
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FINE-TUNING YOUR AUDIO SYSTEM The best arrangement of the absorptive and nonabsorptive surfaces in the room can be seen in Figure 24. Most of the room surfaces are relatively absorptive, with the notable exception of the rear wall and the highest portions of the other walls, which should be diffusive. ROOM ABSORPTION FOR HOME THEATER SYSTEMS Surround speaker Screen speaker • “Dead” zone absorbs front-speaker reflection • “Live” zone provides surround propagation Figure 24. “SLAP” ECHOES “Sla
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FINE-TUNING YOUR AUDIO SYSTEM 6 degrees and having the ceiling rise toward the rear of the room at a comparable rate will do wonders for the room’s acoustics, if the wall design is solid and the angles are clearly intentional from the outset. RATTLES Rattles in the room are structural resonances (as opposed to standing waves, which are airborne resonances) that the system may stimulate due to its broad frequency response and wide dynamic range. They are particularly prominent for sounds in the
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FINE-TUNING YOUR AUDIO SYSTEM BACKGROUND-NOISE SOLUTIONS Many sources of noise in a home environment can be addressed simply. Locating the home theater in the basement often removes it from many household noises as well as isolating it from other family members. Taking care to completely seal windows and doors can also make a significant difference in reducing outside noise. Heating and cooling systems are more challenging. Sometimes, the answer may be as simple as using a “whistle-free” diffusi
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FINE-TUNING YOUR AUDIO SYSTEM STANDING-WAVE SOLUTIONS: ROOM RATIOS SUB In new construction, the best way to minimize the audibility of standing waves is to plan for an even distribution of them, so that their effects do not “pile up” on top of each other. In this regard, the ratios of room dimensions are the critical factor. Rooms having equal dimen- sions are the worst, since the standing waves in all directions reinforce one another. Room Low Relative Pressure Low Relative Pressure dimensions
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FINE-TUNING YOUR AUDIO SYSTEM Standing-wave energy tends to be concentrated in the corners of rooms, which is why placing a subwoofer in the cor- ner tends to increase its bass output. Because of this, it is possible to break standing waves up somewhat by “break- ing up” the corner. This can be accomplished by placing a column of thick, absorptive materials in the corners (covered by acoustically transparent cloth, of course). The column ought to be at least a foot on a side, and run from floor
