JBL S4VC, S4HC &S4Ai, S4HC, S4Ai User Manual

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SYNTHESIS® FOUR

S4VC, S4HC

& S4Ai

FLUSH-MOUNT

LOUDSPEAKERS

OWNERS AND INSTALLERS

MANUAL

CONTENTS

INTRODUCTION ......................................................................................................................................................

3

INCLUDED .............................................................................................................................................................

4

SPEAKER PLACEMENT .............................................................................................................................................

5

LEFT AND RIGHT SPEAKERS..............................................................................................................................

5

CENTER CHANNEL SPEAKERS ...........................................................................................................................

5

AMBIENT SURROUND SPEAKERS .......................................................................................................................

6

5.1-CHANNEL SYSTEMS ..........................................................................................................................

6

6.1-CHANNEL SYSTEMS ..........................................................................................................................

6

7.1-CHANNEL SYSTEMS ..........................................................................................................................

7

S4Ai MODES OF OPERATION ...................................................................................................................

7

S4Ai WIRING GUIDE ..............................................................................................................................

7

WHICH DIFFUSE MODE IS THE RIGHT ONE FOR THE JOB? .............................................................................

8

PREPARING THE S4Ai FOR THE CORRECT OPERATIONAL MODE........................................................................

8

S4Ai ORIENTATION – VERTICAL OR HORIZONTAL..........................................................................................

9

S4Ai DUAL-DRIVE MODE......................................................................................................................

10

MOUNTING THE SPEAKERS ....................................................................................................................................

10

SPEAKER-MOUNTING OPTIONS .......................................................................................................................

10

REQUIREMENTS FOR MOUNTING .....................................................................................................................

11

CONNECTING THE SPEAKERS TO THE REST OF YOUR SYSTEM.......................................................................................

13

PREPARING THE HOOKUP WIRE .......................................................................................................................

13

FINE-TUNING YOUR AUDIO SYSTEM .......................................................................................................................

14

ACOUSTICAL PROBLEMS IN LISTENING ROOMS ..................................................................................................

14

ROOM REFLECTIONS......................................................................................................................................

14

EXCESSIVE USE OF ABSORPTIVE MATERIALS......................................................................................................

15

”SLAP” ECHOES ............................................................................................................................................

16

RATTLES .....................................................................................................................................................

17

BACKGROUND NOISE ....................................................................................................................................

17

BACKGROUND-NOISE SOLUTIONS ....................................................................................................................

18

STANDING WAVES .......................................................................................................................................

18

STANDING-WAVE SOLUTIONS: ROOM RATIOS ...................................................................................................

19

STANDING-WAVE SOLUTIONS: SPEAKER PLACEMENT .........................................................................................

19

STANDING-WAVE SOLUTIONS: ABSORPTION .....................................................................................................

19

STANDING-WAVE SOLUTIONS: ROOM EQUALIZATION ..........................................................................................

20

TROUBLESHOOTING...............................................................................................................................................

21

SPECIFICATIONS ...................................................................................................................................................

23

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 sixty years of preeminence in the field. They set new benchmarks in the use of “high technology” and provide you with the experience of being in the world’s greatest movie houses and concert halls – right at home! JBL Synthesis Four speaker systems feature the following:

THX ULTRA2-LICENSED HOME AUDIO SYSTEM: When used with a THX® controller and amplifiers, your speaker system will deliver a state-of-the-art THX home theater experience to your living room. You will hear in your home exactly what the director and sound engineer heard in the recording studio. The system will reproduce the audio flawlessly and without distortion.

FLUSH-MOUNT APPEARANCE: The S4Ai, S4VC and S4HC are designed to fit flush to your wall surface. Designers and interior decorators will be pleased by their hidden appearance and stunning performance.

PURE-TITANIUM, HIGH-FREQUENCY TRANSDUCER DOME: The pure-titanium diaphragms with neodymium magnet structures are ultralight to accurately reproduce lightning-fast sounds – such as cymbal crashes – yet extremely rigid to eliminate distortion and ear fatigue.

ELLIPTICAL OBLATE SPHEROIDAL(EOS) WAVEGUIDE: First developed for our JBL Professional LSR studio monitors, this unique structure enables Synthesis Four Series speakers to evenly disperse high frequencies, creating precise imaging over a wide listening area.

PURE-TITANIUM, INVERTED-DOME, MIDRANGE TRANSDUCERS (S4VC, S4HC): The midrange drivers seamlessly complement the titanium-dome tweeter and offer nearly perfect pistonic motion, which eliminates the uncontrollable flexing found in conventional cones. The inverted dome is driven precisely at its center, which cancels resonances inherent in cone materials. The result is ruler-flat frequency response beyond the crossover point.

TITANIUM-ALLOY, INVERTED-DOME, LOW-FREQUENCY TRANSDUCERS (S4VC, S4HC): The low-fre- quency drivers deliver precise, undistorted bass reproduction that matches the titanium tweeter and midrange. The powerful neodymium magnet provides its own video shielding, allowing for flexible placement near video monitors.

Cast-aluminum frames remain rigid even at the highest volumes, avoiding the distortion found in some other speaker designs. The aluminum doesn’t affect the magnetic field, so driver movement is precise.

COMMON VOICING: Synthesis Four uses common voicing across the front three channels. Since identical drivers are used, each speaker has the same tonal qualities; thus, as a sound is panned from one side to the other, there will be no change in timbre.

MAGNETIC SHIELDING: All front speakers are magnetically shielded, allowing you to place them near video monitors without generating interference or distorting the picture. (S4Ai is not magnetically shielded.)

3

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

SPEAKER PLACEMENT

Positioning your loudspeakers properly is critical in order to achieve the 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 front left and right main speakers.

Since the left and right speakers have been designed for maximum localization of sound, they should be placed with the center of the speakers at about the same height on screen as the actors would be, to aid in the illusion that the actors’ voices are coming directly from their on-screen images. Ideally, the speakers will be placed about 45 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 (see Figure 1).

CENTER CHANNEL SPEAKERS

S4VC: If you have purchased the vertical channel speaker (model S4VC) for the center position, be sure to place it vertically during installation in order to take advantage of its sound-dispersion characteristics. If you mount it horizontally, it will not provide the correct dispersion pattern. If the speaker is being used with a perforated projection screen, it should be mounted behind the center of the screen (see Figure 2). If a nonperforated projection screen, plasma display or other fixed video device is being used in the installation, the preferred center speaker is the model S4HC (below).

S4HC: If you have purchased the horizontal channel speaker (model S4HC) for the center position, be sure to position it horizontally during installation in order to take advantage of its sound-dispersion characteristics. If you mount it vertically, it will not provide the correct dispersion pattern. Although the preferred speaker model to be used with a perforated projection screen is the vertical model S4VC (above), the S4HC horizontal speaker may be used instead and should be mounted behind the center of the screen. If a nonperforated projection screen, plasma display or other fixed video device is being used in the installation, then the recommended location is directly below and as close as possible to the video display

(see Figure 3), although the inverse of this method will work also.

L C R

VIEWING

POSITION

FLOOR PLAN

Figure 1. 5.1-Channel system

Figure 2.

Figure 3.

5

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, it can destroy the illusion of panning effects and so should be avoided.

AMBIENT SURROUND SPEAKERS: Although it has been common for many years to use a number of surround speakers in commercial movie houses, until recently, the traditional home theater configuration called for 5.1 channels, i.e., front left, center, front right, surround left and surround right, plus a low-frequency-effects channel. The newer surround formats that are appearing in consumer audio equipment are calling for more complicated 6.1- and 7.1-channel systems. The advantages of using additional speakers are many. Additional channels enable a more versatile use of directionality for a more accurate surround presentation. Also, a higher overall sound-pressure level can be achieved with less energy expenditure from any individual speaker.

Placement of the surround speakers remains critical.

5.1-CHANNEL SYSTEMS

The S4Ai multipole ambient surround speakers work optimally if they are placed as far back from the screen as the viewing chairs are. If there are two rows of chairs, these speakers should be placed between them.

The ambient surround speakers should be placed higher than the seating area, at least two feet above (seated) ear level (see Figure 4).

The preferred method to mount the ambient surrounds is to put them directly in the side walls. This lets each speaker radiate to the front and back of the room and to reflect off the side walls.

There are a few instances in which the ambient surrounds would perform better if mounted in the ceiling rather than the walls. If one or both of the walls are “acoustically dead,”due to the presence of windows, fabric, furniture or other absorption, it may be necessary to turn the ambient speakers sideways and, instead of mounting them in a vertical orientation, mount them in the ceiling in a horizontal orientation.

6.1-CHANNEL SYSTEMS

A 6.1-channel system can be thought of as a 5.1-channel system with the addition of a rear center speaker placed midway between the two surround speakers, and further to the rear than the surrounds. It should be placed at the same height as the side surround speakers (see Figure 5).

Min. 2'-0"

Figure 4.

L C R

FLOOR PLAN

Figure 5. 6.1-Channel system

6

SPEAKER PLACEMENT

7.1-CHANNEL SYSTEMS

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 the rear wall or near the rear wall in the ceiling (see Figure 6).

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 for cinema reproduction, and Direct Radiating for music. Both Dipole and Bipole modes are diffusive, meaning there is less energy on-axis than off-axis relative to the front of the speaker baffle. As Figure 7 indicates, the S4Ai’s omnidirectional woofer faces toward the listening area, while dual sets of tweeter/ midrange (diffuse) arrays face toward the front and rear or from side to side in

the room. In Dipole mode the arrays play out of phase in relation to each other, and in Bipole mode they play in phase with each other.

To activate the Direct Radiating mode for music playback, use the JBL Synthesis electronics package, including the SDP-40 surround processor, to trigger the autoswitching relay in the loudspeakers. The input to the trigger connection is located at the bottom of the speaker, next to the speaker terminals (see Figure 8) and accepts two-conductor, #24 to #16 AWG wire. The relay is activated by a constant 12V DC signal.

S4Ai WIRING GUIDE

Single-drive – Dipole or Bipole operation only – two-cond. speaker wire

Figure 8.

 

Dual-drive – Bipole operation

SPEAKER INPUT #2

only – four-cond. speaker wire

SPEAKER INPUT #1

L C R

SIDE

SIDE

LEFT

RIGHT

REAR LEFT REAR RIGHT

Figure 6. 7.1-Channel system

Figure 7.

Single-drive w/Direct – Dipole or Bipole and Direct Radiating operation – two-cond. speaker wire and two-cond. trigger wire

Dual-drive w/Direct – Bipole and Direct Radiating operation – four-cond. speaker wire and two-cond. trigger wire

Each S4Ai speaker can be wired in singleor dual-drive mode. The best performance can be obtained by installing four S4Ai speakers in a 7-channel system and wiring them in single-drive mode; that is one amplifier channel per S4Ai speaker. If only two S4Ai speakers can be used in a particular application, then they should be wired in dualdrive mode so as to gain the advantages of a 7-channel system. Each S4Ai speaker receives amplification from two channels – side and rear – which can only be accomplished in the Bipole mode.

7

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 channels in a dual-drive configuration.

The speaker is located relatively far away from the listening position.

Multiple side or rear speakers are being used in a large listening room.

The speaker is mounted in a corner, at a 45-degree angle.

PREPARING THE S4Ai FOR THE CORRECT

OPERATIONAL MODE

-

+

+

-

PHASE

PHASE

SWITCH

SWITCH

SWITCH OUT (SHIPPED)

SWITCH IN (OPTIONAL)

Figure 9. Dipole phase relationship

It will be necessary to choose which of the two diffuse modes to use at the time of installation. The S4Ai is shipped from the factory in the Bipole mode. If this is your choice and the speaker will be placed in the vertical orientation, no changes are required and the S4Ai can be directly installed into its permanent location.

Setting the phase in relation to the other speakers in the room only applies when the S4Ai speakers are set in Dipole mode. If you choose to use the S4Ai in Dipole mode, the following information for proper phase relations between speakers will apply:

The S4Ai speakers are shipped from the factory with the phase switch in the OUT position. In this position, the positive phase array is pointing toward the left as you face the speaker. That is, when positive voltage is applied to the cone, the cone will move outward. Usually, when the Dipole mode is used in a 5.1 system, the positive phase array should fire toward the front of the room. The array facing the rear of the room will have a negative orientation. That is, when positive voltage is applied to the cone, it will move inward, in the opposite direction of the other array on the speaker. As shipped from the factory, the S4Ai is set up for placement in the right-side wall in a 5.1-channel system. The speaker that will be placed in the left-side wall should have its phase switch pushed in so that the positive phase array will be firing toward the front of the room when installed (see Figure 10).

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