Jbl S4A User Manual
SYNTHESIS FOUR
S4VC, S4HC,
& S4A
FLUSH-MOUNT
LOUDSPEAKERS
OWNER
’
S AND INSTALLER
’
S
MANUAL
®
®
INTRODUCTION ......................................................................................................................................................3
I
NCLUDED.............................................................................................................................................................4
S
PEAKER PLACEMENT.............................................................................................................................................5
L
EFT AND RIGHT SPEAKERS..............................................................................................................................5
C
ENTER CHANNEL SPEAKERS ...........................................................................................................................5
A
MBIENT SURROUND SPEAKERS.......................................................................................................................6
5.1-C
HANNEL SYSTEMS..........................................................................................................................6
6.1-C
HANNEL SYSTEMS..........................................................................................................................6
7.1-C
HANNEL SYSTEMS..........................................................................................................................7
S4A M
ODES OF OPERATION ....................................................................................................................7
S4A W
IRING GUIDE...............................................................................................................................7
W
HICH DIFFUSE MODE IS THE RIGHT ONE FOR THE JOB? .............................................................................8
P
REPARING THE S4A FOR THE CORRECT OPERATIONAL MODE.........................................................................8
S4A O
RIENTATION – VERTICAL OR HORIZONTAL...........................................................................................9
S4A D
UAL DRIVE MODE.......................................................................................................................10
M
OUNTING THE SPEAKERS....................................................................................................................................10
S
PEAKER-MOUNTING OPTIONS.......................................................................................................................10
R
EQUIREMENTS FOR MOUNTING .....................................................................................................................11
C
ONNECTING THE SPEAKERS TO THE REST OF YOUR SYSTEM.......................................................................................13
P
REPARING THE HOOKUP WIRE.......................................................................................................................13
F
INE-TUNING YOUR AUDIO SYSTEM .......................................................................................................................14
A
COUSTICAL PROBLEMS IN LISTENING ROOMS ..................................................................................................14
R
OOM REFLECTIONS......................................................................................................................................14
E
XCESSIVE USE OF ABSORPTIVE MATERIALS......................................................................................................15
”S
LAP” ECHOES............................................................................................................................................16
R
ATTLES.....................................................................................................................................................17
B
ACKGROUND NOISE ....................................................................................................................................17
B
ACKGROUND-NOISE SOLUTIONS....................................................................................................................18
S
TANDING WAVES.......................................................................................................................................18
S
TANDING-WAVE SOLUTIONS: ROOM RATIOS...................................................................................................19
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TANDING-WAVE SOLUTIONS: SPEAKER PLACEMENT .........................................................................................19
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TANDING-WAVE SOLUTIONS: ABSORPTION .....................................................................................................19
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TANDING-WAVE SOLUTIONS: ROOM EQUALIZATION..........................................................................................20
T
ROUBLESHOOTING...............................................................................................................................................21
S
PECIFICATIONS...................................................................................................................................................23
CONTENTS
Congratulations on 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
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®ULTRA 2-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 S4A, 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: The midrange drivers seamlessly comple-
ment 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: The low-frequency drivers deliver
precise, undistorted bass reproduction that matches the titanium tweeter and midrange. The powerful neodymium
magnet provides its own video shielding (S4VC and S4HC), 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.
3
INTRODUCTION
or or
4
One S4HC horizontal channel
flush-mount loudspeaker
One S4VC vertical channel
flush-mount loudspeaker
One S4A multi-pole ambient
flush-mount loudspeaker
Four mounting L-brackets with
eight 1/4-20 x 3/4" screws
Eight 8-32 x 1/2" screws for
speaker installation
One grille with grille frame
INCLUDED
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 to guide you 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.
5
5.1-CHANNEL SYSTEM
Figure 1.
Figure 2.
Figure 3.
SPEAKER PLACEMENT
RCL
VIEWING
POSITION
FLOOR PLAN
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 6.1and 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 S4A multi-pole 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).
6
6.1-CHANNEL SYSTEM
Figure 5.
Figure 4.
SPEAKER PLACEMENT
Min. 2’-0"
RCL
VIEWING
POSITION
FLOOR PLAN
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).
S4A MODES OF OPERATION
The S4A multi-pole 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 reproduction.
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 the illustration of the
S4A (Figure 7) indicates, the omnidirectional woofer faces toward the listening
area, while dual sets of tweeter/midrange arrays (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 JBLSynthesis
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 2-conductor, #24 to #16 AWG wire. The relay is activated by a constant
5V to 12V DC signal.
S4A WIRING GUIDE
Each S4A speaker can be wired in single- or dual-drive mode. The best performance can be obtained by installing
four S4A speakers in a 7-channel system and wiring them in single-drive mode; that is one amplifier channel per S4A
7
7.1-CHANNEL SYSTEM
Figure 6.
Figure 8.
Single drive – Dipole or Bipole
operation only – 2-cond. speaker
wire
Dual drive – Bipole operation
only – 4-cond. speaker wire
Single drive w/Direct – Dipole or Bipole
& Direct Radiating operation – 2-cond.
speaker wire & 2-cond. trigger wire
Dual drive w/Direct – Bipole & Direct
Radiating operation – 4-cond. speaker
wire & 2-cond. trigger wire
Figure 7.
SPEAKER PLACEMENT
SIDE
LEFT
REAR LEFT
RCL
REAR RIGHT
RIGHT
SIDE
SPEAKER INPUT #1
SPEAKER INPUT #2
speaker. If only two S4A speakers can be used in a particular application, then they should be wired in dual-drive
mode so as to gain the advantages of a 7-channel system. Each S4A speaker receives amplification from 2 channels –
side and rear – which can only be accomplished in the Bipole mode.
WHICH DIFFUSE MODE IS THE RIGHT ONE FOR THE JOB?
D
IPOLE 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 S4A FOR THE CORRECT OPERATIONAL MODE
It will be necessary to choose which of the two diffuse modes to use at the
time of installation. The S4A is shipped from the factory in the Dipole mode.
If this is your choice and the speaker will be placed in the vertical orientation, no changes are required and the S4A can be directly installed into its
permanent location. For convenience, a phase switch is located on the
lower right front corner of the baffle to easily set the phase relationship to
the other surround speakers in the system (see Figure 9).
Setting the phase in relation to the other speakers in the room only applies
when the S4A speakers are set in Dipole mode.
The S4A speakers are shipped from the factory with the phase switch in the
OUT position. In this position, the positive phase array is pointing toward
8
Figure 9. Default Dipole phase relationship
Figure 10.
SPEAKER PLACEMENT
-
+
+
-
SWITCH OUT (SHIPPED) SWITCH IN (OPTIONAL)
PHASE
SWITCH
+ +
VIEWING
POSITION
– –
FLOOR PLAN
PHASE
SWITCH
RCL
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