JBL SYNTHESIS FOUR S4Ai Owner'S And Installer'S Manual Download Page 6

N

OTE

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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. 

A

MBIENT

S

URROUND

S

PEAKERS

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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-C

HANNEL

S

YSTEMS

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-C

HANNEL

S

YSTEMS

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).

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R

C

L

FLOOR PLAN

Figure 5. 6.1-Channel system

M

in

.2

'-0

"

Figure 4.

S

PEAKER

P

LACEMENT

Summary of Contents for SYNTHESIS FOUR S4Ai

Page 1: ...SYNTHESIS FOUR S4VC S4HC S4Ai FLUSH MOUNT LOUDSPEAKERS OWNER S AND INSTALLER S MANUAL...

Page 2: ...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 AC...

Page 3: ...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 INV...

Page 4: ...speaker One S4VC vertical channel flush mount loudspeaker One S4Ai multipole 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...

Page 5: ...ge 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...

Page 6: ...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 ba...

Page 7: ...r 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 conducto...

Page 8: ...on 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...

Page 9: ...s being installed in a ceiling and the joists are running from front to back in the room In that situation conventional in wall side channels would be firing side to side rather than front to back To...

Page 10: ...ng to the right rather than the left MOUNTING THE SPEAKERS SPEAKER MOUNTING OPTIONS The S4VC S4HC and S4Ai models all use the same mounting bracket There are two models to choose from based on the typ...

Page 11: ...to the wall surface REQUIREMENTS FOR MOUNTING OPTION 1 NEW CONSTRUCTION The S4PCB mounting flange bracket must be installed before the drywall is installed in the room Attach the included L brackets...

Page 12: ...any type of mounting bracket other than the S4PCB the S4RFB or any other bracket that JBL may supply for these speakers in the future Drilling holes in the product or improperly installing mounting b...

Page 13: ...te the terminal and black for the terminal although some electronics manufacturers have adopted the new color coding standard promulgated by the Consumer Electronics Association In that case the posit...

Page 14: ...r system s sound reproduction ROOM REFLECTIONS The most troublesome room reflections are usually the early reflections of the front LCR speakers off the floor ceiling and side walls These reflections...

Page 15: ...ions It is important that the cloth be acoustically transparent however or the effectiveness of the absorptive material will be greatly reduced The simplest test for this is to hold a large sample of...

Page 16: ...playback system to create the environment rather than having the room s native acoustic signature color everything The solution for slap echoes is usually a combination of absorption and diffusion Sp...

Page 17: ...tem should be subjected to the rattle test at least once the difference in low level resolution and in freedom from pseudodistortion is sometimes large while the effort involved is quite small BACKGRO...

Page 18: ...with fiberglass this also can enhance the perceived bass since the subwoofers may cause structural vibrations through the false floor that can then be transmitted up through furniture Seal all window...

Page 19: ...oofer placement Leave yourself some latitude with regard to subwoofer placement when plan ning your system the final adjustment will probably have to be done on something of a trial and error basis Se...

Page 20: ...ze the various room modes and recommend appropriate action This will sometimes take the form of a custom designed bass trap which may be easily con structed But it takes specific skills to determine i...

Page 21: ...Digital or DTS mode make correctly sure that the receiver processor is configured so that the speaker in question is enabled Center speaker is configured In Dolby Pro Logic mode make sure the incorrec...

Page 22: ...ze early reflections Aim speakers at listening area Poor program source Check another program source Improper polarity Check polarity of wire connections Indistinct dialogue Slap echoes Add absorption...

Page 23: ...shielded aluminum baskets High Frequency 1 25mm Pure titanium 1 25mm Pure titanium Triple 1 25mm pure titanium Transducer s dome with rubber surround dome with rubber surround dome with rubber surrou...

Page 24: ...1 11 05 Declaration of Conformity We Harman Consumer Group International 2 route de Tours 72500 Ch teau du Loir France declare in own responsibility that the products described in this owner s manual...

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