4 3 4 4 M k I I
P R O F E S S I O N A L S E R I E S
L O U D S P E A K E R S Y S T E M
A NEW STANDARD FOR A NEW CENTURY
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Table of Contents
Low-Frequency Transducer
Mid-Frequency Transducer
High-Frequency Transducer
Ultrahigh-Frequency Transducer
Dividing Networks
4
5
5
5
6
Battery Replacement
Placement
7
8
Speaker Connections
Bi-Wiring
9
10
13
14
Maintenance and Service
System Specifications
Declaration of Conformity
We, JBL Europe A/S
Kongevejen 194B
DK-3460 Birkerød
DENMARK
JBL Consumer Products
declare in own responsibility, that the loudspeakers
described in this owner’s manual are in compliance with
technical standards:
80 Crossways Park West, Woodbury, NY 11797
8500 Balboa Boulevard, Northridge, CA 91329
1-800-336-4JBL (4525) (USA only)
EN 50 081-1/1992
EN 50 082-1/3.1995
©1996 JBL, Incorporated. JBL is a registered
trademark of JBL, Incorporated.
Steen Michaelsen
JBL Europe A/S
Birkerød. DENMARK. 2/97
Printed in USA 2/97
Part No. 4344MkIIOM97
A Harman International Company
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With the Professional Series 4344MkII Loudspeakers, JBL
combines the most advanced technology with a classic JBL design. These
speakers continue the longstanding tradition of precise studio monitor
sound for which JBL is famous. You will enjoy the benefits of a 2" high-
frequency compression driver, cast frame low-frequency transducers with
vented pole pieces, and JBL’s proprietary Symmetrical Field Geometry
magnet design, as well as high definition dividing networks incorporating
the highest quality electronic components available.
Low-Frequency Transducer
The 4344MkII features an all-new 15" (381mm) low-frequency
transducer developed specifically for the 4344MkII. Derived from
JBL’s legacy of highly powerful yet efficient bass drivers, this woofer
delivers full low-frequency performance with clarity and speed
unprecedented among 15" drivers. The voice coil is 4" (102mm) in
diameter and wound on edge from flat aluminum ribbon wire on a
thermoset composite™ form.
No.
4
The cone is a rigid paper composite, treated with Aquaplas™ for strength,
speed, and damping. JBL’s Symmetrical Field Geometry is employed in
the form of an aluminum sleeve around the pole piece. This sleeve reduces
second-order distortion through induced flux control. Its aluminum
composition is also a more efficient conductor of heat, so it assists in
dissipating heat away from the voice coil to extend the power capacity.
Cooling of the voice coil is further enhanced by the use of a vented pole
piece. The rigid frame is cast from aluminum alloy, an excellent
thermal conductor, which further acts to efficiently draw heat away from
the voice coil and magnet assembly. This combination of advanced design
technology results in a bass driver that is remarkably free from dynamic
restriction due to heat buildup.
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Mid-Frequency Transducer
The 4344MkII also features a 10" (254mm) mid-frequency transducer.
The voice coil is 3" (76mm) in diameter and wound on edge from flat
copper ribbon wire on a thermoset composite™ form. Its very high-power
capability and freedom from breakup make it an ideal midrange in a system
that is designed to play at high levels with absolutely no signs of distress. It
makes the transition from the woofer at 340Hz, providing excellent response
throughout the important vocal range.
High-Frequency Transducer
Throughout the history of high-frequency transducer design, the goal of
extended frequency response has been at odds with the need for high
power handling. The 4344MkII utilizes a 2" compression driver with
an Aquaplas-coated titanium dome. JBL has long chosen titanium as the
material for its highest-quality high-frequency transducers and the
4344MkII is no exception. Titanium possesses the essential requirements
for a high-frequency transducer. First, titanium is extremely light, yet
rigid. The goal is to maintain a piston-like action as high in frequency as
possible. Should the material flex easily, the diaphragm will break up into
random vibrations. Second, titanium is virtually immune to fatigue,
unaffected by the cumulative effect of millions of flexures over long
operating periods. These factors coupled with the higher power handling
that titanium affords, allow us to produce an extremely smooth high-
frequency transducer with extended frequency response that can handle all
the demands of today’s digital programs. The Horn/Lens assembly ensures
controlled distribution of the high frequencies, resulting in a wide sound-
stage with pinpoint imaging.
No.
5
ultrahigh-Frequency Transducer
For the ultrahigh-frequency transducer, we chose a 1-3/4" compression
driver with an edge-wound aluminum voice coil. This driver reproduces
all of the ultrahigh frequencies above 8000Hz with incredible clarity
and detail.
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Dividing Networks
The job of the dividing network is to distribute the various frequencies to
their respective transducers. The network is also designed to complement
component location on the baffle. Slopes are chosen to match the exact
response of each driver in its respective frequency range, as well as to
ensure that the high-frequency transducers are adequately protected from
dangerous low-frequency components.
For the 4344MkII system, we chose our Charge-Coupled Linear
Definition™ Dividing Network. The inductors are all designed for high-
current, low-distortion operation. All capacitors in the network are
series/parallel connected and operated with D.C. bias. This effectively
enables the capacitors to operate in “Class A” mode, which substantially
increases sonic detail, resolution, and dynamics. The low-frequency section
of the dividing network is mounted on a dedicated circuit board that
separates both electrical and magnetic properties from that of the
midrange and tweeter sections.
Professional Series
Model 4344MkII
Serial Number:
No.
JBL Incorporated, Northridge, CA USA
ULTRA HIGH FREQUENCY LEVEL, dB
–2.5
6
–6.5
–∞
0
Additionally, the 4344MkII’s dividing network allows for passive,
bi-wire, passive bi-amp, and full active bi-amp operation. For the full active
bi-amp mode we recommend the use of a high-quality electronic crossover.
+1.5
HIGH FREQUENCY LEVEL, dB
–2.5
–6.5
–∞
0
+1.5
MID FREQUENCY LEVEL, dB
–2.5
–6.5
–∞
0
+1.5
Level adjustments
are provided to allow
precision frequency
response contouring. The
midrange, high-frequency,
and ultrahigh-frequency
drivers may be fine-tuned
for optimum sound in any
listening room.
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Figure 1 Battery Installation
Battery Replacement
The battery should be replaced approximately every 2 years. This is
accomplished as follows:
BI-AMP
BATTERY
NORMAL/
BI-WIRE
•
Unscrew the two screws that hold the battery access cover in place. It
is located on the upper portion of the dividing network, on the rear of
the speaker enclosure (Figure 1).
JBL INCORPORATED
8500 Balboa Blvd., Northridge, CA USA
High Frequency
Low Frequency
•
•
Write today’s date, including the year, in this manual.
Install the battery by aligning the battery terminals with the mating
terminals in the network housing. Align male to female, female to
male terminals, then snap the connectors together, assuring a tight
connection.
•
Replace the battery access cover and install screws.
Battery Replacement Record
Date Installed:
No.
7
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Figure 2 Placement
Position Top View
Placement
Ideally the systems should be placed at least three feet from any walls. The
height, at the bottom of the Lens assembly, should be at ear level. The two
speakers should be equidistant from your primary listening position; the
distance should be determined by the distance between the speakers. We
recommend that the angle between the speakers, at the listening position,
be between 45° to 60°. For example, if the speakers are 8' apart, your
listening position should be 8'–12' from each speaker. To widen the area in
which the best stereo image will be perceived, turn the speaker to face the
primary listening position (Figure 2).
3'
3'
10 – 15
10 – 15
Position Front View
3'
3'
Ear level when
seated in
It is normally recommended that the 4344MkII loudspeakers be
positioned so that the ultrahigh-frequency transducers are towards the out-
side. In some listening environments, however, the imaging characteristics
may be improved by positioning the ultrahigh-frequency transducers
towards the inside. We suggest you experiment with the positioning of
your loudspeakers to determine the ideal placement in your listening room.
listening position
No.
8
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Figure 3 Connections
Speaker Connections
Bare Wire
Connecting Method
The 4344MkII loudspeakers can be connected by one of several meth-
ods. The binding posts on the rear panel of the 4344MkII will accept
most types of audio cable and connectors, including banana plugs and
bare wire (Figure 3). Follow the hookup method that best describes your
system.
TED
JBL INCORPORA
A
BLVD. NORTHRIDGE, CA US
A
8500 BALBO
HIGH FREQUENCY
LOW FREQUENCY
Standard Connections (Figure 4)
Banana/Spade
Connecting Method
1. For each channel, connect the red (+) terminal on the
4344MkII to the red (+) terminal on your amplifier.
TED
JBL INCORPORA
A
BLVD. NORTHRIDGE, CA US
A
8500 BALBO
2. For each channel, connect the black (–) terminal on the
4344MkII to the black (–) terminal on the amplifier.
HIGH FREQUENCY
LOW FREQUENCY
Connecting the systems in this manner ensures that they will operate in
phase; that is, they will work together rather than in opposition.
Connecting the speaker system out of phase will not cause damage but
will adversely affect the speaker’s sound.
No.
9
Figure 4 Standard
Connecting Method
TED
JBL INCORPORA
A
BLVD. NORTHRIDGE, CA US
A
8500 BALBO
HIGH FREQUENCY
LOW FREQUENCY
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Bi-Wiring
The 4344MkII’s outer connection panel and internal dividing
network are designed so that separate sets of speaker cable can be attached
to the low-frequency transducer and midrange/high-frequency transducer
portions of the dividing network. This is called bi-wiring. Bi-wiring can
provide several sonic advantages and considerably more flexibility in
power amplifier selection. The advantages of bi-wiring are as follows:
Reduction of Intermodulation
The majority of current flowing between an amplifier and speaker is devoted
to bass reproduction. In fact, 60% or more of an amplifier’s output is des-
tined for the woofers. When current flows through a wire, it produces an
electro-magnetic field (EMF) that expands and collapses at a rate equal to
that of the music’s complex frequency components. If a single speaker
wire must conduct the full musical frequency, the preponderance of low-
frequency information can interact with or modulate high frequencies.
The resulting intermodulation can create audible changes to the high
frequencies even before they reach the loudspeakers.
No.
10
By using separate cables for high and low frequencies, unwanted high-
frequency modulation is avoided. Low-frequency information flows
through one cable while high frequencies flow through another.
Frequency-optimized Cables
Having the opportunity to use separate low- and high-frequency cables
allows you to use cables best suited to each frequency range. Optimally,
you should use high-quality, audiophile-grade speaker cables for both low-
and high-frequency conductors. However, let your ears guide you to the
cables that best match the 4344MkII loudspeakers to your amplifier.
Amplifier Flexibility
Bi-wiring also allows you the option of using separate stereo power
amplifiers for left and right speakers, or even four mono amplifiers.
Whether you use two or four amplifiers, it is important to use the same
brand and model to power like connections on the 4344MkII.
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Figure 5 Bi-Wire Connecting Method
Bi-Wiring Connections
Figures 5 through 8 show two bi-wiring options, single-stereo amplifier
and dual-stereo amplifier modes. For passive and bi-wire connections, set
the switch to the Normal/Bi-Wire position (Figure 5a).
AMP
NORMAL/
BI-WIRE
TED
JBL INCORPORA
A
BLVD. NORTHRIDGE, CA US
A
8500 BALBO
HIGH FREQUENCY
LOW FREQUENCY
Important
1. The external “strapping bars” that normally connect the 4344MkII
low-frequency and high-frequency terminals
Figure 5a Normal/Bi-Wire Position
.
To remove the shorting straps, simply loosen and slide the bars off to the
side (Figure 8).
Bi-AMP
NORMAL/
BI-WIRE
Figure 6 One-Amp Bi-Wire
2.
Preamp
Operating two amplifier channels without removing the
strapping bars can seriously damage your amplifiers!
HF
LF
HF
LF
Stereo amp
3. If you have hooked up your 4344MkII loudspeakers in any of the
bi-wire configurations indicated, it is not advisable to use additional
speakers separately or simultaneously.
No.
11
Figure 7 Two-Amp Bi-Wire
4. As with conventional one-amplifier connections, make sure that all
speaker cables are the same length.
Preamp w/Y-corded output
HF
LF
HF
LF
Stereo amps
Figure 8 Removal of Shorting Straps
AMP
NORMAL/
BI-WIRE
TED
JBL INCORPORA
A
BLVD. NORTHRIDGE, CA US
A
8500 BALBO
HIGH FREQUENCY
LOW FREQUENCY
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Figure 9 Bi-Amp Connecting Method
Bi-Amping Connections
AMP
The optimal method of powering the 4344MkII system is with two
amplifiers, one for low frequencies and one for the mid/high frequencies.
It is necessary to use a high-quality active crossover module. Since each
amplifier only drives a limited frequency range, this method allows the
user to select amplifiers with the desired sonic character for low and
high frequencies.
NORMAL/
BI-WIRE
TED
JBL INCORPORA
A
BLVD. NORTHRIDGE, CA US
A
8500 BALBO
HIGH FREQUENCY
LOW FREQUENCY
Make sure that the input sensitivity of each of the amplifiers is the same,
or that input level controls are provided to maintain the proper low-to-
mid/high balance. If two identical stereo amplifiers are used, one may be
located near each loudspeaker to drive low- and mid/high-frequency
sections through short wire runs.
Figure 9a Bi-Amp Switch Setting
BI-AMP
BATTERY
NORMAL/
BI-WIRE
The external “strapping bars” that normally connect the 4344MkII
low-frequency and high-frequency terminals
No.
12
To remove the shorting straps, simply loosen and slide the bars off to the
side (Figure 8).
If the system is wired in the bi-amp method, set the Bi-Amp/Normal
switch to the Bi-Amp position (Figure 9 and Figure 9a).
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Maintenance and Service
The 4344MkII loudspeaker systems have an oiled finish. Cleaning
should be done with an untreated dust cloth. Do not use conventional
furniture waxes and polishes, which are not designed for oiled finishes.
If touch-up is necessary or the finish appears to be drying out, the surface
may be re-oiled with a commercially available oil-finishing preparation.
Do not use any solvents on the finish.
The grille may be gently vacuumed. Stains may be removed with an aerosol
cleaner, following the cleaner's instructions. Do not use any solvents on the
grille.
All wiring connections should be inspected and cleaned or remade
periodically. The frequency of maintenance depends on the metals involved
in the connections, atmospheric conditions, and other factors, but once per
year is the minimum. The battery should be replaced approximately every
three years. Consult your JBL dealer for specific recommendations.
No.
13
If a problem occurs, make sure that all connections are properly made and
clean. If a problem exists in one loudspeaker, reverse the speaker wires to
the left and right system. If the problem remains in the same speaker, then
the fault is with the loudspeaker. If the problem appears in the opposite
speaker, the cause is in another component or cable. In the event that your
4344MkII loudspeaker system ever needs service, contact your local
JBL dealer.
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System Specifications
Frequency Response:
30Hz – 22kHz –6dB
Sensitivity:
95dB for 2.83V @ 1 meter
Recommended Maximum
Power Handling:
200 watts continuous
800 watts peak
Nominal Impedance:
6 ohms
Crossover Frequencies:
340Hz, 1300Hz, 8000Hz
ME150H
Low-Frequency Transducer:
Mid-Frequency Transducer:
High-Frequency Transducer:
2123H
No.
275ND
14
Ultrahigh-Frequency Transducer: 2405H
Tuning Frequency of Woofer:
Dimensions (HxWxD):
32Hz
41-3/8 x 25 x 17"
1051 x 635 x 432 mm
Weight:
180 lbs
82 kg
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