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M9500
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System Setup
The M9500 systems are modular, each consisting of a stack of
three separate enclosures. The larger of the bass enclosures
are placed at the bottom, and the high-frequency/horn modules
stack on top and are aligned by the screws that protrude on
the bass section. The smaller bass modules are placed on top
of the high-frequency modules and are similarly aligned.
We recommend that you do not assemble the M9500 systems
until you have determined their best location in your listening
room or control room. In general, the listening angle for best
stereo imaging should be in the range from 45 to 60 degrees
and the loudspeakers should be placed no closer than about 25
or 30 cm (10" or 12") from the wall behind them. Sidewalls
s hould be s om e w hat farthe r aw ay, and the louds pe ake rs
should be toed inward toward the primary listening position.
The room itself should be quiet, well-damped, and free of
obvious flutter echoes or standing waves.
Figure 1. Electronic hookup
options; views of the rear
panel of the dividing
network. A, single full-range
amplification; B, bi-wiring
with two amplifiers; C, tri-
wiring with three amplifiers;
and D, biamplification with
external electronic dividing
network and separate high-
and low-frequency
Connect the loudspeakers to the networks using the cables
provide d. Note that the re are diffe re nt cable s for high-
fre que ncy and low -fre que ncy hookup; the y cannot be
inte rm ixe d. For pos itive contact, ins e rt the Spe akon®
connectors and turn them one-eighth turn clockwise.
amplifiers.
A
HF
Biamp
Norm
+
0
Electronic Options
–
R
Your next concern is the amplifier/ loudspeaker operating mode.
The various hookup options are shown in Figure 1. We will
describe each of these options:
HF
B
R
B
R
B
LF1
Option A, single full-range am plifier. This mode of operation
requires a relatively large, high-quality amplifier capable of
delivering up to 800 watts per channel into 4-ohms. Note that
all sections of the network are connected in parallel with the
straps provided.
Input
LF2
I
B
HF
Biamp
+
0
–
Norm
R
Option B, bi-w iring. In this mode, identical power amplifier
sections are fed full-range program; one amplifier is connected
to the high-frequency portion of the system, and the other is
fed to the low frequency sections in parallel. Many users will
us e a large s te re o am plifie r to drive the low - fre que ncy
sections and a smaller one for the high-frequency sections.
Make sure that the stereo amplifier used for the paralleled
low-frequency sections can deliver the necessary power into
4 ohms.
HF
B
R
B
R
B
LF1
LF2
Input
C
HF
Biamp
Norm
+
0
–
R
B
HF
Option C, tri-w iring. This mode of operation is similar to B,
but w ith e ach low -fre que ncy s e ction drive n by its ow n
amplifier. In this case, each low-frequency amplifier section will
look into 8 ohms.
R
B
LF1
LF2
R
B
Input
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R
D
LF1
Option D, biam plification. This mode of operation requires a
dedicated electronic dividing network crossing over aBt 650 Hz.
HF
Biamp
+
0
–
R
Norm
R
LF2
We recommend the JBL DX-1 with internal compensation
B
made for the M9500 system. If this modeInipsut used, make sure
HF
B
R
B
R
B
that the screwdriver adjustment on the back of each network
LF1
is set in the “biamp” position.
HF out
Electronic dividing
network
Input
High-fre que ncy trim s w itche s on the
back of the networks provide three set-
LF2
(650 Hz crossover)
LF out
tings (ze ro, plus , and m inus ) s o that the s ys te m s can be
trimmed for the acoustical characteristics of the listening
space.
Regardless of the operating mode you choose, we recommend
that only the finest hookup wire be used between the ampli-
fiers and dividing networks. We recommend that the wire size
be no smaller than 3.3 square millimeter cross-section (#12
AWG). The inputs to the networks can accommodate spade
lugs, pins, bare wire, or individual banana connectors.
The internal 9-volt battery that is used to bias the capacitors
will normally last at least 5 years. You may test it by pressing
the gold logo on the front of the network. If the LED on the
front of the network illuminates, the battery is functional and
need not be replaced.
Front cover
Diecast aluminum housing
The
Transducers
Figure 2. Cutaway view of
JBL 475Nd high-frequency
compression driver. Note
the curved (equalized) paths
from the diaphragm to the
driver's output.
Silver plated pole piece
Serpentine phone plug
Aquaplas-dusted
titanium diaphragm
Foam acoustic pad
Top plate
Neodymium magnet
Return circuit
Screen
Threaded mounting holes
Throat
Aluminum shorted turn
Figure 3. Cutaway view of
JBL 1400Nd low-frequency
transducer. Note both
aluminum and copper
shorting rings.
Copper shorted turn
Cooling vent (1of 3)
Neodymium magnet
Return circuit
Edgewood aluminum
ribbon voice coil
Centering spider
Diecast frame/
magnet chassis
Fiberglas/Aquaplas
composite cone
Foam compliance
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The JBL model 475Nd compression driver used in the M9500
has a smooth titanium dome 101 millimeters in diameter that
has been lightly coated with Aquaplas™ damping compound.
Its aluminum ribbon voice coil operates in a magnetic flux field
of 1.65 tesla (16,500 gauss). Mid-band efficiency is 20% , while
at the peak value of driver impedance it is in excess of 50% .
The driver uses JBL’s Coherent Wave™ phasing plug, which
provide s e qualize d path le ngths from all s e ctions of the
diaphragm to the driver's output. The driver is mounted on the
H9500 horn, a design used only in this system that provides
s m ooth loading dow n to 500 Hz and e xhibits cons is te nt
horizontal dispersion over its operating range.
There are two JBL model 1400Nd low-frequency transducers
in e ach louds pe ake r s ys te m . A s ingle 1400Nd is capable
of handling ins tantane ous input s ignals of 600 w atts ,
corresponding to a midband peak output of 118 dB Lp at a
distance of one meter. The transducer’s second and third
harmonic distortion have been reduced through the use of
JBL’s traditional aluminum shorting ring at the base of the pole
piece, as well as through the use of a copper shorting ring on
the top plate adjacent to the voice coil. The transducers make
us e of J BL’s Ve nte d Gap Cooling™ in w hich force d air,
generated by cone motion, removes heat produced by the
voice coil. Each driver is mounted in its own ported enclosure,
and the tw o e nclos ure s are “ s tagge r tune d” to provide
smoother and more extended low-frequency response.
Cutaw ay vie w s of the high-fre que ncy and low -fre que ncy
transducers are shown in Figures 2 and 3.
Typical System Perform ance Measurem ents
The high-frequency response of the M9500 system was care-
fully established by making a series of measurements over
frontal angles of 60° in both vertical and horizontal planes. This
allows for optimal listening over a wide area. The frequency
response averaged over the 60° horizontal and vertical angles,
measured from 200 Hz to 20 kHz, is shown in Figure 4. Here,
the network High Frequency trim is set in its zero position.
The s light dow nw ard tre nd w as incorporate d, bas e d on
e xte ns ive lis te ning te s ts to conte m porary pop/rock and
classical recordings.
+10
Figure 4. Averaged frontal
angle response (60°,
horizontal and vertical) of
M9500 from 200 Hz to 20
kHz.
dB
0
–10
–20
–30
1.5
2
3
4
5
6
7
8
9
2
3
4
5
6
7
8
910
100
10
1.5
2
3
4
5
6
7
8 9 10
10000
1.5
2
1000
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The directivity index (DI) of the H9500 horn is shown in Figure
5. The smoothly rising DI is a consequence of the gradual
narrowing of the vertical dispersion angle above 2 kHz and
contribute s to the ove rall flatne s s of the high-fre que ncy
response of the system.
20
100
Figure 5. Plot directivity
index (DI) and directivity
factor (Q) of the H9500.
10
0
10
1
20
50
100
200
500
1000
2000
5000
10000 20000
Frequency (Hz)
Overall system on-axis pressure response and impedance are
shown in Figure 6. The contributions of the paralleled low-
frequency sections and the high-frequency section are shown
individually along with their acoustical summation. The overall
slopes in the crossover region are a combination of electrical
(network) and acoustical response.
M9500
4.3V @ 1.5 m
HF @ "0"
Figure 6. On-axis response
of M9500. Individual
100dB
Anecmoil
contributions of paralleled
low-frequency transducers
and high-frequency section
are shown, along with their
summation. The impedance
curve is also given, showing
a minimum value of 3 ohms
in the 100 Hz range.
Ground
Plane
10 Ω
1.5
2
3
4
5
6
7
8
9
10
1000
2
3
4
5
6
7 8 910
100
1.5
2
3
4
5
6
7
8 910
10000
1.5
2
The second and third harmonic distortion of the system is
shown in Figure 7. Here, the system is driven with sine wave
input to produce an output of 96 dB Lp at a distance of 1
meter. An output of 96 dB with a sine wave input corresponds
to extremely high system output with wide band program
material. Distortion curves have been raised 20 dB, and the val-
ues seen here lie well below 1% for the lowest frequencies up
to 4.5 khz, reaching a value of only 1.6% at 10 kHz. Not many
loudspeakers can demonstrate such low levels of distortion as
shown here.
Figure 7. Second and third
harmonic distortion for
fundamental of 96 dB Lp at
a distance of 1 meter.
96dB
Distortion Raised 20dB
Solid = Second Harm.
Dash = Third Harm.
M9500
Distortion
3.0V @ 1 m
(Distortion raised 20 dB)
1.5
2
3
4
5
6
7
8
9
1000
2
3
4
5
6
7 8 910
100
10
1.5
2
3
4
5
6
7
8 910
10000
1.5
2
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Care and Maintenance of the System
Your M9500 monitors should give years of trouble-free service.
Normally, the only routine maintenance will be cleaning. The
grilles may be cleaned of dust gently with a vacuum cleaner
using a brush attachment. If there should be stains on the
grille, a soft bristle brush moistened with a dilute mixture of
water and dishwashing detergent may be used. The same
mixture may be used for cleaning the enclosure finish itself
if it has become smudged.
As mentioned before, the 9-volt batteries in the dividing net-
works will last perhaps as long as their normal shelf life. You
may expect them to last at least 5 years. If the LED no longer
lights, remove the acrylic door on the front of the network and
replace them.
System Specifications
Acoustic and Electrical Specifications:
Sensitivity:
95 dB for 2.83 V @ 1 meter
Rated Impedance (LF parallel):4 Ohms
Minimum Impedance:
Frequency Response:
Crossover Frequency:
System Polarity:
3.0 Ohms @ 100 Hz
35 Hz to 20 kHz (half space)
650 Hz
EIA (positive voltage to red terminal
produced outward cone motion)
System Com ponents and Physical Specifications:
Low-Frequency Transducer: 1400 Nd
High-Frequency Transducer: 475 Nd
Horn Assembly:
H9500
N9500
Dividing Network:
Enclosure Volumes:
78 liters (2.8 cu ft) 35 Hz tuning (upper LF)
115 liters (4.1 cu ft) 28 Hz tuning (lower LF)
System Dimensions:
140 mm H x 330 mm W x 403 mm D
(55"H x 15.13"W x 15.88"D)
Total depth including horn 521 mm (20.5")
Weight:
38.2 kg (84 lbs) upper LF
54.5 kg (120 lbs) lower LF
37.3 kg (82 lbs) horn assembly
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JBL continually strives to improve its products. New materials, produc-
tion methods and design refinements are introduced into existing
models without notice as a routine expression of our design philosophy.
For this reason, JBL M9500 Series Loudspeakers may differ in some
respect from their published specifications and descriptions, but will
always equal or exceed the original specifications unless otherwise
stated.
JBL Consumer Products, Inc.
80 Crossways Park West
Woodbury, NY 11797
8500 Balboa Blvd.
Northridge, CA 91329
800 645 7484
Printed in USA on recycled paper 9/95
Part No. JBLM9500M
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