JBL M9500 User Manual
M9500 MONITOR LOUDSPEAKERS
OWNERS MANUAL
M9500
GENERAL SYSTEM DESCRIPTION
The JBL M9500 monitor loudspeaker system represents a
refinement of the principles that have guided JBL’s high-level
monitor system design over the last thirty years.
In keeping with contemporary monitoring practice, the system
is essentially of two-way design. A horn-compression driver
section covers the frequency range from 650Hz to20kHz.
Located above and below the high-frequency section are
mirror-imaged low-frequency transducers in ported enclosures.
The stereo pair of loudspeakers exhibits both vertical and
horizontal symmetry for effective “point source” radiation and
for accurate stereophonic imaging. All transducers make use of
shielded neodymium magnets, and the systems can be used in
proximity to video monitors with no interference.
The M9500 system uses stand-alone dividing networks that
facilitate various electronic options, including bi-wiring, triwiring, and biamplification. The networks are designed around
the finest components available and make use of dc bias on
the capacitors for greater linearity.
A single M9500 system is capable of producing sine wave output levels of 110 dB Lp at one meter with extremely low
distortion. In terms of wide band program, this translates into
levels of 120 dB Lp for the stereo pair at normal listening
distances of 2 and 3 meters.
The enclosures are made of thick sections of mediumdensity fiberboard, liberally braced, and have an attractive,
scuff-resistant finish.
Unpacking and Inspection
The complete M9500 system is shipped in eight containers, as
detailed below:
2 — Lower low-frequency enclosures
2 — High-frequency/horn enclosures
2 — Upper low-frequency enclosures
1 — Dividing networks (2 networks in one package,
including 6 hook-up cables and 4 9-volt batteries)
1 — Low-frequency grilles
(4 in one package)
Make sure that you have all containers. Unpack them carefully
and inform your JBL dealer of any sign of damage. It is
recommended that you save the packaging for future use.
A
HF
HF
LF1
LF2
R
0
B
R
B
R
Input
Biamp
Norm
B
+
–
To M9500
I
B
HF
HF
LF1
LF2
R
0
B
R
B
R
Input
Biamp
Norm
B
+
–
To M9500
C
HF
HF
LF1
LF2
R
0
B
R
B
R
Input
Biamp
Norm
B
+
–
To M9500
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
should be somewhat farther away, and the loudspeakers
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.
Connect the loudspeakers to the networks using the cables
provided. Note that there are different cables for highfrequency and low-frequency hookup; they cannot be
intermixed. For positive contact, insert the Speakon
connectors and turn them one-eighth turn clockwise.
Electronic Options
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:
Option A, single full-range amplifier. 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.
Option B, bi-wiring. 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
use a large stereo amplifier to drive the low- frequency
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.
Option C, tri-wiring. This mode of operation is similar to B,
but with each low-frequency section driven by its own
amplifier. In this case, each low-frequency amplifier section will
look into 8 ohms.
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, triwiring with three amplifiers;
and D, biamplification with
external electronic dividing
®
network and separate highand low-frequency
amplifiers.
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