JBL M9500 - Manual (Page 3)

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 high-
frequency 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.
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
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
amplifiers.
Version 9/14/95 7/27/98 2:58 PM Page 3