JBL M9500 User Manual

Page 4

Option D, biamplification. This mode of operation requires a
dedicated electronic dividing network crossing over at 650 Hz.
We recommend the JBL DX-1 with internal compensation
made for the M9500 system. If this mode is used, make sure
that the screwdriver adjustment on the back of each network
is set in the “biamp” position.

High-frequency trim switches on the
back of the networks provide three set-
tings (zero, plus, and minus) so that the systems 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.

The
Transducers

LF1

LF2

Input

To M950

LF1

LF2

Input

Biamp

Norm

–

To M9500

HF out

LF out

Electronic dividing

network

(650 Hz crossover)

,,,

,,,,,

,,,

Silver plated pole piece

Front cover

Diecast aluminum housing

Serpentine phone plug

Aquaplas-dusted

titanium diaphragm

Foam acoustic pad

Top plate

Neodymium magnet

Return circuit

Screen

Throat

Threaded mounting holes

,,,,

,,,

,,,,

,,,

,,,,,,

,,,

Aluminum shorted turn

Copper shorted turn

Cooling vent (1 of 3)

Neodymium magnet

Return circuit

Edgewood aluminum

ribbon voice coil

Centering spider

Diecast frame/

magnet chassis

Fiberglas/Aquaplas

composite cone

Foam compliance

Figure 2. Cutaway view of
JBL 475Nd high-frequency
compression driver. Note
the curved (equalized) paths
from the diaphragm to the
driver's output.

Figure 3. Cutaway view of
JBL 1400Nd low-frequency
transducer. Note both
aluminum and copper
shorting rings.

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