XM9 ELECTRONIC CROSSOVER NETWORK
Steep 24 dB/octave slope Crossover frequency 20 - 5000 Hz.
Outputs are always in phase Small 3.2" x 4.2" circuit board
Level controls on board Optional off board level controls
Subwoofer summing option On board RCA in/out connectors
No turn on/off transients Fourth order constant voltage design
Low noise circuit design Double sided cicuit board
The XM9 electronic crossover network module is a fourth order
constant voltage crossover design. The module provides both low-
pass and high-pass outputs. The slope of both outputs is 24
dB/octave. Because of the fourth order design the high-pass and
low-pass outputs of the crossover are always in phase with each
other. The crossover network is implemented as a fourth order
state variable filter. This filter provides both the high-pass and low-
pass function simultaneously, guaranteeing a near perfect match
of the high pass and low-pass responses.
One crossover network is needed for each channel of a bi-
amplified system. A tri-amplified system needs two networks per
channel, one to separate the high frequencies from the mid-low
frequencies and another one to separate the low and mid
frequencies. A quad system needs 3, and so on. The filter can also
be used to drive a subwoofer, where the subwoofer is shared by
the two channels of the stereo system.
The crossover frequency of the XM9 electronic crossover can
easily be changed by changing the value of four resistors. These
four resistors are mounted on an 8 pin DIP header plug for ease of
change.
Individual level controls for the high and low pass outputs are
provided with on board potentiometers. A damping control
potentiometer on the circuit board allows for adjustment of the
frequency response at the crossover frequency. A boost or cut of
up to 6 dB at the crossover frequency compensates for a dip or
bump in the response at the crossover frequency found in some
systems.
A time delay relay at the outputs of the XM9 eliminates the
transients that can happen when the unit is turned on or off. Off
board controls for the damping and the levels can also be used
with the XM9.
The XM9 electronic crossover is built on a 3.2" X 4.2" printed
circuit board of high quality glass-epoxy material. One side of the
double sided circuit board acts as a ground plane for the circuit.
This contibutes to the very high signal quality of the XM9. A silk
screen on the component side makes assembly very easy. The kit
uses only high grade components: 1% metal film resistors, 1%
matched polypropylene film capacitors for the filter capacitors,
three dual FET input and one bipolar operational amplifier.
Connectors for input, output and power make for easy assembly.
The XM9 is available as a bare board, with only the PC board and
the assembly manual; as a kit, with all needed components,
including a set of cable connectors; or completely assembled. The
frequency module consists of an 8 pin DIP header and 4 1% Metal
film resistors. The optional level/damping control potentiometer
and cable assembly can be used for mounting the level control on
a cabinet front panel. One of these XM9-PT is required for each
low-pass, high-pass and damping control.
INSTALLATION AND USE.
The typical application for the XM9 electronic cross-over filter is to
separate the high and low frequency bands in a multy-way audio
system. Figure 1 shows the application in a two-way amplifier
setup. The signal from the pre-amp is connected to the input of
the crossover. The high pass output from the cross-over is
connected to the input of the power amplfier driving the high
frequency loudspeaker tweeter), while the low pass output is
connected to the amplifier driving the low frequency speaker
woofer).
SPECIFICATIONS:
Frequency response: DC to 100 KHz, +/- 0.2 dB
Crossover frequency: 20 Hz - 5 KHz
Insertion gain: 6dB with level controls at maximum.
Filterslope: 24 dB/Octave
Harmonic distortion at 1KHz: less than 0.001%
Signal to Noise ratio: better than 110dB
Input impedance: 25 KOhm
Output load capability: 2 KOhm min.
Output impedance: 50 Ohm typ
Maximum input voltage 10 V peak-peak 4 V RMS)
Power supply requirement: dual regulated +15V and -15V @50 mA, typ
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