3
INSTALLATION AND OPERATION
inputs of the power amplifiers with a minimum run of
cable.
Wire the outputs to the respective inputs of each power
amplifier making sure the LF outputs arrive at the LF
amplifier inputs. Mixing the LF, MF, and HF signals
can cause damage to the drivers.
Wire each stereo processor channel to its respective
input at the TCX924. All connections are made to the
Phoenix brand connector on the back of the chassis.
Keep all wiring from this connector away from the AC
lines and speaker output lines from the power amplifi-
ers.
The TCX924 has unbalanced outputs. Wire the inputs of
the power amplifiers for this mode.
Allow ventilation space for the electronic crossover. It
is not good practice to wedge the crossover between
two power amplifiers without the vent panels separating
the units.
SECTION 3
CALIBRATION
Remove the front security cover with the allen wrench
provided with the product.
Make sure the power switch is in the ON position. The
OFF position is also the bypass mode that allows the
audio signals from each channel to pass to the amplifi-
ers. A special protection circuit is included in the
bypass circuits to protect the MF and HF drivers from
damage from low frequency energy. The LF woofers
will receive full range audio when the TCX924 is in the
bypass mode. This is not a problem because the
woofers will not reproduce HF audio very well.
With pink noise playing adjust the MF and HF level
controls for the smoothest crossover while observing the
response on the real time analyzer set up to monitor the
auditorium. The levels should be set to match at the
crossover frequencies of 300 Hz and 2.5 kHz. Do not
be concerned with the level of the other parts of the
audio spectrum at this time.
With a ruler, measure the distance from the point where
the voice coil of the woofer is to the voice coil/dia-
phragm of the MF driver. This is the acoustic difference
between the two components. Also measure the dis-
tance between the coil/diaphragms of the MF driver
and the HF driver. The TCX924 is configured so that the
HF and LF may be positioned behind the MF driver.
Refer to the following CROSSOVER DELAY chart to
determine the best setting of the jumper “shunts” for
each channel and each delay of the TCX924 (See figure
3 for diagram of front panel shunt positions). You may
wish to reposition the mechanical alignment of the
horn/HF driver before securing it to the enclosure for an
even multiple of 2.5". For example, if the horn/HF
driver is 11 inches behind the MF woofer voice coil,
slide the HF assembly back 1.5 inch so that it is an
even 12.5 inches difference. Secure the horn/HF driver
assembly to the main enclosure.
CROSSOVER DELAY
2.5 kHz High Frequency Delay
Position
Acoustic Distance
1
0"
2
2.5"
3
5"
4
7.5"
5
10"
6
12.5"
300 Hz Low Frequency Delay
Position
Acoustic Distance
1
0"
2
6"
3
12"
4
18"
5
24"
6
30"
Some manufacturers of cinema loudspeaker stage
systems recommend reversing the HF driver connec-
tions when using a 24 dB 4-pole filter crossover. Ob-
serve your real time analyzer response to determine the
best wiring scheme.
All channels should be set to the same time correction
setting when using identical model speakers.
Leave the security cover off the TCX924 until you have
completed your room equalization. This will allow you
to make minor adjustments to the HF level setting as
you continue to tune for the flattest response.
Figure 3. Front Panel LOW and HI delay positions and MID and
HI level control. NOTE: A jumper must be installed in one of the
six delay positions or no sound will reach the output.
