JL Audio 98604 XD Series Monoblock Class D 600 W Subwoofer Amplifier

User Manual - Page 12

For 98604.

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12 | JL Audio - XD600/1v2 Owners Manual
APPENDIX A:
Input Sensitivity Level Setting
Following the directions below will allow the
installer to adjust the input sensitivity of each
amplifier channel pair simply and easily in just a
few minutes using equipment which is commonly
available in installation bays.
Necessary Equipment
• Digital AC Voltmeter
CD with a sine-wave test tone recorded at
0 dB reference level in the frequency range
to be amplified for that set of channels
(50 Hz for subwoofer channels, 1 kHz for a
midrange application). Do not use attenuated
test tones (-10 dB, -20 dB, etc.).
The Nine-Step Procedure
1) Disconnect the speaker(s) from the amplifier’s
speaker output connectors.
2) Turn off all processing (bass/treble, loudness,
EQ, etc.) on the source unit, processors (if
used) and amplifier. Set the fader control to
center position and the subwoofer level control
to 3/4 of maximum (if used to feed
the XD600/1v2).
3) Switch the “Input Voltage” switch to “Low
and turn the amplifiers “Input Sens.” control
all the way down.
4) Set the source unit volume to 3/4 of full
volume. This will allow for reasonable gain
overlap with moderate clipping at full volume.
5) Using the chart on this page, determine the target
voltage for input sensitivity adjustment according
to the nominal impedance of the speaker system
connected to the amplifier outputs.
6) Verify that you have disconnected the speakers
before proceeding. Play a track with an
appropriate sine wave (within the frequency
range to be amplified by the XD600/1v2) at 3/4
source unit volume.
7) Connect the AC voltmeter to the speaker output
connectors of the amplifier. Make sure you test
the voltage at the correct connectors (+ and –).
8) Increase the Input Sens. control until the
target voltage is observed with the voltmeter.
9) Once you have adjusted the XD600/1v2 to
its maximum low-distortion output level,
reconnect the speaker(s). The Input Sens.
controls can now be adjusted downward if the
amplifier requires attenuation to achieve the
desired system balance.
Do not increase any Input Sens. setting for
any amplifier channel or channel pair in the
system beyond the maximum level established
during this procedure. Doing so will result in
audible distortion and possible speaker damage.
It will be necessary to re-adjust the
Input Sens. if any equalizer boost is activated
after setting the Input Sens. with this
procedure. This applies to any EQ boost circuit,
including source unit tone controls or EQ circuits.
EQ cuts will not require re-adjustment.
Nom. Impedance Target AC Voltage
4 40.0 V
3 38.7 V
2 34.6 V
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