JL Audio HD750/1 Owner's Manual page 19

the nine-step Procedure
1) Disconnect the Speaker Connector Plug.
2) Turn off all processing on the source unit
(bass/treble, loudness, EQ, etc.). Set fader
control to center position and subwoofer
level control to 3/4 of maximum (if
used to drive the HD750/1). Disconnect
the HD-RLC Remote Level Control
temporarily (if one is being used).
3) Switch the "Input Voltage" to "Low" and turn
the "Input Sens." control all the way down.
4) Set the source unit volume to 3/4 of full
volume. If the amplifier is being driven by a
source unit's dedicated subwoofer output, also
adjust the source unit's subwoofer level control
to 3/4 of maximum output. This will allow for
reasonable gain overlap with moderate clipping
at full volume.
5) Using the chart below, determine the
target voltage for input sensitivity
adjustment according to the nominal
impedance of the speaker system
connected to each set of outputs.
nom.
impedance
8Ω
6Ω
4Ω
3Ω
2Ω
1.5Ω
Hd 750/1
(mono)
54.8 V
54.8 V
54.8 V
47.4 V
38.7 V
33.5 V
6) Verify that you have disconnected the Speaker
Connector Plug before proceeding. Play a
track with an appropriate sine wave (within
the frequency range to be amplified by each
set of channels) at 3/4 source unit volume.
7) Connect the AC voltmeter to the Speaker
Output contacts of the amplifier.
8) Increase the "Input Sens." control until the
target voltage is delivered. If excessive voltage
is read with the control at minimum (full
counterclockwise), switch the "Input Voltage"
switch to "High" and re-adjust.
9) Once you have adjusted the amplifier to its
maximum unclipped output level, reconnect
the speaker(s). The "Input Sens." controls can
now be adjusted downward if the HD750/1
requires attenuation to achieve the desired
system balance.
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