Owner's Manual

APPENDIX A:
Input Sensitivity Level Setting
Following the directions below will allow the
installer to adjust the input sensitivity ofeach
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
o 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 offall processing (bass/treble, loudness,
EQ, etc.) on the source unit, processors (if
used) and amplifier. Set fader control to center
position
and subwoofer level control to 3/4 of
maximum (if used to feed the M4300).
3) Switch
the "Input Voltage" switch to "Low"
and turn the "Input Sens." control all the
way down.
4) Set the source unit volume to 3/4 offull
volume. This will allow for reasonable gain
overlap with moderate clipping at full volume.
S) Using the chart on this page, determine the target
voltage
for input sensitivity adjustment according
to the nominal impedance ofthe speaker system
connected
to the amplifier outputs.
6) Verify that you have disconnected the speakers
before proceeding. Playa track with an
appropriate sine wave (within the frequency
range to be amplified by the M4300) at 3/4
source unit volume.
7) Connect the AC voltmeter to the speaker output
connectors ofthe amplifier.
If the channel
pair
is operating in stereo, it is only necessary
to measure one channel. Ifbridged, make sure
you test the voltage at the correct connectors
(L+ and R-).
14
8) Increase the "Input Sens." control until the
target voltage
is observed with the voltmeter.
9) Once you have adjusted the M4300 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.
DIMPORTANTI
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." for the affected channels 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 'vvill not
require re-adjustment.
Nom.~
Impedance~
SO
13AV 26.8 V
60
13AV
25.6V
40
13AV 24.6 V
30
12.8V not recommended
20
12.3 V not recommended
..JL AUDIO M4300