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AMPLIFIER CONTROLS
1) "Input Sens.": Once the appropriate "Input
Voltage" range has been selected, the control
labeled "Input Sens." located in the "Amplifier
Controls" section can be used to match the
source unit's output voltage to the input
stage of the amplifier for maximum clean
output. Rotating the control clockwise will
result in higher sensitivity (louder for a given
input voltage). Rotating the control counter-
clockwise will result in lower sensitivity
(quieter for a given input voltage.)
Bass Boost
Input Sens.
To properly set the amplifier for maximum
clean output, please refer to Appendix A (
) in this manual. After using this procedure,
12
you can then adjust any or all "Input Sens."
levels downward if this is required to achieve
the desired system balance.
Do not increase any "Input Sens." setting
for any channel(s) of any amplifier in the
system beyond the maximum level established
during the procedure outlined in Appendix
A (page 12). Doing so will result in audible
distortion and possible speaker damage.
JL AUDIO M1700
Filter Freq. (Hz)
65
LP Filter
55
80
45
100
40
200
Filter Controls
Most speakers are not designed to reproduce
the full range of frequencies audible by the
human ear. For this reason, most speaker
systems are comprised of multiple speakers, each
dedicated to reproducing a specific frequency
range. Filters are used to select which frequency
range is sent to each section of a speaker system.
The division of frequency ranges to different
speakers can be done with passive filters (coils
and/or capacitors between the amplifier outputs
and the speakers), which are acceptable and
commonly used for filtering between mid-
range speakers and tweeters. Filtering between
subwoofer systems and satellite speaker systems
is best done with active filters, which cut off
frequency content at the input to the amplifier.
Active filters are more stable than passive filters
and do not introduce extraneous resistance,
which can degrade subwoofer performance.
The active filter built into the M1700 can be
used to eliminate potentially harmful and/or
undesired frequencies from making their way
through the amplifier sections to the speaker(s).
This serves to improve tonal balance and to avoid
page
distortion and possible speaker failure. Correct
use of these filters can substantially increase the
longevity and fidelity of your audio system.
The M1700 employs a sophisticated, variable,
low-pass active filter for its internal channel. This
feature is designed to attenuate frequencies above
its filter frequency, so that the system's subwoofers
do not reproduce any audible midrange content.
2) Filter Operation: The low-pass filter in the
M1700 is fully variable between 40 Hz and
200 Hz via the "Filter Freq." control knob
and features the ability to select between a
moderate "12dB" per octave or a steep "24dB"
per octave slope via the "Mode/Slope" switch.
Depending on the subwoofer system and
the vehicle, different slopes may be required
to produce a smooth transition to the mid-
bass speakers in the system. Experiment to
find the slope which best matches the acoustic
requirements of your system.
3) Precise Frequency Selection: The filter
7
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