JL Audio XD200/2 Car Amplifier User Manual


 
8 | JL Audio - XD200/2 Owner’s Manual
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 XD200/2 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
distortion and possible speaker failure. Correct
use of this filter can substantially increase the
longevity and fidelity of your audio system.
1) “Filter Mode” Control: The XD200/2
employs a 12dB per octave filter which can be
configured as a high-pass or low-pass filter
type, or defeated completely by way of the
three-position “Filter Mode” switch:
“Off”: Defeats the filter completely, allowing
the full range of frequencies present at the
inputs to feed the amplifier. This is useful for
systems utilizing outboard active crossovers or
requiring full-range reproduction from one or
more of the XD200/2’s channel pairs.
“LP” (Low-Pass): Configures the filter to
attenuate frequencies above the selected filter
frequency at a rate of 12dB per octave. This is
useful for connection of subwoofer(s) to the
XD200/2 in a bi-amplified system.
“HP” (High-Pass): Configures the filter to
attenuate frequencies below the selected filter
frequency at a rate of 12dB per octave. This is
useful for connection of component speakers to
the XD200/2 in a bi-amplified system.
2) “Filter Freq. (Hz)” The filter frequency
markings surrounding this rotary control
are for reference purposes and are generally
accurate to within 1/3 octave or better. If you
would like to select the filter cutoff frequency
with a higher level of precision, consult the
chart in Appendix B (page 13).
Tuning Hint: If you are using the XD200/2
to drive a subwoofer system (“LP mode), a
component satellite speaker system (“HP mode)
or both, 80 Hz is a good baseline “Filter Freq.
(Hz)” setting. After properly adjusting the “Input
Sens.”, as outlined in Appendix A (page 12), you
can fine tune the “Filter Freq. (Hz)” control to
achieve the desired system frequency response.