JL Audio 500/1v2 owner manual Amplifier Low-Pass Filter, Input Sensitivity Adjustment Located

	Amplifier Low-Pass Filter
3) Input Sensitivity Adjustment: Located	The 500/1v2 employs a sophisticated, state-
next to the “Input Voltage” switch, in the	variable, low-pass active filter for its internal
“Amplifier Input Section”, is a rotary control	channel. This feature is designed to attenuate
labeled “Input Sens.”. Once the appropriate	frequencies above its filter frequency, so that the
“Input Voltage” range has been selected, this	system’s subwoofers do not reproduce any audible
rotary control can be used to match the source	midrange content.
unit’s output voltage to the input stage of the
amplifier for maximum clean output. Rotating	(dB)	Amp LP Filter		A
the control clockwise will result in higher	0	Mode Slope		Input V
	+13
sensitivity (louder for a given input voltage).	+15 Off 12dB 24dB			Low
Rotating the control counter-clockwise will
			65
result in lower sensitivity (quieter for a given	nced	55	80
		45	100
input voltage). To properly set the amplifier
	rol	40	200
for maximum clean output, please refer to		Filter Freq. (Hz)		Left

	Preamp Output Section
2) Precise Frequency Selection: The filter	The 500/1v2 incorporates a flexible preamp
frequency markings on the front panel of	output section, designed to make multiple
the amplifier are for reference purposes and	amplifier systems easy to set up.
are generally accurate to within 1/3 octave	The Preamp output can be configured in three
or better. If you would like to select the filter	different “Output Modes”:
frequency with a higher level of precision,
consult Appendix C: Chart A-1 (page 16)
of this manual. This chart gives you a more	Preamp Output Section
accurate frequency for each of the forty	Output Mode	Filter Slope
detented positions of the frequency selection	Full Range Amp Filter Out Filter	12dB 24dB
control. This method can be very useful if the
		65		Filter Mode
amplifier is mounted in a location where you		55	80
		45	100
can’t see the front panel markings easily.		40	200	LP HP

Left Output Right Output Filter Freq. (Hz)

Appendix A (page 14) in this manual. After
using this procedure, you can then adjust
the level of the amplifier by adjusting the	1) Filter Operation: The low-pass filter in the
input sensitivity downward, if the amplifier	500/1v2 is fully variable between 40 Hz and
requires attenuation to achieve the desired	200 Hz via the “Filter Freq.” control knob
system balance. Do not increase the “Input	and features the ability to select between a
Sens.” setting for any amplifier in the system	moderate “12dB” per octave or a steep “24dB”
beyond the maximum level established during	per octave slope via the “Mode/Slope” switch.
the procedure outlined in Appendix A (page	Depending on the subwoofer system and the
14). Doing so will result in audible distortion	vehicle, different slopes may be required to
and possible speaker damage.	produce a smooth transition to the mid-bass
	speakers in the system. Experiment to find
CROSSOVER CONTROLS	the slope which best matches the acoustic
Crossovers are groups of individual electronic	requirements of your system.
filters which allow only certain frequency
ranges to pass through them by attenuating	Tuning Hint: A trunk mounted sub whose
frequencies outside the selected range. These	output has to "fight" through a rear deck or a
filters allow the user to specify what frequency	back seat often benefits from the 12 dB/octave
range will be sent out of each channel section	slope which lets more upper bass content
of the amplifier. This, in turn, allows each	pass through. A sub that fires directly into
speaker system to only reproduce a range of	the listening environment is more likely
frequencies it is well-suited for, resulting in	to benefit from a 24 dB/octave slope.
reduced distortion and improved fidelity.
	The above hint is not “set-in-stone”…
	You should always listen to the system carefully
	to determine the best choice as vehicle acoustics
	and other factors play a big role in choosing the
	most appropriate filter slope.

3)Defeating the Amplifier Filter: The Low- Pass filter can also be defeated completely, by switching the “Mode/Slope” switch to the “Off” position. This is useful if you are using an external active crossover in the system. Keep in mind that turning the internal crossover off also defeats the “Advanced Bass Control” section processing (see page 9 for details). With the internal crossover turned off, the 500/1v2’s upper frequency response limit is

250 Hz, due to its bass-specific Class D design.

1)“Full-Range”:This is a pass-through mode for the preamp output, delivering the same signal that is being fed to the “Amplifier Input Section” (If the input signal is full-range,the preamp output will be full-range). This signal is not affected by the “Advanced Bass Control” processing selected for the amplifier.

2)“Amp Filter”: The preamp output delivers the same signal that is feeding the 500/1v2’s amplifier section, including all the processing induced by the “Amp LP Filter” and “Advanced Bass Control” sections. This is primarily used for running additional 500/1v2’s in a “Slave” configuration from the “Master” amplifier. For detailed information on

“Master/Slave” configurations, see Appendix D (page 18). If the “Output Mode” switch is in the “Amp Filter” position and the “Amp LP Filter” switch is in the “Off” position, there will be no output from the preamp output jacks. The independent output filter controls

(“Filter Slope”, “Filter Freq” and “Filter Mode”) are inactive in “Amp Filter” mode.

8 JL Audio - 500/1v2 Owner’s Manual 9