JL Audio Fathom f112 Owner's Manual page 16

Master level Knob
The Master Level Knob is used to control the output level of the Fathom when
the Variable Level mode is selected on the front control panel.
When rotated fully counter clockwise, the Fathom's output will be fully
muted. When at the "0" or straight up position, the Variable gain level matches
the Reference level setting. When turned fully clockwise, the Fathom's output
level is 15 dB higher than the Reference setting.
lights
The "Lights" selector switch allows the user to select one of three indicator
light modes.
"Off" turns off all of the front panel LED's at all times.
"Dim" sets all of the front panel LEDs to a low brightness level when the
Fathom is turned on.
"On" sets all of the front panel LEDs to full brightness level when the Fathom
is turned on.
IMPORTANT: WHEN TROUBLESHOOTING OR CALIBRATING THE A.R.O.
FEATURE, MAKE SURE THAT THE "LIGHTS" SWITCH IS SET TO "DIM" or "ON."
lP Filter
The Low Pass (LP) Filter selector switch determines the operating mode of the
Fathom's built-in low pass filter.
"Off" defeats the low pass filter, completely removing this circuit from the
signal path.
"12 dB" sets the roll off slope of the low pass filter to a 12 dB per octave slope
(Butterworth alignment).
"24 dB" sets the roll off slope of the low pass filter to a 24 dB per octave slope
(Linkwitz-Riley alignment).
The 24 dB setting more aggressively attenuates high frequencies above the LP
Frequency setting (see below). If you are using the Fathom's built-in low pass
filter, experiment with the LP Filter slope setting to achieve the best transition
to your satellite speakers. If you prefer to use the filters and bass management
features in your receiver or preamplifier, defeat the
on-board filter by selecting the "Off" position.
lP Freq
The Low Pass (LP) Frequency selector knob allows the user to choose the roll-
off frequency of the Fathom's internal low pass filter. The frequency is variable
between 30 Hz (full counter-clockwise) to 130 Hz (full clockwise). This knob
does not affect the input signal in any way if the LP Filter switch is set to "Off".
80 Hz is a commonly used filter frequency and usually serves as a good starting
point for adjustments.
Page 16
IMPORTANT
| Fathom f112 & f113