JL Audio f212 owner manual Master Level Knob, Lights, LP Filter, LP Freq

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.

IMPORTANT

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