JBL owner manual Controls and Functions, Tuning the MPS1000

CONTROLS AND FUNCTIONS

The MPS1000 has several controls and indicators that simplify sonic integration with the rest of the speakers on your boat. To gain access to the controls, you must remove the cover and the water-tight rubber plug underneath. To remove the cover, remove the two small Phillips-head screws and pull the cover away, according to the arrow in Figure 4. To reinstall the cover, follow the arrows in Figure 6 and replace the two screws.

Figure 4. Removing cover

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Figure 7. MPS1000 controls on the front panel

0° Phase180°			MPS1000
min		max 50	80		max
	Gain		120 min	Boost
		Crossover

TUNING THE MPS1000

1.	Make sure the head unit is off and its volume control is set to
	minimum.
2.	On the MPS1000’s front panel, set the Gain control to the midpoint
	position.
3.	Set the Crossover control to its maximum position (clockwise).
4.	Set the Bass Boost control to the minimum position
	(counterclockwise).
5.	Set Phase to 0.°
6.	Turn on the head unit and play a favorite music track that has
	substantial bass. Set the head unit’s volume control to 75% of the
	total output (approximately 3 o’clock on rotary controls).
7.	Listen to your system, making a mental note of the amount of upper
	bass being reproduced.
8.	Switch the Phase control to 180° and listen again for upper bass
	content. There may be more upper bass, less upper bass, or no
	change at all. The position that provides the most upper bass is
	correct.
9.	Adjust the Crossover control clockwise or counterclockwise
	until you hear only low-frequency information in the output of the

Figure 5. Rubber plug

0° Phase180°			MPS1000
min		max 50	80		max
	Gain		120 min	Boost
		Crossover

NOTE: Be sure to replace the rubber plug after making adjustments.

Figure 6. Reinstalling cover

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Power LED: This indicator will glow blue when the MPS1000 is operational.

Gain Control: Use this control to adjust the volume (loudness) of the MPS1000, compared to the loudness of the other speakers in your boat.

Crossover: Use this control to adjust the amount of high-frequency information in the MPS1000’s output. A lower value means less high-frequency signal will be present in the MPS1000’s output.

Bass Boost: Use this control to correct any perceived peak or dip in the bass response. This control provides boost or cut at 50Hz. Set the control to any value between 0dB and +7dB, according to your preference.

Phase Control: Use this switch to reverse the phase of the MPS1000’s output, with respect to its input. Choose the position (0° or 180°) that sounds best. See “Tuning the MPS1000”.

MPS1000. For example, you should NOT hear any vocals coming

from the MPS1000 when seated in the normal listening position.

10. Adjust the Bass Boost control clockwise to suit your preference.

NOTE: In most cases, the steps above will provide satisfactory tuning. However, the actual process may require several readjustments of each control, since the settings will interact with each other. If necessary, consult your authorized JBL car or marine audio dealer for help in tuning your system.

NOTE: Depending on the MPS1000’s orientation and location in your boat, reversing the phase may (or may not) increase or decrease the amount of upper bass being reproduced.

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