JBL service manual Troubleshooting, E250P/P12SW subwoofers, Phase Control

E250P/P12SW subwoofers

Phase Control

The Phase Control determines whether the subwoofer’s pis- ton-like action moves in and out in phase with the main speakers or opposite the main speakers. There is no correct or incorrect setting. Proper phase adjustment depends on several variables such as subwoofer placement and listener position. Adjust the phase switch to maximize

bass output at the listening position.

Remember, every system, room and listener is different. There are no right or wrong settings; this switch offers the added flexibility to adjust your subwoofer for optimum per- formance for your specific listening conditions without having to move your speakers.

If at some time in the future you happen to rearrange your listening room and move your speakers, you should experi- ment with the phase switch in both positions, and leave it in the position that maximizes bass performance.

TROUBLESHOOTING

If you used the high-level (speaker) inputs and there is no sound from any of the speakers:

•Check that the receiver/ amplifier is on and a source is playing.

•Check that the powered subwoofer is plugged into an active electrical outlet and is switched on.

•Check all wires and connec- tions between the receiver/ amplifier and the speakers. Make sure all wires are con- nected. Make sure none of the speaker wires are frayed, cut or punctured, or touching each other, except for the wires for the front left and right speakers, which may be joined with the wires for the subwoofer at the receiver/ amplifier end only, if you are using the speaker-level connections as described on page 4.

•Review proper operation

of your receiver/amplifier.

If there is low (or no) bass output:

•Make sure the connections to the left and right “Speaker Inputs” have the correct polarity (+ and –).

•Make sure that the sub- woofer is plugged into an active electrical outlet and switched on.

•Adjust the crossover point.

•Flip the Phase Control switch to the opposite position.

•If you are using a Dolby Digital/DTS receiver or processor, make sure that the subwoofer adjustments on the receiver/processor are set up correctly.

•Slowly turn the Level Control clockwise until you begin to hear the desired amount of bass.

If you used the line-level inputs and there is no sound from the subwoofer:

•Check that the receiver/ amplifier is on and a source is playing.

•Check that the powered subwoofer is plugged into an active electrical outlet and is switched on.

•Check all wires and connections between the receiver/amplifier and the subwoofer. Make sure all wires are connected. Make sure none of the wires are frayed, cut or punctured, or touching each other.

•Review proper operation of your receiver/amplifier.

•Slowly turn the Level Control clockwise until you begin to hear the desired amount of bass.

•Make sure that you have configured your receiver/ processor so that the sub- woofer/LFE output is on.

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