Powering Up - JBL SP-150 Instruction Manual

POWERING UP

A) ON/AUTO/OFF
You may choose to have your Subwoofer turn on automatically once it senses an incoming signal. In that case
please select the "Auto" position on the back of the amplifier. The amplifier will turn itself off to stand-by mode if it
does not sense a signal after approximately 10 seconds. When listening at very low levels, the amplifier's signal
may be too low to turn the amplifier on automatically. In such cases please select the "On" position on the amplifier.
B) PHASE
The Phase switch allows your subwoofer to match the output of the bass driver in relation to the other speakers in
the listening room. The correct position for this switch is whichever way produces more perceived bass. You may
experiment by switching between 0º and 180º, and determining which position sounds best. In most cases, howev-
er, leaving the switch in the 0º position will produce the best results.
C) SETTING THE VOLUME AND CROSSOVER FREQUENCY
The Crossover Frequency control determines the frequency below which the subwoofer will play. This frequency is
manually controlled and is continuously variable between 50-150Hz.You can experiment with which position works
best with your main speakers by turning this control until the sound of the low frequency coming from the sub-
woofer is nicely blended with the sound of your main speakers.
Crossover setting tip:
When using small speakers (speakers with a 50" or less main woofer) set this control toward the "50" position. When using
larger speakers (speakers with an 8" or more main woofer) set the control closer to the "50" position.
D) VOLUME
When setting the volume control at the subwoofer, begin with your main speakers playing at a normal listening
level and the volume control at the subwoofer completely in the off position (counterclockwise position). Then,
begin to turn up the volume at the subwoofer slowly (clockwise) until the desired bass response is achieved. Bass
output will then be regulated by your A/V receiver's volume control.
Volume setting tip:
Have one person sit at the regular listening position, and a second person turn up the volume at the subwoofer until the
desired bass output is achieved at the listening position. Remember most natural sounding bass results when bass repro-
duction is balanced with the main speakers.