Operation
Power
When the unit is plugged in and power is on and no signal is received, the LED on the front of the unit will turn red. When a signal is present, the LED will turn green. Note:
It will take several minutes for the LED to turn from green to red after the input signal to the subwoofer is removed. Due to JBL’s unique, high- efficiency digital-amplifier design, power consumption is minimal when the subwoofer is not receiving a signal. Of course, the subwoofer can be turned off, whenever desired.
Level Control
The subwoofer Level Control, located on the front panel, adjusts the volume of the subwoofer relative to the rest of the system. Proper level adjustment depends on several variables such as room size, subwoofer placement, type of
main speakers and listener position. Adjust the subwoofer level so that the volume
of the bass information is pleasing to you.
Video Contour
The video-contour switch, located on the front panel, optimizes the subwoofer’s performance for movie listen- ing. When the video-contour switch is on, the subwoofer’s performance is tailored to deliver the impact and
excitement of today’s movies. The green LED will illuminate when the video-contour switch is on.
Crossover Adjustments
Low-Pass Control
The low-pass control deter- mines the highest frequency at which the subwoofer reproduces sounds. If your main speakers can comfortably reproduce some low-frequency sounds, set this control to a lower frequency setting, between 50Hz – 100Hz. This will concentrate the subwoofer’s efforts on the ultradeep bass sounds required by today’s films and music. If you are using smaller bookshelf speakers that do not extend to the lower bass frequencies, set the low-pass crossover control to a higher setting, between 120Hz – 180Hz.
High-Pass Control
•If you hooked up your sub- woofer as shown in Hookup 4 on page 5, you also have the capability of adjusting the high-pass frequency. The high-pass control determines the frequency at which the main speakers will start reproducing sounds. If your main speak- ers can comfortably repro- duce some low-frequency sounds, also set this control to a lower frequency setting, between 50Hz – 100Hz. This will concentrate the subwoofer’s efforts to the ultradeep bass sounds, while your main speakers continue to reproduce the mid-bass information. If you
are using smaller bookshelf speakers that do not extend to the lower bass frequencies, set the high-pass crossover control to a higher setting, between 125Hz – 180Hz. With this setting, your main speakers will not have the burden of reproducing any low-frequency sounds.
•If you hooked up your sub- woofer as shown in Hookup 1 on page 3, the high-pass frequency is fixed at 180Hz.
•If you hooked up your subwoofer as shown in Hookup 2 or Hookup 3 on page 4, no high-pass- control adjustments can be made from the subwoofer. Unless your receiver/
amplifier incorporates a high-pass crossover, your main speakers will continue to get a full-range signal.
Final adjustment and blending of the low-pass and high-pass controls may evolve over sev- eral listening sessions. A good starting point would be to set both the low- and high-pass controls to the same frequency and adjust from that point.
