JBL 4348 - Manual (Page 3)

III. Bi-amp Configuration Using Two Power Amplifiers and Internal Networking
Remove the short wires with the gold plated ring sleeves, and connect the high-frequency and low-frequency
amplifiers to their respective terminals. Although the two power amplifiers do not need to be identical, they should
have similar output performance and same gain, or gains set to the same level in advance, through input adjustments
IV. Bi-amp Configuration Using Two Power Amplifiers and a Commercial Channel Divider
Using a Phillips screwdriver, remove the screws on the
subhatch located towards the top of the back panel. Remove
the hatch.
Switch the mode switch inside to "Biamp" using a flat-head
screwdriver, then screw the hatch back on.
Remove the short wires with the gold plated ring sleeves, and
connect the high-frequency and low-frequency amplifiers to
their respective terminals.
If you are using a channel divider that has a high-frequency
level controller, the gain on the two amplifiers do not need to
be the same.
*Caution
Except for bi-amp configuration with a channel divider, always keep the mode switch in the "Normal" position.
The positive terminals of the speaker have a red ring, and the negative terminals have a black ring. Be sure to connect
with out mistaking the polarity. The speakers are designed so that when a positive signal is applied to the positive
terminal, the woofer moves in the forward direction (positive phase operation).
When using the short wires with the gold plated ring sleeves, be sure that both the sleeves and the conductors are securely
fastened to the terminals. In addition, use extra caution so that the cable conductors do not touch other sleeves and short
out.
In order to safely and securely connect to the terminals, we recommend that you use the Y terminals or banana plugs on
the cable ends.
5. Attenuator Adjustment
Independent, continuous variable attenuators are used for each unit to adjust the MF (mid-frequencies), HF (high-
frequencies) and UHF (ultra-high-frequencies) levels to the speaker’s woofer level. The 0 dB position for each volume
knob indicates a flat-level position in a test room, where there is little reverb. Make adjustments appropriate to the reverb
in the actual room, and to your liking. In general, for most speakers, it takes about 1 – 2 months after initial use until the
unit's vibration system yields optimum performance. As the level balance is expected to initially change with use, we
recommend that you readjust the level accordingly.
The speakers are shipped with the grill installed.
The purpose of the grill is to protect the units. The grill may be removed
and re-attached as necessary.
The speaker has separate UPPER and LOWER grills. Furthermore, the
UPPER and LOWER parts each have a top side and a bottom side, so
attach them according to the figure to the right.
6: Attaching the Grills