JBL 4338 - 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.
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 HF (high-frequencies) and the 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.
7: Maintenance
• When doing any maintenance, wipe the surface of the cabinet with a dry cloth to remove dust. Damp cloth or cleaning
paper may dull the finish on the cabinet surface. Do not use volatile liquids such as benzene, paint thinner, alcohol, etc,
and do not spray insecticide near it.
• If dust gets into the grill netting, use a vacuum cleaner to remove it. In doing so, adjust the suction power of the
vacuum cleaner so that it does not suction too strongly. Furthermore, do not wash the grill in water. The grill may sag
or its color may become uneven.
• If the surface of the speaker unit becomes dusty, use a soft, dry calligraphy brush or a paint brush to carefully sweep the
dust away. Never use a damp cloth.
•The speaker system is a durable consumer good. In particular, the edges of the woofer, which support rapid movement
of the paper cone, undergo a great level of stress, and there is a limit to the number of years of its practical use. Also,
the speakers' lifespan may be shortened by the effects of temperature, humidity or ultra-violet radiation. Please avoid
exposing the speaker to strong lighting such as from lighting equipment or direct sunlight and avoid placing the
speakers in high temperatures such as near the air conditioner exhaust pipe or a heat radiator.
6: Attaching the Grills