7
Ch. 2
Ch. 1
UF-3
PowerLight 1.6
HVX
Ch. 2
Ch. 1
UF-3
PowerLight 3.4
(parallel mode)
Ch. 2
Ch. 1
UF-3
PowerLight 4.0
(bridged mode)
Ch. 1:
Ch. 2
LP @ 150 Hz; HP @ 20 Hz
Bypassed
UF-3: Subwoofer
Ch. 1:
Ch. 2
LP @ 1000 Hz; HP @ 150 Hz
LP @ 1000 Hz; HP @ 150 Hz
UF-3: Woofers
Ch. 1:
Ch. 2
LP @ 5 kHz; HP @ 1000 Hz
LP @ 20 kHz; HP @ 5 kHz
UF-3: Mids & Highs
BSC-2
BusCard
BSC-6
BusCard
BSC-6
BusCard
Multi-way Crossover System
The UF-3 allows you to set up 3- and even 4-way systems. Of course, this also requires that you use more than one amplifier and more than one
UF-3. The other basic requirement of using the UF-3 as a crossover is that you must feed each amplifier with the same full-range signal and use
the UF-3 to filter the signals in the individual channels.
Figure 9 depicts an example of a 4-way system. Because of the multitude of possible system configurations, the fundamentals of the technique
used in the example will be explained below, with a few specifics.
The actual crossover frequencies you should use will depend on your
speaker system.
Subwoofer
The subwoofer subsystem in the example is driven by a bridged
amplifier. Channel 1 of the UF-3 in this amplifier is set with the high-
pass filter at 20 Hz (for subsonic filtering) and the low-pass at 150 Hz,
which is the crossover point to the woofers. Channel 2 of the UF-3 is
bypassed.
Woofer
The woofers are driven by an amplifier operating in the parallel
mode. Both channels of its UF-3 are set with the high-pass filter at
150 Hz (the crossover point from the subwoofers) and the low-pass
filter at 1 kHz.
Midrange and High Frequencies
The remaining speakers are driven by the same amplifier: the mids
by channel 1, and the highs by channel 2. The settings for channel 1
of the UF-3 are: high-pass at 1 kHz (the crossover from the woofers)
and low-pass at 5 kHz (the crossover point to the high-frequency
drivers).
Channel 2 of the UF-3 is set for high-pass at 5 kHz. For ultrasonic
protection, the low-pass is set at 20 kHz.
V. INSTALLATION
Installating the UF-3 requires PC board soldering skills, so only qualified service technicians should attempt it. Any authorized QSC service
center—or, for an additional installation fee, QSC Technical Services Group—can perform the installation.
The UF-3 installs on a BusCard, which mounts inside the amplifier. Make sure you have the right BusCard for the amplifier model.
The UF-3 also installs on the amplifier input PC board of any QSC EX, MXa, or legacy CX Series amplifier. Some older EX amplifiers may require
an upgrade to the current input board. Contact the QSC Technical Services Group for details on compatibility with older EX amplifiers.
When installed, the UF-3 settings and adjustments are not externally adjustable; this can prevent tampering by unauthorized users.
Figure 10—Multiple amplifiers with UF-3s, set up for 4-way crossover
operation
