User manual QSC AUDIO UF-3 UNIVERSAL FILTER

[. . . ] Owner's Manual UF-3 Universal Filter *TD-004031-00* *TD-004031-00* Rev. DESCRIPTION The UF-3 is an embedded dual-channel universal filter accessory for use with select QSC power amplifiers. Compatible amplifier models and lines, both current and discontinued, include: · · · · · · · All PLX, two-channel CX, and two-channel DCA models (with a BSC-3 or BSC-5 BusCard installed) All four-channel CX and DCA models (with a BSC-7 BusCard installed) PowerLight models PL 1. 0, PL 1. 0HV, PL 1. 4, PL 1. 5X, PL 1. 6HVX, PL 1. 8, and PL 2. 0HV (with a BSC-2 or BSC-4 BusCard installed) PowerLight models PL 3. 4, PL 3. 8X, and PL 4. 0 (with a BSC-6 BusCard installed) All MXa models (MX 1000a, MX 1500a, MX 2000a, and MX 3000a; Note: does not include MX 700), which use Level 1 Open Input Architecture All EX models (EX 800, EX 1250, EX 2500, and EX 4000), which use Level 2 Open Input Architecture Legacy CX models CX6, CX6T, CX12, and CX12T, which use Level 1 Open Input Architecture Using the UF-3 as a default crossover or EQ is ideal for rental sound systems, since it virtually eliminates the possibility of unauthorized tampering with settings or other such user errors. Physically, the UF-3 is a small circuit card that mounts inside the amplifier. [. . . ] Insert a resistor network in RNx02 that is appropriate to the desired roll-off frequency-- typically 16 or 20 kHz. Ultrasonic roll-off Figure 6--UF-2 as an ultrasonic filter Typ. 16­20 kHz Bandpass Filter A bandpass filter may be useful if the speaker system driven by the amplifier has a limited bandwidth. Minimizing the out-of-the-passband energy may result in reduced distortion and better intelligibility. Set the jumper on Jx01 to enable the low-pass filter (across pins 2 and 3). Set the jumper on Jx02 to enable the high-pass filter (across pins 2 and 3). Insert a resistor network in RNx04 that corresponds to the lower limit of the desired frequency passband. Insert a resistor network in RNx02 that corresponds to the upper limit of the desired frequency passband. This frequency must be higher than the one selected for the previous step. CD Horn Equalization Filter A constant-directivity horn requires a 6 dB per octave high-frequency boost from about 3. 5 kHz to provide a flat frequency response. On the UF-3 you must use the CD horn equalization in conjunction with the high-pass filter. Set the jumper on Jx01 to bypass the low-pass filter (across pins 1 and 2). Set the jumper on Jx02 to enable the high-pass filter (across pins 2 and 3). Set the jumper on Jx03 to select the EQ curve you desire: across pins 1 and 2 for +6 dB at 20 kHz, or across pins 2 and 3 for +10 dB at 20 kHz. Insert a resistor network in RNx04 that corresponds to the desired low-frequency roll-off. Subsonic Filter with CD Horn EQ Use settings 1, 2, and 4 from the Subsonic Filter, and setting 3 from the CD Horn Equalization Filter. This would be suitable only if the loudspeaker system uses passive crossovers. CD Horn boost Subsonic roll-off Figure 7--UF-2 as a subsonic filter with CD horn EQ Subsonic and Ultrasonic Filter Use settings 2, 3, and 4 from the Subsonic Filter along with 2 and 3 from the Ultrasonic filter. Typ. 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. UF-3: Mids & Highs 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 highpass filter at 20 Hz (for subsonic filtering) and the low-pass at 150 Hz, which is the crossover point to the woofers. 1 PowerLight 1. 6 HVX 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. UF-3: Woofers Ch. 2 LP @ 1000 Hz; HP @ 150 Hz 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). For ultrasonic protection, the low-pass is set at 20 kHz. BSC-6 BusCard Ch. [. . . ] If you need to make any adjustments to the UF-3 settings or if you need to record them, do so now, because the UF-3 will be inaccessible once the input panel is re-installed into the amplifier chassis. Carefully reposition the input board/UF-3 assembly into the amplifier chassis and secure it by fastening the two mounting screws. Make sure the screws are tightened snugly, but do not over-torque them. Installation of the UF-3 is now complete, and the amplifier is ready to be reinstalled into the system. VI. [. . . ]