User manual QSC AUDIO DCA ACCESORIES

[. . . ] A DIP switch permits selection of functions such as delay and high-frequency boost. Using the XC-3 in a simple two-way system. In many speaker systems, a passive mid/high combination will handle the higher frequencies, creating essentially a three-way system. Ch. 1 MF XC-3 full-range audio audio plein registre Vollbereichaudio audio de gama llena 2-way crossover HF Ch. Description of Functions XC-3 This accessory is a two-way crossover, with the low frequency band fed to channel 1 of the amplifier and the high frequencies to channel 2. [. . . ] A delay compensation of 1 millisecond represents approximately 1. 13 ft (13. 5 in), or 34. 4 cm. fXO LF delay 3-way 2-way +10 dB +7. 5 dB +5 dB +2. 5 dB fHP fXO XC-3 LF-3 NOTE: Even if you don't use a particular filter or delay feature on an accessory, put an unused SIP resistor network of any value into its socket to ensure circuit stability when it is powered up. The SIP resistor networks have no polarity and therefore do not need to be inserted in a certain direction. Make sure all eight pins are inserted properly into the sockets holes, and then gently but firmly press the network into the socket until it is fully seated. If a SIP resistor network is difficult to remove with your fingers, use a small screwdriver, prying gently first at one end of the SIP and then the other, until it is loose. LF flat Low pass filter on Low pass filter off LF boost Delay fHP fLP SF-3 Configurable functions of the three accessory models 4 Crossover freq. (fXO) 80 Hz 150 Hz 200 Hz 250 Hz 300 Hz 350 Hz 400 Hz 500 Hz 600 Hz 650 Hz 800 Hz 1 kHz 1. 2 kHz 1. 5 kHz SIP resistor value 68K 39K 27K 22K 20K 18K 15K 12K 10K 8. 2K 6. 8K 5. 6K 4. 7K 3. 9K Delay (ms) 1. 8 1. 4 1. 3 1. 2 1 0. 8 0. 7 0. 6 0. 5 0. 4 0. 3 SIP resistor value 27K 22K 20K 18K 15K 12K 10K 8. 2K 6. 8K 5. 6K 4. 7K Use only these three digits to determine resistance code. Disregard the other numerals and letters. Use these tables with the XC-3 and LF3 to determine the correct resistor values for the crossover frequencies and delays you need. The shaded values are for the LF-3 and the highpass frequency (fHP) of the XC-3). RESISTANCE 2. 7K 3. 9K 4. 7K 5. 6K 6. 8K 8. 2K 10K 12K 15K 18K 20K 22K 27K 33K 39K 47K 56K 68K CODE 272 392 472 562 682 822 103 123 153 183 203 223 273 333 393 473 563 683 Identifying SIP resistor networks Setting up the XC-3 This procedure involves setting the DIP switches, as well as selecting and inserting SIP resistors into the appropriate sockets. The flowchart on the next page takes you through all the steps necessary before mounting the accessory to the amp. The illustration on the next page shows the locations of the sockets for the SIP resistor networks. The resistor networks have no polarity or directionality and therefore do not need to be inserted in any particular way, as long as each network pin goes into its own hole in the socket. XC-3 controls and switches 1 OFF ON 1 1 2 3 4 5 6 7 8 9 10 Use the tables at the top of this page to select the correct resistor networks for the settings you need. The SIPs supplied with the XC-3 provide a selectable frequency range for fXO of 80 Hz to 1. 5 kHz, and delay settings from 0. 3 to 1. 8 milliseconds, plus bypass (no delay); contact QSC's Technical Services department if your application requires different settings. 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 HF boost = OFF HF boost = 2. 5 dB HF boost = 5 dB HF boost = 7. 5 dB HF boost = 10 dB 500 700 1k 2k 3k 4k 5k 6k 7k 8k 9k10k 15k 20k 30k 40k 50k Effects of high frequency boost on frequency response (crossover frequency = 500 Hz). A boost of +10 dB is most common for compensating for screen loss (attenuation of high frequencies as sound passes through screen perforations) and for constant-directivity horns. 5 J1 (fXO) 3-way Switches 7 & 8 = OFF 2- or 3-way?2-way Switches 7 & 8 = ON Select fXO and fHP ; install appropriate SIPs in J1 (f XO ) and J7 (fHP ) Select fXO ; install appropriate SIP in J1 Install SIP (any value) in J7* No Switch 1 = OFF Need LF delay? Yes Switch 1 = ON J2 (LF delay) J7 (fHP) Install SIP (any value) in J2* Select delay; install appropriate SIP in J2 Locations of SIP sockets on the XC-3 When using the XC-3 in a three-way system in conjunction with the LF-3, the lower frequency (fHP) should match the crossover frequency of the LF-3 (fXO). The SIPs supplied with the XC-3 allow a selectable frequency range for fHP of 80 to 500 Hz. No Need HF boost? Yes 10 dB (CD horn) Switch 6 = ON; Switches 3­5 = OFF 7. 5 dB Switches 3­6 = OFF Switch 3 = ON; Switches 4­6 = OFF 2. 5 dB 5 dB FACTORY SIP SETTINGS fXO LF delay f HP 500 Hz (12K SIP resistor in J1) 1. 8 ms (27K SIP resistor in J2) 80 Hz (68K SIP resistor in J7) Switch 4 = ON; Switches 3, 5, 6 = OFF Switch 5 = ON; Switches 3, 4, 6 = OFF *To ensure circuit stability Attach to amplifier Setup flowchart for the XC-3 FACTORY SWITCH SETTINGS Bi-amp mode (switches 7 & 8 = ON) LF delay active (switch 1 = ON) HF boost defeated (switches 3 through 6 = OFF) Switches 2, 9, & 10 = ON RECOMMENDED AMPLIFIER SETTINGS WITH THE XC-3 Clip limiters ON, both channels Stereo mode High-pass filter ON, both channels High-pass frequency 30 or 50 Hz, both channels 6 Setting up the LF-3 J8 (Ch. 1 delay) This procedure involves setting the DIP switches, as well as selecting and inserting SIP resistors into the appropriate sockets. The flowchart below takes you through all the steps necessary before mounting the accessory to the amp. The LF-3 is typically used in a system in conjunction with the XC-3 crossover. For example, a stereo three-way system will require three DCA amplifiers, two XC-3 cinema crossover accessories, and one LF-3 lowfrequency cinema accessory, as shown on page 2. The typical input signal is full-range audio taken from the male XLR connector labeled "OUTPUT (TO LF-3)" on the XC-3. The illustration to the left shows the locations of the 1 2 3 4 5 6 7 8 9 10 OFF ON J6 (Ch. 2 delay) Locations of SIP sockets on the LF-3 sockets for the SIP resistor networks. The resistor networks have no polarity or directionality and therefore do not need to be inserted in any particular way, as long as each network pin goes into its own hole in the socket. LF-3 controls and switches Select fXO for Ch. 1 and Ch. 2) Use the tables at the top of page 5 to select the correct resistor networks for the crossover frequency (fXO) and delay settings you need. [. . . ] Watch the frequency response on the analyzer and use the HF trim control on the XC-3 and the LF trim on the LF-3 to balance the levels of their frequency bands to that of the the mid-frequency band, within specifications. If the shape of the HF response is not correct, use a boost setting that better corrects the deficiency; turn the amplifiers off before changing the switch settings. Repeat this process for the center and right screen channels and any surround channels that are bi- or tri-amped. Follow the processor instructions for setting sound pressure level outputs of all the channels, including the subwoofer. [. . . ]