Cinema Accessories for DCA Series amplifiers OFF ON USER MANUAL 1 2 3 4 PU SH 5 6 7 8 9 10 ▼ XC-3 Two-way crossover with delay ▼ LF-3 Low-frequency filter with delay ▼ SF-3 Subwoofer filter *TD-000079-00* TD-000079-00 Rev.
© Copyright 1998 QSC Audio Products, Inc. All rights reserved. “QSC” and the QSC logo are registered trademarks, and “DCA” and “DataPort” are trademarks, of QSC Audio Products, Inc.
CINEMA ACCESSORIES FOR DCA AMPLIFIERS I. Introduction This manual covers setup and operation of cinema crossover accessories for QSC DCA Digital Cinema Amplifiers. These accessories comprise three models: the XC-3 crossover, the LF-3 low frequency filter, and the SF-3 subwoofer filter. Together with DCA amplifiers, they allow you to assemble any type of cinema sound system, mono or multi-channel. Each accessory mounts directly to the back of the amplifier, from which Ch.
Each channel also has an all-pass filter providing delay for time alignment. Frequency and delay parameters for both channels are set individually, although in all but a few applications they would be set the same. Each channel also has a trim control providing 0 to 20 dB of attenuation to facilitate matching levels among the various frequency bands. SF-3 This subwoofer filter accessory has two summed inputs and a bandpass filter that defines the frequency range of the subwoofer program.
Crossover freq. (fXO) SIP resistor value Delay (ms) SIP resistor value 80 Hz 68K 1.8 27K 150 Hz 39K 1.4 22K 200 Hz 27K 1.3 20K 250 Hz 22K 1.2 18K 300 Hz 20K 1 15K 350 Hz 18K 0.8 12K 400 Hz 15K 0.7 10K 500 Hz 12K 0.6 8.2K 600 Hz 10K 0.5 6.8K 650 Hz 8.2K 0.4 5.6K 800 Hz 6.8K 0.3 4.7K 1 kHz 5.6K 1.2 kHz 4.7K 1.5 kHz 3.9K RESISTANCE 2.7K 3.9K 4.7K 5.6K 6.8K 8.
J1 (fXO) 3-way 2- or 3-way? 2-way Switches 7 & 8 = OFF Switches 7 & 8 = ON Select fXO ; install appropriate SIP in J1 Select fXO and fHP ; install appropriate SIPs in J1 (f XO ) and J7 (fHP ) Install SIP (any value) in J7* Need LF delay? No Yes Switch 1 = OFF Switch 1 = ON J2 (LF delay) Install SIP (any value) in J2* J7 (fHP) Select delay; install appropriate SIP in J2 Locations of SIP sockets on the XC-3 Need HF boost? When using the XC-3 in a three-way system in conjunction with the LF-3,
Setting up the LF-3 J8 (Ch. 1 fXO) J1 (Ch. 1 delay) This procedure involves setting the DIP switches, as well as selecting and inserting SIP resistors into the appropriate sockets. Set switches 2 and 4 through 9 to OFF, and switch 3 to ON. 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.
Setting up the SF-3 This procedure involves setting the DIP switches, as well as selecting and inserting SIP resistors into the appropriate sockets. First, set switches 1 through 6 and 10 to OFF. The flowchart on the opposite page takes you through all the steps necessary before mounting the accessory to the amp. OFF ON 1 2 3 4 5 6 7 8 9 10 The bottom right illustration details the locations of the two SIP sockets used on the SF-3.
high- lowpass pass Derived by filter highpass Is subwoofer program derived or discrete? Turn low-pass filter on Switches 7 & 8 = OFF Turn low-pass filter off Switches 7 & 8 = ON Select high-pass freq. (fHP); install appropriate SIP in J2. Select low-pass freq. (fL P); install appropriate SIP in J6. Select high-pass freq. (fHP); install appropriate SIP in J2.
V. Setting up the DCA accessories in the cinema sound system Setting up the DCA accessories in the B chain of the cinema sound system primarily involves setting the trim levels on the XC-3, LF-3, and SF-3. This requires the pink noise source in the cinema processor and a real-time acoustical spectrum analyzer. 1. Set up the analyzer microphone in the center of the cinema audience seating area or in another recommended location. 2.
APPENDIX Crossover and delay settings for popular cinema loudspeaker systems Consult your speaker documentation. Some data has not yet been determined. Also, the high-frequency horn of some of the systems listed have multiple mounting positions, so the desired delay settings will depend on the positioning chosen. Check the QSC website (http://www.qscaudio.com) for information updates. Brand JBL Model Crossover frequency (Hz) Delay (ms) 4675C 500 1.8 4670D 800 0.7 3678 1K 0 TS9040D-LX 500 1.
© Copyright 1998 QSC Audio Products, Inc. All rights reserved. “QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office. QSC Audio Products, Inc.
