Cinema Accessories for DCA Series amplifiers USER MANUAL XC-3 LF-3 SF-3 Two-way crossover with delay Low-frequency filter with delay Subwoofer filter *TD-000079-00* TD-000079-00 rev. B 1 IMPORTANT SAFETY INFORMATION: PLEASE REVIEW! EXPLANATION OF GRAPHICAL SYMBOLS The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to humans. The exclamation point within an equilateral triangle is intended to alert the users to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION: To reduce the risk of electric shock, do not remove the cover. No user-serviceable parts inside. Refer servicing to qualified service personnel. WARNING: To prevent fire or electric shock, do not expose this equipment to rain or moisture. SAFEGUARDS Electrical energy can perform many useful functions. This unit has been engineered and manufactured to assure your personal safety. Improper use can result in potential electrical shock or fire hazards. In order to not defeat the safeguards, observe the following instructions for its installation, use and servicing. · Maximum operating ambient temperature is 50° C. · When installing equipment into a rack, distribute the units evenly. Uneven weight distribution can be hazardous. · Connect the unit only to a QSC DCA, CX, or PL2 Series amplifier. · Maintain reliable earthing (grounding) of all rackmounted equipment. WARNING! While QSC has endeavored to develope and produce the most dependable and robust Cinema Accessory for your use, QSC cannot be held responsible for damages resulting from any deviation or failure by the user to strictly follow the recommendations set forth in the user manual. All risks attendant to integration of user-configurable Cinema Accessories with your sound system are assumed by you. While QSC strives to supply the highest quality technical solutions, in no event will QSC or its suppliers be held liable for any damages, consequential, incidental, or otherwise, including any claims for lost profits and/or savings resulting from any attempted integration of the cinema accessories which does not strictly adhere to the manual's recommendations. ©Copyright 1998, 2002 QSC Audio Products, Inc. All rights reserved. "QSC," "DCA," "DataPort," and the QSC logo are registered trademarks of QSC Audio Products, Inc. 2 TABLE OF CONTENTS INTRODUCTION Introduction and description of each model.................................4 CONFIGURING THE ACCESSORIES General configuration information, all models...............................5 XC-3 Setting up the XC-3....................................................................6 Factory-installed SIPs..........................................................6 Factory-switch settings.........................................................7 Recommended amplifier settings......................................7 Illustrations: Setup flow chart, XC-3 front and rear, delay and crossover SIP selection charts, SIP identifier chart, and HF boost response curve. LF-3 Setting up the LF-3....................................................................8 Factory-installed SIPs..........................................................9 Factory switch settings.........................................................9 Recommended amplifier settings......................................9 Illustrations: Setup flow chart, LF-3 front and rear, delay and crossover SIP selection charts, SIP identifier chart. SF-3 Setting up the SF-3....................................................................10 Factory-installed SIPs.........................................................11 Factory switch settings.........................................................11 Recommended amplifier settings......................................11 Illustrations: Setup flow chart, SF-3 front and rear, low-pass/high-pass SIP selection chart, SIP identifier chart. MOUNTING TO AMPLIFIER...............................................12 APPLICATION EXAMPLE......................................................................13 WARRANTY INFORMATION.........................................14 HOW TO CONTACT QSC AUDIO PRODUCTS ....................15 3 INTRODUCTION & DESCRIPTION OF EACH MODEL Introduction This manual covers setup and operation of cinema crossover accessories for QSC DCA Digital Cinema Amplifiers. There are 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 by plugging into the amplifier's DataPort and is secured with three screws. Operating power and all connections between the accessory and amplifier are provided by the DataPort connection. Frequency and delay parameters are user-adjustable by inserting selected 8-pin SIP resistor networks into sockets on the underside of the accessory. A DIP switch permits selection of functions such as delay and high-frequency boost, depending upon model. Each accessory includes an assortment of the proper SIP resistor networks and three mounting screws. Keep the unused SIPs for future use. Description of each model 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. An all-pass filter on the low frequency band delays the audio signal, permitting time alignment of a cone driver with a high-frequency horn. A selectable high-frequency boost circuit provides several increments of compensation for screen loss or constant-directivity horn equalization. A HF trim control provides 0 to 20 dB of attenuation for matching levels between frequency bands. The XC-3 can be used by itself with one amplifier for a 2-way system (shown opposite page, bottom-left), or with the LF-3 and an additional amplifier for 3-way systems, as shown, opposite page, bottom-right. The XC-3 has a pass-through output in parallel with the input for distributing the audio signal to the LF-3. The filter circuitry uses a 4th-order Linkwitz-Riley alignment with 24 dB/octave slopes. LF-3 Used in a system with the XC-3, the LF-3 performs the low-frequency crossover functions in a 3-way system as shown, opposite page, bottom-right. Unlike the XC-3, it has two discrete channels; one LF-3 with an amplifier will support two other amplifiers with two XC-3 accessories, as shown. The 4th-order Linkwitz-Riley low-pass filters have 24 dB/octave slopes. Each channel has an all-pass filter providing delay for time alignment. Frequency and delay parameters for both channels are set individually, although typically they would be set the same. Each channel has a trim control that provides 0 to 20 dB of attenuation for matching levels among the various frequency bands. SF-3 The SF-3 Subwoofer Filter has two summed inputs and a bandpass filter that defines the frequency range of the subwoofer program. The frequencies of the 2nd-order high-pass and 4th-order Linkwitz-Riley low-pass filters are both set by the user by selecting and installing the appropriate SIP networks. The high-pass filter also has a switchable low-frequency boost feature: switched on, it provides a 6 dB bump at the selected high-pass frequency, useful for extending the low-end response of some speaker systems; off, the response is a flat Butterworth curve that is 3 dB down at the selected frequency. The output is parallel, feeding the same signal into both channels of the amplifier. The SF-3 has no delay function. A level trim control provides 0 to 20 dB of attenuation. The SF-3 can be used to derive subwoofer-range program from full-range audio, as shown, opposite page, bottom-left. It can also be used with a discrete subwoofer channel in cinema sound systems. 4 CONFIGURING THE ACCESSORIES Configuring the Accessories Configure each accessory before you mount it to the amplifier. If an accessory is already mounted to an amplifier, always turn the amplifier off before changing switch settings, changing input or output connections, or detaching the accessory. Use the tables on the following pages to determine the correct SIP resistor network value for the desired frequency and delay settings. SIP identification charts are included to help you identify the values of the resistor networks. A flowchart for each model will help you properly configure the accessory. Configurable functions of the three accessory models 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 socket 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. 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. Using the XC-3 and LF-3 in a stereo three-way system Using the SF-3 with a discrete subwoofer channel 5 XC-3 Setting up the XC-3 Setting up the XC-3 Setup flowchart for the XC-3 Setting up the XC-3 requires setting the DIP switches and selecting/inserting SIP resistors into the appropriate sockets. DIP switches #2, #9, and #10 must be set to the ON position (default settings for the XC-3). The flowchart below takes you through all the steps necessary before mounting the accessory to the amp. The illustration below shows the locations of the sockets for the SIP resistor networks. The SIP resistor networks can be inserted either way, as long as each network pin goes into its own hole in the socket. Straighten the pins, if needed, before inserting the SIP into its receptacle. Use the tables on the following 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 f XO of 80 Hz to 1.5 kHz, and delay settings from 0.3 to 1.8 milliseconds; contact QSC's Technical Services Group if your application requires different settings. 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. XC-3 Factory-installed SIPs fXO LF delay fHP 500 Hz (12 k SIP resistor in J1) 1.8 milliseconds (27 k SIP resistor in J2) 80 Hz (68 k SIP resistor in J7) XC-3 controls, switches, and SIP socket locations 6 XC-3 XC-3 Factory Switch Settings Setting up the XC-3 When shipped from the factory, the DIP switch settings should be set as follows: Switches 7 & 8 ON: Switch 1 ON: Switches 3 through 6 OFF: Switches 2, 9, and 10 ON: sets XC-3 to Biamp mode activates LF delay HF boost disabled Factory default settings for proper operation. XC-3 Recommended Amplifier Settings Clip limiters: ON (both channels) Low frequency filters: ON (both channels), select either 30 or 50 Hz roll-off, depending on speaker specifications (both channels) Operating mode: stereo Use these tables to determine the correct resistor values for the crossover frequencies and delays you need. The shaded values are for the high-pass frequency (fHP) of the XC-3. 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 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 Identifying SIP resistor networks 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). 7 LF-3 Setting up the LF-3 Setting Up the LF-3 Setup flowchart for the LF-3 Setting up the LF-3 requires setting the DIP switches and selecting/inserting SIP resistors into the appropriate sockets. DIP switches #2 and #4 through #9 must be set to OFF, and switch #3 set to ON (factory default for proper operation). The flowchart , right, takes you through the steps necessary before mounting the accessory to the amp. The LF-3 is typically used in a system in co ...