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SF-1
Subwoofer
Filter
FPO
Rev. A
9
Owner’s Manual
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SF-1 SUBWOOFER FILTER INTRODUCTION The SF-1 Subwoofer Filter is an upper slot accessory for QSC MXa Series amplifiers, which feature Level One Open Input Architecture. The accessory mounts in the back of the amplifier above the standard input panel. Ideal for adding subwoofer amplification to an existing full-range system, the SF-1 offers adjustable and selectable low-pass filtering for both channels of the amplifier, in addition to adjustable high-pass subsonic filtering. The filter slopes are
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CONFIGURATION SETTING THE SUBSONIC FILTER FREQUENCY The subsonic (highpass) filter on Channel 1 cannot be bypassed, and Channel 2 should only be bypassed in the bridged mono mode. Plug-in SIP resistor network RN3 sets the high-pass frequency for both channels 1 and 2. Table 2 shows the resistor value to be used for the frequency you desire. Typical subsonic frequencies available with the provided SIP resistor networks are 20, 25, 32, 35, 40, 50, 63, and 80 Hz. Consult your subwoofer manufacturer
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Stereo, Bridged Mono, and Parallel Mono If the two subwoofer channels are to carry different or independent program material, as in stereo or bridged mono, set the SF-1 for “Stereo” operation. Use this also for parallel mono operation from a single program signal source. For stereo, bridged mono, or parallel mono operation, set the amplifier mode switch to “STEREO,” “BRIDGED,” or “PARALLEL,” respectively, and SW2 as follows: Position 1 ON Position 2 OFF Position 3 OFF Position 4 ON Position 9
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INSTALLATION Before installing the SF-1, disconnect the amplifier’s power cable from the AC mains. 1. Position the amplifier so that the rear panel is facing you. Locate the input panel and the blank accessory panel above it. 2. Remove the four mounting screws—the two holding the blank panel and the two holding the standard input panel. Remove the blank panel (which the SF-1 will replace) and carefully pull the input panel out from the amplifier chassis (figure 2a). 3. Disconnect the ribbon cabl
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SPECIFICATIONS SIGNAL TO NOISE RATIO (22 Hz to 22 kHz): 103 dB TOTAL HARMONIC DISTORTION <0.1 % CROSSTALK 70 dB below rated power within passband CMRR: better than 50 dB FILTER TYPE second-order butterworth, Q=0.707 (LPF and unboosted subsonic filter) second-order, +6 dB boost, Q=2 (boosted subsonic filter) DIP SWITCH FUNCTIONS TABLE 3—DIP SWITCH SW2 Mode 1 2 3 4 5 6 7 8 9 10 Mono Sum OFF ON ON OFF Stereo ON OFF OFF ON Bypass Channel 2 (bridged mono) ON OFF Engage Channel 2 OFF ON Bypass Channe
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APPLICATION NOTES For cinema surround channels and subwoofers that do not require an EQ boost, use the following switch settings. SW1 slide switch- BOOST OFF SW2 DIP switch Position 1 ON Position 2 OFF Position 3 OFF Position 4 ON Position 5 ON Position 6 OFF Position 7 ON Position 8 OFF Position 9 ON if bridged mono, OFF otherwise Position 10 OFF if bridged mono, ON otherwise The high pass filter frequency for non-boosted subwoofers, such as the JBL 4645 and Electro-Voice systems NOT being us
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APPENDIX A: WARRANTY & DISCLAIMERS DISCLAIMER QSC Audio Products, Inc. is not liable for any damage to speakers, amplifiers, or any other equipment that is caused by negligence or improper installation and/or use of the SF-1 Subwoofer Filter. PRODUCT WARRANTY QSC Audio Products, Inc. guarantees the SF-1 Subwoofer Filter to be free from defective material and/or workmanship for a period of three years from date of sale, and will replace defective parts and repair malfunctioning products under thi
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QSC TECHNICAL SERVICES DEPARTMENT 1675 MacArthur Blvd Costa Mesa, CA 92626 Telephone: (800) 772-2834 (714) 957-7150 (714) 754-6175 Fax: (714) 754-6173 Bulletin Board: (714) 668-7567 (800) 856-6003 INTERNATIONAL SERVICING For QSC products that are purchased outside of the United States, service must be referred to the distributor or dealer from where the product was purchased. There are numerous service centers in many countries. The service centers in your country may be located by your dealer
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QSC AUDIO PRODUCTS, INC. 1675 MacArthur Blvd., Costa Mesa, CA 92626 USA Ph (714) 754-6175 Fax (714) 754-6174 Email INFO@qscaudio.com Web http://www.qscaudio.com “QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office. 12
