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Cinema Loudspeaker Systems User Manual

SB-5218 and SB-7218 Dual-18” Subwoofers

Introduction

The SB-5218 and SB-7218 are specially designed cinema subwoofers, featuring dual 500 and 700 watt, respectively, 18” (460mm) low-frequency transducers mounted in ported enclosures. The enclosures are tuned to 25 hertz and use a B6 alignment. These should be used with the B6 boost filter option provided by the QSC SF-1 or SF-3 Subwoofer Filter mod- ules or the QSC Digital Cinema Monitor to ensure extended response to the lowest audible frequencies.

Meeting cinema requirements for the extended low frequency response differentiates the SB-5218 and SB-7218 from more conventional “rock-and-roll” subwoofer systems. Their fre- quency range extends to below 25 hertz when used with the correct B6 filter.

The two custom 500 watt (700 watt, SB-7218), 18” transducers were developed especially for cinema use. The woofers feature 4” (100mm) voice coils and vented pole pieces to ensure cool operation, even at high power levels. Cooler temperatures increase driver lifespan and decrease problematic power compression at high drive levels. Undercut pole pieces provides a Symmetrical Magnetic Gap (SMG), reducing second harmonic distortion.

Enclosures are constructed of high quality MDF panels and feature Single Woofer Chambers (SWC). The separate chamber for each transducer makes the enclosure stronger, provides rigidity, and prevents cone over-excursion in the rare event of a driver failure (enclosure “loading” is not lost for the remaining transducer).

Large, Fully Radiused Ports (FRP) ensure smooth air flow through the ports, especially at higher drive levels. This prevents potentially audible port turbulence noise. Both internal and external port openings are fully radiused.

With Symmetrical Port Loading (SPL) bass ports are evenly spaced on each side of the trans- ducers, making internal pressure more uniform across the back surface of the transducer. This prevents the cone from being displaced to one side or another by unbalanced air pres- sure, reducing the chance of driving the voice coil out of the center of the gap at high drive levels.

Enclosure is not designed to be suspended, flown, or rigged. Do not sus- pend, fly, or rig this enclosure.

This product is capable of producing sound pressure levels that can perma- nently damage human hearing. Always keep sound pressure levels in the listening area below levels that can damage human hearing.

Install in accordance with QSC Audio Product’s instructions and a licensed, professional engineer. Only use attachments, mounts, accesso- ries, or brackets specified by QSC Audio Products, Inc. Refer all servicing to qualified personnel. Servicing is required when the apparatus has been damaged in any way.

WARNING! Before placing, installing, rigging, or suspending any speaker product, inspect all hardware, suspension, cabinets, transducers, brackets and associated equipment for damage. Any missing, corroded, deformed or non-load rated component could significantly reduce the strength of the installation, placement, or array. Any such condition severely reduces the safety of the installation and should be immediately corrected. Use only hardware which is rated for the loading conditions of the installation and any possible short-term unexpected overloading. Never exceed the rating of the hardware or equipment. Consult a licensed, professional engineer when any doubt or questions arise regarding a physical equipment installa- tion.

EN

*TD-000150-00*

TD-000150-00 rev.B © Copyright 2003, 2004, QSC Audio Products, Inc.

QSC® is a registered trademark of QSC Audio Products, Inc. “QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office

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QSC Audio SB-5218, SB-7218 specifications Introduction, MacArthur Blvd., Costa Mesa, CA, 92626 USA