The UK's leading Integrator and Equipment
Installer for the Digital Cinema Industry


SB-5218 / SB-7218 logo

Founded over four decades ago, QSC Audio Products, LLC, is a globally recognized leader in the design and manufacture of professional audio system solutions. Sound Associates have been specifying and installing QSC amplifiers for use in cinemas large and small for many years and now with Q-Sys we continue to deliver high quality cinema sound.

QSC introduced a full range of cinema speakers and Sound Associates is proud to have carried out all of the UK installations of their stage, sub-bass and surround speakers. The range now includes digital signal processing (DSP) and, again, Sound Associates have carried out numerous installations, both here in the UK as well as overseas.

In 2016 QCS acquired Ultra-Stereo Labs, Inc. (USL) allowing them to offer an industry-leading porfolio of sound processing solutions for the motion picture exhibition industry.

SB-5218 / SB-7218

Part of the DCS Digital Cinema Speaker Series, QSC's SB-5218 and SB-7218 subwoofers offer a unique solution that addresses the requirements of digital motion picture soundtracks. Featuring dual 18"" low frequency transducers mounted in ported enclosures, these systems extend response to the lowest audible frequency.

The two custom 18"" transducers were developed especially for cinema use. The woofers feature 4"" voice coils and vented pole pieces to ensure cool operation, even at high power levels. Cooler temperatures increase driver lifespan and decrease power compression at high drive levels. Undercut pole pieces provide a symmetrical magnetic gap, reducing second harmonic distortion.

Enclosures are constructed of high-quality MDF panels and feature single woofer chambers. The separate chamber for each transducer makes the enclosure stronger, provides rigidity, and prevents cone overexcursion in the rare event of a driver failure. Enclosure ""loading"" is not lost for the remaining transducer.

Large, fully radiused ports ensure smooth airflow, especially at higher drive levels. This prevents potentially audible port turbulence noise. Both internal and external port openings are flared.

With symmetrical port loading, the bass ports are evenly spaced on each side of the transducers, making internal pressure more uniform across the back surface of the woofer. This prevents the cone from being displaced to one side or another by unbalanced air pressure, reducing the chance of driving the voice coil out of the center of the gap at high drive levels.


  • SB-5218 features dual 500 watt transducers.
  • SB-7218 features dual 700 watt transducers.
  • Frequency range extends to below 25 Hz when used with the correct B6 filter.
  • DCM and SF-3 signal processors optionally available.
  • Enclosures feature vandal-resistant woofer mounting bolts.
  • THX Approved.

Download Datasheet

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