Q-SYS SB-7218 Dual 18-Inch 700-Watt Cinema Subwoofer

Part of the DCS Digital Cinema Speaker Series, QSC’s 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 heavily braced, high-quality MDF panels and feature individual woofer chambers. 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 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.

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

Specifications:

• Frequency Range:
  • -6 dB, Half space: 22–100 Hz
  • -10 dB, Half space: 19–250 Hz
• Maximum Output:
  • Calculated Peak at rated power: 137 dB
  • Calculated Continuous: 130 dB
• Impedance: 4 ohms nominal
• Maximum Input Power:
  • 100 hours of 6 dB crest factor, IEC 268 noise spectrum
  • 2 hours of 6 dB crest factor pink noise, 50 Hz–20 kHz, AES method
• Recommended Amplifier Power:
  • 1200 watts continuous
  • 1500 watts continuous
  • 2600 watts continuous maximum
• Sensitivity:
  • 2 V at 1 meter, half space: 101 dB
• Transducers:
  • Two 18-inch (457 mm) 700-watt high-efficiency subwoofer transducers
  • Featuring 4-inch (100 mm) copper voice coils on Kapton formers
• Recommended Processing:
  • LF boost Freq.: 25 Hz
  • Q: 2.0
  • Gain: +6 dB
  • Provided by QSC, SF-3 or DCM
• Connectors: Barrier strip screw terminals accept up to #10 AWG stranded wire
• Enclosure:
  • B6 alignment, vented enclosure with symmetrical port design
  • Tuned to 25 Hz, constructed of MDF and heavily braced
  • Features vandal-resistant woofer mounting bolts
• Dimensions:
  • Inches (HWD): 48 × 30 × 24
  • Millimeters (HWD): 762 x 1220 x 610
• Weight: 210 lb (95 kg)