The Quad-18 delivers massive low-end output for large venues, outdoor festivals, and sound reinforcement systems that demand serious bass extension. This passive subwoofer cabinet houses four 18-inch drivers in an innovative cone-to-cone configuration that maximizes power handling while minimizing cabinet size.

The coupled driver design effectively doubles power handling to 2,400 watts peak per pair (4,800 watts total), while reducing distortion compared to traditional single-driver enclosures. Each pair of drivers acts as a single unit, creating exceptional low frequency response down to 30Hz with 104dB sensitivity.

Built from solid birch plywood with a protective metal grille, the cabinet features dual impedance loads of 4 ohms each, requiring separate amplifier channels or a bridged stereo amp. Each side provides both 1/4-inch and Speakon connectors for flexible connection options. At 234 pounds, this is a substantial piece of gear designed for permanent installations or large mobile rigs.

The Quad-18 handles venues up to 1,000+ people and pairs well with full-range PA speakers for concerts, DJ performances, churches with contemporary worship services, and outdoor events requiring deep bass coverage. The 47.25-inch width makes it suitable for stage-front deployment or ground-stack configurations.

Standard speaker cables connect from your amplifier to the cabinet's input connectors. Due to size and weight, freight shipping is required rather than standard ground delivery. Backed by Seismic Audio's one-year warranty, the Quad-18 brings professional-grade bass reinforcement to serious sound systems.

Technical Specifications

Frequently Asked Questions

What size venues can the Quad-18 handle?

The Quad-18 is designed for large venues with 500-1,000+ people, including concert halls, outdoor festivals, large churches, and major events. With 4,800 watts total peak power handling and 104dB sensitivity, it provides the deep bass extension needed for substantial crowd coverage. For smaller venues under 300 people, a single 18-inch or dual 15-inch subwoofer would be more appropriate.

What amplifier power do I need to drive the Quad-18?

You'll need a stereo amplifier capable of delivering at least 1,200 watts RMS per channel into 4 ohms, or a single bridged amp providing 2,400+ watts into the combined load. Each side of the cabinet presents a 4-ohm impedance and can handle 1,200 watts RMS. Popular choices include QSC, Crown, or Seismic Audio power amplifiers in the 2,000+ watt range.

What cables do I need to connect the Quad-18?

Standard speaker cables with either 1/4-inch or Speakon connectors work with the Quad-18. Speakon connections are recommended for high-power applications due to their locking design and better power handling. You'll need two separate cable runs from your amplifier since each side of the cabinet requires its own connection. Use 12-gauge or thicker speaker wire for runs over 25 feet.

How does the cone-to-cone driver configuration work?

The cone-to-cone design pairs two 18-inch drivers facing each other within the same cabinet section, effectively coupling their output. This configuration doubles the power handling capacity while reducing the air volume needed compared to separate driver chambers. The result is higher output, lower distortion, and more efficient use of cabinet space than traditional designs.

Do I need a crossover or DSP with the Quad-18?

Yes, you'll need an active crossover or DSP to properly integrate the Quad-18 with your full-range speakers. Set the low-pass filter around 80-120Hz depending on your main speakers' capabilities. The subwoofer's 30Hz-200Hz response is designed to be crossed over electronically rather than running full-range, ensuring clean integration with your PA system's mid and high frequencies.

WARNING: This product can expose you to chemicals including Di(2-ethylhexyl)phthalate (DEHP), which is known to the State of California to cause cancer. For more information, go to: www.P65Warnings.ca.gov