The Aftershock-18 powered subwoofer pair delivers professional bass reinforcement for DJs, bands, churches, and mobile performers who need to fill medium to large venues with deep, controlled low end. Each 18-inch subwoofer produces 800 watts RMS of clean power, ensuring your audience feels every kick drum and bass line.

These powered subs handle the heavy lifting in your PA system, extending frequency response down to where passive speakers struggle. The built-in amplification eliminates the need for external power amps, while the integrated crossover and satellite outputs let you connect your main speakers directly to the subwoofer for a streamlined setup.

Each cabinet features a robust 18-inch woofer with 90 oz magnet and 3-inch voice coil, delivering 98 dB sensitivity at 8 ohms impedance. The onboard processing includes a variable low-pass filter (40Hz-200Hz), 3-band EQ, and dedicated satellite amplifier sections providing 2x120 watts at 8 ohms or 2x200 watts at 4 ohms. Multiple XLR and 1/4" inputs plus Speakon outputs accommodate any mixer or speaker configuration.

Perfect for wedding receptions up to 400 guests, church sanctuaries, club gigs, and outdoor festivals where you need serious bass extension without the complexity of separate amplifiers. The rugged 5/8" plywood construction with carpet finish and metal corners handles the rigors of regular transport.

Connect your mixer to the combo XLR/1/4" inputs, then run your main speakers from the built-in satellite amplifier outputs. Each 89-pound cabinet includes recessed handles and top-mounted pole socket for main speaker mounting. One-year warranty and direct shipping from Seismic Audio ensure reliable performance and support.

Technical Specifications

Frequently Asked Questions

What size venues can the Aftershock-18 pair handle?

This subwoofer pair works well for venues accommodating 200-400 people, including wedding receptions, church sanctuaries, school gymnasiums, and medium-sized clubs. The 800 watts RMS per cabinet provides enough bass reinforcement for contemporary worship music, DJ sets, and live bands without overwhelming smaller spaces or underperforming in larger ones.

What cables do I need to connect these subwoofers to my mixer and main speakers?

You'll need XLR or 1/4" cables to connect from your mixer to the subwoofer inputs, then Speakon cables to run from the subwoofer satellite outputs to your main speakers. This eliminates the need for separate power amplifiers since the subwoofers have built-in amplification for both the subs and your main speakers.

Can I use just one Aftershock-18 instead of buying the pair?

While you can purchase single units separately, most live sound applications benefit from stereo bass reinforcement, especially for DJ gigs and contemporary church music. A single subwoofer works for smaller venues under 150 people, but the pair provides better bass distribution and handles larger crowds more effectively.

How do I set the crossover frequency for my main speakers?

Use the variable low-pass filter control to set where the subwoofer stops and your main speakers take over, typically between 80-120Hz depending on your main speakers' low-frequency response. Start at 100Hz and adjust by ear - lower settings give you deeper bass, higher settings provide more punch and blend better with smaller main speakers.

Do these subwoofers work with any brand of main speakers?

Yes, the Aftershock-18 satellites outputs are compatible with any passive PA speakers. The Speakon outputs deliver 2x120 watts at 8 ohms or 2x200 watts at 4 ohms, which matches most 12-15 inch PA speakers. Check your main speakers' power handling and impedance to ensure proper matching.

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