The Aftershock 18 powered subwoofer delivers professional low-end reinforcement for DJs, bands, churches, and mobile performers who need deep bass extension without breaking the budget. This 18-inch powered sub handles the foundation frequencies that smaller speakers simply cannot reproduce.

Built around an 18-inch woofer with a 90 oz magnet and 3-inch voice coil, the Aftershock 18 produces 800 watts RMS of clean bass power. The built-in amplifier eliminates the need for external power amps, while the low-pass filter lets you dial in the crossover point from 40Hz to 200Hz to match your main speakers perfectly.

The onboard mixer provides four line inputs and outputs via 1/4" and XLR combo jacks, plus two powered satellite outputs delivering up to 200 watts per channel at 4 ohms. This means you can run your main speakers directly from the subwoofer, creating a complete powered PA system from a single unit. The 3-band EQ and individual clip lights help you optimize the sound for any venue.

Perfect for wedding receptions, church worship services, club gigs, and outdoor events handling crowds up to 200-300 people. The 98dB sensitivity ensures efficient power transfer, while the 5/8" plywood construction and black carpet finish provide durability for regular transport.

Connect your mixer or audio source using standard XLR or 1/4" cables. The speaker pole mount on top accommodates most PA speakers for compact system setup.

Backed by Seismic Audio's one-year warranty with fast shipping nationwide.

Technical Specifications

Frequently Asked Questions

What size venue can the Aftershock 18 handle?

The Aftershock 18 works well for venues accommodating 200-300 people, including wedding receptions, church sanctuaries, club gigs, and outdoor events. The 800-watt RMS power and 98dB sensitivity provide enough bass reinforcement for medium-sized spaces without overwhelming smaller rooms.

Can I connect my main speakers directly to this subwoofer?

Yes, the Aftershock 18 includes two powered satellite outputs that deliver up to 200 watts per channel at 4 ohms. You can run your main PA speakers directly from the subwoofer using the Speakon outputs, creating a complete powered system. This eliminates the need for separate power amplifiers.

What cables do I need to connect this subwoofer?

You'll need standard XLR or 1/4" cables to connect your mixer or audio source to the subwoofer's combo input jacks. If using the powered satellite outputs, you'll need Speakon cables to connect your main speakers. All input and output connections use common professional audio cable types.

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

Use the built-in low-pass filter control to adjust the crossover point from 40Hz to 200Hz. Start around 80-100Hz for most full-range speakers, then adjust by ear. The goal is seamless blending where the subwoofer handles the low end without overlapping too much with your main speakers' bass response.

Do I need two subwoofers or will one Aftershock 18 be enough?

For most DJ gigs, small to medium churches, and indoor events up to 250 people, one Aftershock 18 provides sufficient bass reinforcement. Larger venues, outdoor events, or bass-heavy music genres may benefit from two units. The daisy chain capability makes it easy to add a second subwoofer later if needed.

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