How to Choose a Subwoofer for Your Boat
By BOSS Audio Systems | Life at Full Volume | Published: 2026-10-20
Category: How-to Guides
Learn what to look for in a marine subwoofer, from size and mounting depth to power handling. Compare the BOSS CX122 and BAB8 to find your fit.
Quick Answer
For most boat owners, choose a subwoofer that fits your available mounting depth and matches your amplifier's power. The BOSS Audio CX122 delivers strong 12-inch bass if you have space; the BAB8 is a low-profile option for tight spots.
Why Boats Need a Different Subwoofer
Boats have unique challenges: limited space, exposure to moisture, and open-air listening. A subwoofer that works in a car trunk may not fit under a seat or in a console on a boat. You need to consider mounting depth and enclosure size before looking at power ratings.
Another factor is that boats often use higher-impedance speakers to work with marine head units. Check your amplifier's output at the impedance you plan to run. If you're unsure, a powered subwoofer with built-in amplification can simplify the install.
Power vs. Space: The Real Trade-Off
A larger subwoofer like a 12-inch model can move more air and produce deeper bass, but it needs a bigger enclosure and more mounting depth. A low-profile 8-inch subwoofer fits in shallow spaces but won't hit as low or as loud.
Think about where you'll mount it. If you have a dedicated enclosure under a helm seat, a 12-inch can work. If you're squeezing into a side panel or under a bench, a shallow-mount model is the practical choice.
Decision Rules for Choosing a Boat Subwoofer
- Measure Your Mounting Depth: Before anything else, measure the available depth where you plan to install the subwoofer. If you have at least 5.5 inches, a 12-inch like the CX122 can work. If less, go with a low-profile model like the BAB8. Write down the measurement and keep it with you when comparing specs.
- Match Power to Your Amplifier: Check your amplifier's RMS output at the subwoofer's impedance. A 1400-watt peak subwoofer needs an amp that can deliver enough clean power. If you don't have an amp, consider a powered subwoofer with a built-in amp. Aim for an amp that provides 75-100% of the subwoofer's RMS rating, not the peak rating.
- Choose Size Based on Listening Goals: If you want deep, room-filling bass and have space, pick a 12-inch subwoofer. If you need to save space and still want decent bass, an 8-inch low-profile model is the right call. Remember that a smaller subwoofer will not reproduce the lowest frequencies as loudly as a larger one.
Subwoofer Options at a Glance
- CX122: The BOSS Audio CX122 is a 12-inch subwoofer with a total power output rating of 1400 watts and a mounting depth of 5.4 inches. This gives you strong low-frequency output if you have enough depth for the enclosure, making it a good match for larger boat consoles or custom boxes.
CX122 - BAB8: The BOSS Audio BAB8 is a low-profile 8-inch subwoofer with 800 watts peak power and a rubber surround. Its shallow design fits tight spaces like under seats or in small compartments, while still delivering punchy bass for a compact setup.
BAB8
Who Should Choose Which
Best For
- Boat owners with a custom enclosure or large console who want maximum bass output
- Those upgrading from factory speakers and looking for a noticeable low-end boost
Not For
- Boats with very shallow mounting areas or limited enclosure space—consider a low-profile model instead
- Listeners who prefer a compact install and are okay with less deep bass extension
