Sky High Car Audio FMX Series 6.5" Subwoofer

Sky High Car Audio FMX Series Subwoofers

Available in 6.5” – 18” (excludes 10”)

D1/D2 Ohm Options

FMX: Forged to Perform. Built to Endure.

The FMX Series from Sky High Car Audio is the result of years of innovation, real-world testing, and deep involvement in the high-output car audio scene. Every aspect of this line reflects our passion for pushing limits—from competition lanes to daily builds. Drawing from decades of experience and leadership in the industry, the FMX lineup represents a smarter, stronger class of subwoofers purpose-built for those who demand reliable performance and lasting thermal stability.

For installs with limited space that still demand serious output, the FMX 6.5” and 8” subwoofers deliver unmatched punch and clarity with class-leading motor force and thermal control in their size class. Built around triple-stacked Y35 ferrite motors and finished with standard forged carbon fiber cones and dust caps, these woofers pack heavyweight power into compact footprints.

The FMX Series 6.5” features a 600W RMS rating, driven by a 2” high-temp coil, and stabilized by a 5.5” progressive spider. It’s equipped with Sky High 10-gauge direct leads, ensuring clean power transfer and reliable long-term use. Despite its small size, the 6.5” FMX hits with control and depth, making it ideal for tight spaces or multi-driver setups where output and efficiency matter.

The FMX Series 8” steps things up with a 2.5” voice coil, 800W RMS power handling, and a precision-tuned 6.5” progressive spider. A rated 16mm Xmax allows serious stroke, while 10-gauge direct leads ensure efficient electrical flow under demanding use. With a larger motor and extended coil, the 8” FMX delivers both high end bass articulation and deep low-end authority in small enclosures.

As with the rest of the FMX family, both models come finished in a stealth black aesthetic, including the forged carbon fiber dust cap recessed into the cone for strength, and a full fiberglass cone support underneath for added rigidity. These subs aren’t just made to look good—they’re built to last and perform.

Like their larger siblings, the 6.5” and 8” FMX offer excellent bandwidth and musical versatility—not just SPL peaks.

Box Designs: Sky High Car Audio is proud to partner with Hunter Martin from EZ DB’s, one of the most respected and proven enclosure designers in the industry. We’ll be offering FREE box designs—including ported, 4th order, and 6th order options where applicable—tailored specifically for our subwoofers to ensure maximum performance and reliability. As a bonus, any customer who purchases 4 or more BMX, FMX, or FXXL series subwoofers directly from Sky High Car Audio will receive a $50 credit toward a custom enclosure design from EZ DB’s, giving you a serious head start on a professionally designed, competition-ready subwoofer enclosure. Every SHCA subwoofer is tested using DATS-LA, measured with the backplate off the surface after full break-in, ensuring accurate and trustworthy TS data. 

SHCA-FMX-6 Enclosure Designs

Note: No customization options are available on the FMX 6.5” and 8” models. These subs come optimized and ready to perform straight out of the box. 

Welcome to the next tier of performance.

Welcome to the Sky High Car Audio Revolution.