Ground Zero Hydrogen GZHW 8SPL-D2 Flat 8" 500W RMS Dual 2-Ohm Shallow Subwoofer (800W SPL)

The Ground Zero Audio Hydrogen GZHW 8SPL-D2 Flat (MPN: GZHW 8SPL-D2 FLAT / GZHW8SPL-D2-FLAT) is an ultra-shallow 8-inch (20 cm / 200 mm) high-output SPL subwoofer engineered in Germany for Harley-Davidson bagger saddlebags, under-seat pickup truck enclosures, and UTV audio builds. Featuring a compact 3.15″ (80 mm) mounting depth, 500 Watts RMS / 800 Watts SPL power handling, Dual 2-Ohm (2x 2-Ohm) voice coils, and 24 mm (0.94″) Xmax, the GZHW 8SPL-D2 Flat delivers authoritative mid-bass and sub-bass impact in micro enclosures with just 0.50 cu. ft. (14.2 L) Vas.

Vehicle, Truck & Harley Bagger Fitment Highlights

• Ultra-Shallow 3.15″ (80 mm) Mounting Depth: Fits effortlessly inside Harley-Davidson Street Glide and Road Glide saddlebags, under-seat and behind-seat truck boxes (Ford F-150/Super Duty, Chevy Silverado/GMC Sierra, Ram, Tacoma), spare-tire wells, and side-by-side UTV sub enclosures.
• 500W RMS / 800W SPL Power Handling: Driven by a 4-layer copper voice coil and solid die-cast aluminum basket built to handle 350W to 800W of continuous power.
• 24 mm (0.94″) Long-Stroke Excursion: Reinforced sandwich paper cone and durable high-roll U-shape rubber surround with a Klippel®-optimized motor reaching down to a 31.5 Hz resonance frequency (Fs).
• Dual 2-Ohm (D2) Wiring Flexibility: Wire a single GZHW 8SPL-D2 Flat in parallel to a 1-Ohm load (or 4-Ohm series), or run a pair of 8″ flat subwoofers at a 2-Ohm final impedance.

Recommended Amplifier & Enclosure Pairing

• Amplifier Match (350W–800W RMS): Pair with a high-efficiency compact amplifier from our Ground Zero Amplifiers or SounDigital lineup for custom car, truck, or Motorcycle Audio installations.
• Enclosure Fitment Specs: Optimized for ultra-compact sealed and vented enclosures (7.36″ / 187 mm cutout diameter; 3.15″ / 80 mm mounting depth).
• Explore More Ground Zero Subwoofers: Browse all Ground Zero Subwoofers in our catalog.

Technical Specifications & Thiele-Small Parameters

Authorized US Ground Zero Audio Dealer & Custom Installation in Toledo, OH: Ships fast from TDS Car Audio (6540 Central Ave, Suite O, Toledo, OH 43617). We build custom Harley bagger saddlebag systems and under-seat truck enclosures for customers in Toledo, Maumee, Perrysburg, Sylvania, Holland, Bowling Green, and Southeast Michigan. Call (419) 376-6140 for fitment support.