Ground Zero Iridium GZIW 300 12" 350W RMS 4-Ohm High-Efficiency Car Subwoofer (400W Max)

The Ground Zero Audio Iridium GZIW 300 (MPN: GZIW 300 / GZIW300) is a high-sensitivity 12-inch (30 cm / 300 mm) daily car subwoofer engineered in Germany with a 3D-structured HQPP cone and Klippel®-optimized motor. Rated at 350 Watts RMS (200W–400W recommended amplifier power) with a Single 4-Ohm voice coil, high 88 dB efficiency, and 28 mm (1.10″) Xmax, the Iridium GZIW 300 produces deep, punchy 30 Hz bass in sealed or vented trunk enclosures without requiring heavy electrical upgrades.

Key Features & Acoustic Engineering

• High 88 dB Sensitivity & 350W RMS Power Handling: Driven by a 50 mm (2″) copper voice coil that delivers loud, dynamic 12-inch sub-bass from just 200W to 400W RMS of amplifier power.
• 3D HQPP Cone & 28 mm (1.10″) Xmax: Rigid 3D-structured HQPP polypropylene cone paired with a long-stroke rubber surround, Polycot spider, and resonance-free steel basket.
• Klippel® Laser-Optimized Motor & 30 Hz Fs: Tuned on Ground Zero’s Klippel® distortion analyzer for linear cone motion and smooth low-frequency extension.
• Single 4-Ohm Impedance: Wire a single GZIW 300 to a 4-Ohm mono or bridged multi-channel amplifier, or wire a pair of GZIW 300 12″ subwoofers in parallel to a 2-Ohm monoblock load.

Recommended Amplifier & Enclosure Pairing

• Amplifier Match (200W–400W RMS @ 4-Ohm): Pair with a compact micro mono amplifier (such as the Ground Zero GZRA 450.1-MICRO or GZRA 700.1-MICRO) from our Ground Zero Amplifiers collection.
• Enclosure Fitment Specs: Performs in sealed, vented/ported, and bandpass 12-inch enclosures (11.30″ / 287 mm cutout diameter; 5.87″ / 149 mm mounting depth; 2.45 cu. ft. / 69.3 L Vas).
• 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). Custom subwoofer boxes and professional installation available across Toledo, Maumee, Perrysburg, Sylvania, Holland, Bowling Green, and Southeast Michigan. Call (419) 376-6140 for support.