Alpine R2-W10D4 10" R-Series "R2" Subwoofer, Dual 4-Ohm, 750 Watt RMS PRODUCT OVERVIEW The next generation of sound performance is here with the new R-Series subwoofers featuring a larger motor structure for more accurate and authoritative bass. New Motor Structure – The new R-Series subwoofers now feature larger, double-stacked magnets that contribute more motor force for deeper bass and tighter bass control compared to the previous generation. Oversized Dust Cap – The new hybrid poly ceramic composite dust cap ensures rigidity while also providing incredible internal damping (vibration absorption) to smooth out the bass response and reproduce tight bass. Increased Accuracy – Alpine's High Amplitude Multi-Roll (HAMR) Surround Technology allows the cone to efficiently move air while staying cool resulting in incredible accuracy from the subwoofer. General Specs: Size: 10” Dimensions: 9.72” x 9.72” x 5.92” Frequency Response: 26Hz - 200Hz Power Range: 300W - 750W RMS Power Handling: 750W RMS / 2250W Peak Magnet Weight: 123 oz Voice Coil Diameter: 65.5 mm (2.6”) T/S Parameters: Sensitivity (1W/1m): 82.8 dB DC Resistance (Re): 3.5Δ + 3.5Δ Free Air Resonance (Fs): 32 Hz Equivalent Stiffness: 18.2 L Mechanical Q (Qms): 6.50 Electrical Q (Qes): 0.52 Total Q (Qts): 0.48 Cone Area (Sd): 333 cm2 Linear Excursion (Xmax): 20 mm Mechanical Travel (Xmech): 70 mm BOX SPECS - SEALED BOX RANGE: Net Internal Volume: 0.4 - 0.85 ft3 RECOMMENDED SEALED BOX: External Dimensions: 12” x 12” x 10.5” Gross Internal Volume: 0.58 ft3 Net Internal Volume: 0.50 ft3 VENTED BOX RANGE: Net Internal Volume: 0.75 - 1.3 ft3 Fb, Tuning: 35-39 Hz RECOMMENDED VENTED BOX: External Dimensions: 13” x 11.5” x 25.25” Gross Internal Volume: 1.58 ft3 Vent Area (W x H): 15 in2 (10” x 1.5”) Vent Length: 19.5” Vent Displacement: 0.25 ft3 Net Internal Volume (Vb): 1.25 ft3