Alpine's RS-W10D4 10-inch R-Series Shallow Subwoofer with Dual 4-Ohm Voice Coils. With an ultra-shallow subwoofer design and powerful sound output, the R-Series Shallow Subwoofers give you the best of both worlds in size and sound. A lightweight yet rigid aluminum dust cap allows the R-Series Shallow Subwoofer to transition sound quickly with minimal distortion and project the bass off the surface of the speaker for hard-hitting yet smooth bass performance. Alpine’s Gen2 DD-Linear Magnetic Circuit technology, a compact and efficient dual-gap voice coil structure, allows for better control over the motor, resulting in lower distortion and precise bass control. Don’t let the size fool you – the R-Series Shallow Subwoofers feature the same motor movement (20MM of excursion) as the full-size R2-Series Subwoofers for extreme output in a shallow woofer design. At the heart of the R-Series Shallow Subwoofers is an oversized 4-inch voice coil that houses the lightweight and powerful neodymium magnet for 600W RMS of power handling. ULTRA-SHALLOW DESIGN For those looking to add powerful, hard-hitting bass performance to their vehicle but lack the space to add a subwoofer, Alpine’s R-Series Shallow Subwoofer delivers the same fun and loud sound you’ve come to expect, now in a shallow subwoofer that’s designed to fit in most vehicle applications. EXTREME OUTPUT Don’t let the size fool you – the R-Series Shallow Subwoofers feature the same motor movement (20MM of excursion) as the full-size R2-Series Subwoofers for extreme output in a shallow woofer design. At the heart of the R-Series Shallow Subwoofers is an oversized 4-inch voice coil that houses the lightweight and powerful neodymium magnet for 600W RMS of power handling. Precise Bass Control Alpine’s Gen2 DD-Linear Magnetic Circuit technology, a compact and efficient dual-gap voice coil structure, allows for better control over the motor, resulting in lower distortion and precise bass control. FEATURES 10” High-Performance Shallow Bass Driver Alpine Gen2 DD Linear Magnetic Circuit Cast Aluminum Frame Aluminum Dust Cap Neodymium Magnet What's in the Box: 10” R-Series Shallow Subwoofer Owner’s Manual Warranty Information Online product registration information TECH SPECS Mounting Depth: 3.25” (82.55mm) X-Max: 20mm Voice Coil: 4”(102mm) Frequency response: 29Hz – 200Hz Sensitivity (1W/1M): 83bB Nominal Impedance: 4Ω 600W RMS / 1800W Peak Power Handling Compatible with KTE-RS10G Subwoofer Grille Kit (sold separately) RS-W10D4 - THIELE-SMALL PARAMETERS Sensitivity (1W/1m): 78 dB DC Resistance (Re): 3.6∆ + 3.6∆ Free Air Resonance (Fs): 31 Hz Equivalent Stiffness: 23.35 L Mechanical Q (Qms): 5.72 Electrical Q (Qes): 1.66 Total Q (Qts): 1.19 Cone Area (Sd): 380 cm2 Linear Excursion (Xmax): 20 mm Mechanical Travel (Xmech): 54 mm