SBR-S8D4.2 Alpine R-Series 8" Ported Enclosed Subwoofer

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  • Regular price $399.95
Tax included.



  • 900W Peak Power
  • 300W RMS Power
  • High Amplitude Multi Roll (HAMR) surround
  • Frequency Response: 28Hz – 400Hz
  • USA Designed Slot Ported Subwoofer Enclosure
  • Heavy Gauge Spring Terminals
  • Dimensions: (L x W x H cm) 49 x 29 x 16
  • R2-W8D4 Pre-installed
  • Grille Included and Pre-Installed


  • Subwoofer Size: 8″
  • Power Handling (RMS/Peak): 350W/1000W
  • Power Range (RMS): 150W-350W
  • Frequency Response (Hz): 28Hz-200Hz
  • Diaphragm Material: Kevlar-Reinforced Pulp Fiber
  • Diaphragm Design: 2-piece structural parabolic
  • Surround Material: Injection molded santoprene
  • Surround Design: High Amplitude Multi-Roll (Patent Pending)
  • Spider Material: Nomex
  • Spider Design: Progressive
  • Voice Coil Material: 180˚C High Temp Wire on Spiral Cut Aluminium Former
  • Voice Coil Design: 4-Layer Dual Voice Coil
  • Motor Structure Pole Geometry: Compound Radius Curve
  • Motor Structure Configuration: Integration Shorting Sleeve with Radial Vented VC Head Transfer
  • Magnet Material: High-Power Strontium Ferrite
  • Magnet Configuration: 6-Piece (8″) / 10-Piece (10″/12″) Radially Segmented, Double Stacked
  • Frame Material: Cast Aluminium
  • Frame Design: Single-Piece Casting with Airflow Management System
  • Terminals Layout: One sided
  • Terminals Design: Heavy Duty 8ga, Push with housing, Banana Sockets for VC Configuration Jumpers
  • Tinsel Leads Design: Reinforced Layer Spider Integration
  • Gasket Design: Concealed Mount Gasket System and Integrated Grill Ready



  • Nominal Impedance: 2ohms+2ohms
  • Frequency Response: 28-200Hz
  • Sensitivity (SPL @ 1W/1m): 83.5dB
  • D.C Coil Resistance (Re): 1.85ohms +1.85ohms
  • Inductance (Le) 1kHz/20kHz: 0.87mH/0.30mH
  • Free Air Resonance (Fs): 38Hz
  • Equivalent Stiffness (Vas): 12L (0.42 ft³)
  • Mechanical Q (Qms): 7.8
  • Electrical Q (Qes): 0.55
  • Total Q (Qts): 0.50
  • Xmax10 (One-Way Xmax @ 10% Distortion): 14mm
  • Mechanical Excursion, Peak-to-Peak: 52mm
  • Gap Height (Hag): 10mm
  • Coil Height (Hvc): 29mm
  • Cone Area (Sd): 201 cm²
  • Voice Coil Diameter: 40mm (1.6″)
  • Magnet Weight: 52oz


The SBR-S8D4 features Alpine’s Type-R 8″ subwoofer in a custom slot ported enclosure. Ideal for installation in small spaces, its compact size means it can fit virtually anywhere.

The pre-installed subwoofer employs many features typically found in larger models, such as Alpine’s H.A.M.R (High Amplitude Multi Roll) suspension. This unique design allows greater linear excursion while improving control, to achieve maximum output and outstanding sound quality.

Designed to achieve optimal output, the carpeted enclosure features heavy duty MDF construction. Plus, stylish brushed aluminium laminate and a robust grill create the perfect balance of stunning aesthetics and practicality.


Owner's Manual