Alpine SBR-S8D4.2 900W 8” Compact Subwoofer (with included grille | SWR-823D Pre-installed)

by Alpine

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.


  • 900W Peak Power
  • 350W RMS Power
  • High Amplitude Multi-Roll (HAMR) surround
  • Frequency Response: 24Hz – 200KHz
  • USA Designed Slot Ported Subwoofer Enclosure
  • Heavy Gauge Spring Terminals
  • Dimensions: (L x W x H cm) 49 x 29 x 16
  • SWR-8D4 Pre-installed
  • Grille Included


  • 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 moulded 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 Heat 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