Down4Sound SB8D4

2x2Ω
2x4Ω

Subwoofer

Nominal diameter8″ / 216 mm
Resonance39.6 Hz
Q factor0.54
Sensitivity81.3 dB
Linear excursion± 21 mm
Program Power1000 W
Driver
Port
Combined
Frequency response
Hz
Impedance
Ω
Impedance Phase
°
Excursion
mm
Velocity
m/s
SPL
dB
Acoustical Phase
°
Group Delay
ms
Transient response
ms
Discard
Apply

Specifications

  • Sensitivity (1W, 1m, infinite baffle) SPL1W 81.3dB

Thiele & Small parameters

  • Resonance frequency (free air) fS 39.6Hz
  • Mechanical quality factor QMS 3.12
  • Electrical quality factor QES 0.66
  • Total quality factor QTS 0.54

Large signal parameters

  • Maximum linear excursion (one way) xmax 21mm
  • Air volume displaced at xmax VD 441cm³
  • Power handling P 500W
  • Program power Pmax 1000W

Voice Coil

  • Nominal impedance Z 2 x 4Ω
  • DC resistance (in series) RE 5.8Ω
  • Inductance (1kHz, in series, estimated) LE 3.35mH
  • VC Diameter 63.5mm

Magnet

  • Force factor (in series) Bl 17.1N/A
  • Motor constant Bl/√RE 7.12N/√W
  • Height 60mm

Diaphragm

  • Effective diameter 164mm
  • Effective area SD 210cm²
  • Moving mass MMS 134g
  • Moving mass (without air load) MMD 131g

Suspensions

  • Stiffness KMS 8.28N/mm
  • Compliance CMS 121µm/N
  • Equivalent volume to the compliance VAS 9.33L
  • Mechanical resistance RMS 0.773N·s/m

Dimensions

  • Nominal diameter 8
  • 216mm
  • Overall diameter 216mm
  • Baffle cutout diameter 180mm
  • Mounting depth 127mm
  • Volume occupied by the driver 1.98L
  • Net weight 13.608kg

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