Fi Car Audio BTL4 18 D1

2x1Ω
2x2Ω

Subwoofer

Nominal diameter18″ / 470 mm
Resonance24.8 Hz
Q factor0.53
Sensitivity88.3 dB
Linear excursion± 33 mm
Program Power7000 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
  • Sensitivity (1W, 1m, infinite baffle) SPL1W 88.3dB

Thiele & Small parameters

  • Resonance frequency (free air) fS 24.8Hz
  • Mechanical quality factor QMS 7.61
  • Electrical quality factor QES 0.56
  • Total quality factor QTS 0.53

Large signal parameters

  • Maximum linear excursion xmax 33mm
  • Air volume displaced at xmax VD 3993cm³
  • Power handling P 3500W
  • Program power Pmax 7000W

Voice Coil

  • Nominal impedance Z 2 x 1Ω
  • DC resistance (in series) RE 1.4Ω
  • Inductance (1kHz, in series, estimated) LE 2.11mH

Magnet

  • Force factor (in series) Bl 14.3N/A
  • Motor constant Bl/√RE 12.1N/√W

Diaphragm

  • Effective diameter 393mm
  • Effective area SD 1210cm²
  • Moving mass MMS 567g
  • Moving mass (without air load) MMD 537g

Suspensions

  • Stiffness KMS 13.7N/mm
  • Compliance CMS 73µm/N
  • Equivalent volume to the compliance VAS 151L
  • Mechanical resistance RMS 11.6N·s/m

Dimensions

  • Nominal diameter 18
  • 470mm
  • Overall diameter 470mm
  • Baffle cutout diameter 425mm
  • Mounting depth 241mm
  • Volume occupied by the driver 2.83L


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