Fi Car Audio HT-1 18 S4

• Sensitivity (1W, 1m, infinite baffle) SPL1W 87.8dB

Thiele & Small parameters

• Resonance frequency (free air) fS 20.9Hz
• Mechanical quality factor QMS 5.75
• Electrical quality factor QES 0.57
• Total quality factor QTS 0.51

Large signal parameters

• Maximum linear excursion xmax 27mm
• Air volume displaced at xmax VD 3267cm³
• Power handling P 1000W
• Program power Pmax 2000W

Voice Coil

• Nominal impedance Z 4Ω
• DC resistance RE 2.9Ω
• Inductance (1kHz, estimated) LE 4.05mH

Magnet

• Force factor Bl 18.8N/A
• Motor constant Bl/√RE 11.1N/√W

Diaphragm

• Effective diameter 393mm
• Effective area SD 1210cm²
• Moving mass MMS 518g
• Moving mass (without air load) MMD 488g

Suspensions

• Stiffness KMS 9.23N/mm
• Compliance CMS 108µm/N
• Equivalent volume to the compliance VAS 222L
• Mechanical resistance RMS 11.8N·s/m

Dimensions

• Nominal diameter 18″
• 470mm
• Overall diameter 470mm
• Baffle cutout diameter 425mm
• Mounting depth 165mm
• Volume occupied by the driver 5.1L