Celestion FTR18-4080FD

• Sensitivity (1W, 1m, infinite baffle) SPL1W 94.4dB
• Frequency response 30 - 2500Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 25.2Hz
• Mechanical quality factor QMS 4.75
• Electrical quality factor QES 0.30
• Total quality factor QTS 0.29

Large signal parameters

• Maximum linear excursion xmax 8.5mm
• Air volume displaced at xmax VD 964cm³
• Power handling P 1000W
• Program power Pmax 2000W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.6Ω
• Inductance (1kHz) LE 1.5mH
• VC Diameter 100mm
• Winding height HVC 22mm
• Winding material Round copper
• Former material Glass fibre

Magnet

• Force factor Bl 22.8N/A
• Motor constant Bl/√RE 9.62N/√W
• Air gap height HAG 10mm
• Weight 3.1kg
• Material Ferrite

Diaphragm

• Effective diameter 380mm
• Effective area SD 1134cm²
• Moving mass MMS 178g
• Moving mass (without air load) MMD 151g
• Material Glass loaded paper (weather-resistant)

Suspensions

• Stiffness KMS 4.35N/mm
• Compliance CMS 230µm/N
• Equivalent volume to the compliance VAS 409L
• Mechanical resistance RMS 5.92N·s/m
• Surround material Cloth-sealed

Dimensions

• Nominal diameter 18″
• 457mm
• Overall diameter 452mm
• Baffle cutout diameter 416mm
• Overall depth 205mm
• Volume occupied by the driver (estimated) 5.8L
• Net weight 9.8kg
• Frame material Cast aluminium