Celestion TF1225

• Sensitivity (1W, 1m, infinite baffle) SPL1W 95.4dB
• Frequency response 50 - 4000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 55.6Hz
• Mechanical quality factor QMS 3.11
• Electrical quality factor QES 0.42
• Total quality factor QTS 0.37

Large signal parameters

• Maximum linear excursion xmax 4.5mm
• Air volume displaced at xmax VD 239cm³
• Power handling P 250W
• Program power Pmax 500W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.1Ω
• Inductance (1kHz) LE 0.86mH
• VC Diameter 64mm
• Winding height HVC 13mm
• Winding material Round copper
• Former material Polyimide

Magnet

• Force factor Bl 14.3N/A
• Motor constant Bl/√RE 6.35N/√W
• Air gap height HAG 8mm
• Weight 1.2kg
• Material Ferrite

Diaphragm

• Effective diameter 260mm
• Effective area SD 531cm²
• Moving mass MMS 48.5g
• Moving mass (without air load) MMD 39.9g
• Material Kevlar loaded paper

Suspensions

• Stiffness KMS 5.88N/mm
• Compliance CMS 170µm/N
• Equivalent volume to the compliance VAS 67.3L
• Mechanical resistance RMS 5.45N·s/m
• Surround material Cloth-sealed

Dimensions

• Nominal diameter 12″
• 305mm
• Overall diameter 309mm
• Baffle cutout diameter 283mm
• Overall depth 130mm
• Volume occupied by the driver (estimated) 1.9L
• Net weight 4.1kg
• Frame material Pressed steel