Fostex FF125WK

• Sensitivity (1W, 1m, infinite baffle) SPL1W 89.1dB
• Frequency response 67 - 22000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 67Hz
• Mechanical quality factor QMS 5.09
• Electrical quality factor QES 0.46
• Total quality factor QTS 0.42

Large signal parameters

• Maximum linear excursion xmax 1.7mm
• Air volume displaced at xmax VD 11cm³
• Power handling P 16W
• Program power Pmax 50W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 6.7Ω
• Inductance (1kHz) LE 0.044mH

Magnet

• Force factor Bl 5.6N/A
• Motor constant Bl/√RE 2.16N/√W
• Weight 0.388kg

Diaphragm

• Effective diameter 92mm
• Effective area SD 66cm²
• Moving mass MMS 5g
• Moving mass (without air load) MMD 4.6g

Suspensions

• Stiffness KMS 0.867N/mm
• Compliance CMS 1153µm/N
• Equivalent volume to the compliance VAS 7.27L
• Mechanical resistance RMS 0.41N·s/m

Dimensions

• Nominal diameter 4.5″
• 120mm
• Overall diameter 117mm
• Baffle cutout diameter 104mm
• Overall depth 61mm
• Volume occupied by the driver (estimated) 0.24L
• Net weight 0.92kg