Fostex FF85WK

• Sensitivity (1W, 1m, infinite baffle) SPL1W 86dB
• Frequency response 115 - 28000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 115Hz
• Mechanical quality factor QMS 3.30
• Electrical quality factor QES 0.68
• Total quality factor QTS 0.55

Large signal parameters

• Maximum linear excursion xmax 0.4mm
• Air volume displaced at xmax VD 1cm³
• Power handling P 5W
• Program power Pmax 15W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 7.2Ω
• Inductance (1kHz) LE 0.032mH
• VC Diameter 16mm

Magnet

• Force factor Bl 3.93N/A
• Motor constant Bl/√RE 1.46N/√W
• Weight 0.187kg

Diaphragm

• Effective diameter 60mm
• Effective area SD 28cm²
• Moving mass MMS 2g
• Moving mass (without air load) MMD 1.9g

Suspensions

• Stiffness KMS 1.1N/mm
• Compliance CMS 909µm/N
• Equivalent volume to the compliance VAS 1.04L
• Mechanical resistance RMS 0.44N·s/m

Dimensions

• Nominal diameter 3.2″
• 80mm
• Overall diameter 83mm
• Baffle cutout diameter 73mm
• Overall depth 47mm
• Volume occupied by the driver (estimated) 0.1L
• Net weight 0.45kg