Fostex P650K

• Sensitivity (1W, 1m, infinite baffle) SPL1W 83.1dB
• Frequency response 157 - 20000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 157Hz
• Mechanical quality factor QMS 3.39
• Electrical quality factor QES 1.40
• Total quality factor QTS 0.99

Large signal parameters

• Maximum linear excursion xmax 0.5mm
• Air volume displaced at xmax VD 1.1cm³
• Power handling P 5W
• Program power Pmax 15W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 7.3Ω
• Inductance (1kHz) LE 0.25mH
• VC Diameter 20mm

Magnet

• Force factor Bl 3.06N/A
• Motor constant Bl/√RE 1.13N/√W
• Weight 0.074kg

Diaphragm

• Effective diameter 52mm
• Effective area SD 21cm²
• Moving mass MMS 1.8g
• Moving mass (without air load) MMD 1.7g

Suspensions

• Stiffness KMS 1.74N/mm
• Compliance CMS 576µm/N
• Equivalent volume to the compliance VAS 0.35L
• Mechanical resistance RMS 0.52N·s/m

Dimensions

• Nominal diameter 2.6″
• 65mm
• Overall diameter 65mm
• Baffle cutout diameter 60mm
• Overall depth 38mm
• Net weight 0.249kg