Eighteen Sound 8M400

• Sensitivity (1W, 1m, infinite baffle) SPL1W 97.2dB
• Frequency response 120 - 6100Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 90Hz
• Mechanical quality factor QMS 6.20
• Electrical quality factor QES 0.28
• Total quality factor QTS 0.27

Large signal parameters

• Maximum linear excursion xmax 3mm
• Maximum excursion before damage xlim 6.5mm
• Air volume displaced at xmax VD 68cm³
• Power handling P 250W
• Program power Pmax 320W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.2Ω
• Inductance (1kHz) LE 0.95mH
• VC Diameter 51mm
• Winding material Aluminum

Magnet

• Force factor Bl 12.2N/A
• Motor constant Bl/√RE 5.35N/√W
• Material Ferrite

Diaphragm

• Effective diameter 170mm
• Effective area SD 227cm²
• Moving mass MMS 14g
• Moving mass (without air load) MMD 11.5g
• Material Curvilinear, Paper

Suspensions

• Stiffness KMS 4.51N/mm
• Compliance CMS 222µm/N
• Equivalent volume to the compliance VAS 16.2L
• Mechanical resistance RMS 1.28N·s/m
• Surround material M-roll, Polycotton

Dimensions

• Nominal diameter 8″
• 200mm
• Overall diameter 210mm
• Baffle cutout diameter 184mm
• Overall depth 106mm
• Flange thickness 15mm
• Mounting depth 91mm
• Volume occupied by the driver (estimated) 1.4L
• Net weight 4.5kg