Eighteen Sound 6NMB420

• Sensitivity (1W, 1m, infinite baffle) SPL1W 95.8dB
• Frequency response 200 - 7000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 110Hz
• Mechanical quality factor QMS 2.70
• Electrical quality factor QES 0.38
• Total quality factor QTS 0.33

Large signal parameters

• Maximum linear excursion xmax 3mm
• Air volume displaced at xmax VD 39cm³
• Power handling P 200W
• Program power Pmax 260W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.3Ω
• Inductance (1kHz) LE 0.1mH
• VC Diameter 44mm
• Winding material Aluminum

Magnet

• Force factor Bl 9N/A
• Motor constant Bl/√RE 3.91N/√W
• Material Neodymium

Diaphragm

• Effective diameter 129mm
• Effective area SD 130cm²
• Moving mass MMS 8.5g
• Moving mass (without air load) MMD 7.4g
• Material Weather protected

Suspensions

• Stiffness KMS 4.07N/mm
• Compliance CMS 246µm/N
• Equivalent volume to the compliance VAS 6.1L
• Mechanical resistance RMS 2.18N·s/m

Dimensions

• Nominal diameter 6.5″
• 152mm
• Overall diameter 162mm
• Baffle cutout diameter 148mm
• Overall depth 73mm
• Flange thickness 11mm
• Mounting depth 62mm
• Volume occupied by the driver (estimated) 0.41L
• Net weight 1.25kg