Eighteen Sound 12NMB420

• Sensitivity (1W, 1m, infinite baffle) SPL1W 101.1dB
• Frequency response 55 - 6000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 53Hz
• Mechanical quality factor QMS 3.60
• Electrical quality factor QES 0.30
• Total quality factor QTS 0.28

Large signal parameters

• Maximum linear excursion xmax 4mm
• Air volume displaced at xmax VD 212cm³
• Power handling P 300W
• Program power Pmax 450W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.2Ω
• Inductance (1kHz) LE 0.2mH
• VC Diameter 65mm
• Winding material Aluminum

Magnet

• Force factor Bl 13.9N/A
• Motor constant Bl/√RE 6.1N/√W
• Material Neodymium

Diaphragm

• Effective diameter 260mm
• Effective area SD 531cm²
• Moving mass MMS 33.5g
• Moving mass (without air load) MMD 24.7g
• Material Weather protected

Suspensions

• Stiffness KMS 3.72N/mm
• Compliance CMS 269µm/N
• Equivalent volume to the compliance VAS 105L
• Mechanical resistance RMS 3.1N·s/m

Dimensions

• Nominal diameter 12″
• 300mm
• Overall diameter 315mm
• Baffle cutout diameter 282mm
• Overall depth 127mm
• Flange thickness 11mm
• Mounting depth 116mm
• Volume occupied by the driver (estimated) 1.6L
• Net weight 3.0kg