Eighteen Sound 8NMB420 8Ω

• Sensitivity (1W, 1m, infinite baffle) SPL1W 96dB
• Frequency response 60 - 5500Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 61Hz
• Mechanical quality factor QMS 4.00
• Electrical quality factor QES 0.31
• Total quality factor QTS 0.28

Large signal parameters

• Maximum linear excursion xmax 5.8mm
• Air volume displaced at xmax VD 133cm³
• Power handling P 280W
• Program power Pmax 400W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.0Ω
• Inductance (1kHz) LE 0.35mH
• VC Diameter 51mm

Magnet

• Force factor Bl 10N/A
• Motor constant Bl/√RE 4.47N/√W
• Material Neodymium

Diaphragm

• Effective diameter 171mm
• Effective area SD 230cm²
• Moving mass MMS 14.9g
• Moving mass (without air load) MMD 12.4g

Suspensions

• Stiffness KMS 2.19N/mm
• Compliance CMS 457µm/N
• Equivalent volume to the compliance VAS 33L
• Mechanical resistance RMS 1.43N·s/m

Dimensions

• Nominal diameter 8″
• 200mm
• Overall diameter 210mm
• Baffle cutout diameter 186mm
• Overall depth 99mm
• Flange thickness 14mm
• Mounting depth 85mm
• Volume occupied by the driver (estimated) 0.72L
• Net weight 1.7kg