BMS 18N840

• Sensitivity (1W, 1m, infinite baffle) SPL1W 94dB
• Frequency response 20 - 200Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 30.2Hz
• Mechanical quality factor QMS 6.30
• Electrical quality factor QES 0.40
• Total quality factor QTS 0.37

Large signal parameters

• Maximum linear excursion xmax 10mm
• Air volume displaced at xmax VD 1213cm³
• Power handling P 1200W
• Program power Pmax 2400W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.0Ω
• Inductance (1kHz) LE 0.87mH
• VC Diameter 101.6mm
• Winding height HVC 32mm
• Winding material Copper

Magnet

• Force factor Bl 23N/A
• Motor constant Bl/√RE 10.3N/√W
• Air gap height HAG 12mm

Diaphragm

• Effective diameter 393mm
• Effective area SD 1213cm²
• Moving mass MMS 222g
• Moving mass (without air load) MMD 193g

Suspensions

• Stiffness KMS 8N/mm
• Compliance CMS 125µm/N
• Equivalent volume to the compliance VAS 261L
• Mechanical resistance RMS 6.69N·s/m

Dimensions

• Nominal diameter 18″
• 458mm
• Overall diameter 458mm
• Baffle cutout diameter 414mm
• Overall depth 237mm
• Volume occupied by the driver (estimated) 6.5L
• Net weight 9.8kg
• Frame material Cast Aluminum