Eighteen Sound 18iD

• Sensitivity (1W, 1m, infinite baffle) SPL1W 94.1dB
• Frequency response 30 - 2500Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 40Hz
• Mechanical quality factor QMS 5.50
• Electrical quality factor QES 0.27
• Total quality factor QTS 0.26

Large signal parameters

• Maximum linear excursion xmax 15.5mm
• Air volume displaced at xmax VD 1899cm³
• Power handling P 1800W
• Program power Pmax 3600W

Voice Coil

• Nominal impedance Z 2Ω
• DC resistance RE 1.5Ω
• Inductance (1kHz) LE 1.22mH
• VC Diameter 135mm
• Winding material Copper

Magnet

• Force factor Bl 24N/A
• Motor constant Bl/√RE 19.6N/√W
• Material Neodymium

Diaphragm

• Effective diameter 395mm
• Effective area SD 1225cm²
• Moving mass MMS 420g
• Moving mass (without air load) MMD 390g
• Material Water,UV repellent

Suspensions

• Stiffness KMS 26.3N/mm
• Compliance CMS 38µm/N
• Equivalent volume to the compliance VAS 67L
• Mechanical resistance RMS 19.2N·s/m

Dimensions

• Nominal diameter 18″
• 460mm
• Overall diameter 462mm
• Baffle cutout diameter 416mm
• Overall depth 236mm
• Flange thickness 26mm
• Mounting depth 210mm
• Volume occupied by the driver (estimated) 7.6L
• Net weight 12.5kg