Eighteen Sound 18iDSDS

• Sensitivity (1W, 1m, infinite baffle) SPL1W 94.4dB
• Frequency response 29 - 1000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 29Hz
• Mechanical quality factor QMS 7.00
• Electrical quality factor QES 0.18
• Total quality factor QTS 0.17

Large signal parameters

• Maximum linear excursion xmax 18mm
• Air volume displaced at xmax VD 2205cm³
• Power handling P 1800W
• Program power Pmax 3600W

Voice Coil

• Nominal impedance Z 2Ω
• DC resistance RE 1.3Ω
• Inductance (1kHz) LE 0.93mH
• VC Diameter 135mm
• Winding height HVC 45mm
• Winding material Aluminum

Magnet

• Force factor Bl 24.4N/A
• Motor constant Bl/√RE 21.4N/√W
• Air gap height HAG 18mm
• Material Neodymium

Diaphragm

• Effective diameter 395mm
• Effective area SD 1225cm²
• Moving mass MMS 444g
• Moving mass (without air load) MMD 414g
• Material Reinforced, water repellent

Suspensions

• Stiffness KMS 14.7N/mm
• Compliance CMS 68µm/N
• Equivalent volume to the compliance VAS 136L
• Mechanical resistance RMS 11.6N·s/m
• Spider material Double Silicon

Dimensions

• Nominal diameter 18″
• 462mm
• Overall diameter 462mm
• Baffle cutout diameter 417mm
• Overall depth 238mm
• Flange thickness 24mm
• Mounting depth 214mm
• Volume occupied by the driver (estimated) 8.9L
• Net weight 16.0kg