Eighteen Sound 21NLW9601

• Sensitivity (1W, 1m, infinite baffle) SPL1W 95.9dB
• Frequency response 31 - 1800Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 41Hz
• Mechanical quality factor QMS 10.56
• Electrical quality factor QES 0.33
• Total quality factor QTS 0.32

Large signal parameters

• Maximum linear excursion xmax 14mm
• Air volume displaced at xmax VD 2327cm³
• Power handling P 1800W
• Program power Pmax 3600W

Voice Coil

• Nominal impedance Z 4Ω
• DC resistance RE 3.0Ω
• Inductance (1kHz) LE 2.18mH
• VC Diameter 135mm
• Winding material Copper

Magnet

• Force factor Bl 32.7N/A
• Motor constant Bl/√RE 18.9N/√W
• Material Neodymium

Diaphragm

• Effective diameter 460mm
• Effective area SD 1662cm²
• Moving mass MMS 450g
• Moving mass (without air load) MMD 403g
• Material Weather protected

Suspensions

• Stiffness KMS 30.3N/mm
• Compliance CMS 33µm/N
• Equivalent volume to the compliance VAS 123L
• Mechanical resistance RMS 11N·s/m
• Spider material Triple silicon

Dimensions

• Nominal diameter 21″
• 533mm
• Overall diameter 545mm
• Baffle cutout diameter 492mm
• Overall depth 250mm
• Flange thickness 18mm
• Mounting depth 232mm
• Volume occupied by the driver (estimated) 9.2L
• Net weight 13.5kg