Eighteen Sound 21NLW9001 8Ω

• Sensitivity (1W, 1m, infinite baffle) SPL1W 95dB
• Frequency response 25 - 1500Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 32Hz
• Mechanical quality factor QMS 4.50
• Electrical quality factor QES 0.34
• Total quality factor QTS 0.31

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 8Ω
• DC resistance RE 5.9Ω
• Inductance (1kHz) LE 3.1mH
• VC Diameter 135mm

Magnet

• Force factor Bl 37N/A
• Motor constant Bl/√RE 15.2N/√W
• Material Neodymium

Diaphragm

• Effective diameter 460mm
• Effective area SD 1662cm²
• Moving mass MMS 390g
• Moving mass (without air load) MMD 343g
• Material Water,UV repellent

Suspensions

• Stiffness KMS 15.9N/mm
• Compliance CMS 63µm/N
• Equivalent volume to the compliance VAS 244L
• Mechanical resistance RMS 17.4N·s/m

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) 9.1L
• Net weight 13.4kg