Eighteen Sound 21NLW4000 8Ω

• Sensitivity (1W, 1m, infinite baffle) SPL1W 94.4dB
• Frequency response 30 - 1800Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 29Hz
• Mechanical quality factor QMS 22.00
• Electrical quality factor QES 0.38
• Total quality factor QTS 0.37

Large signal parameters

• Maximum linear excursion xmax 15mm
• Air volume displaced at xmax VD 2490cm³
• Power handling P 1600W
• Program power Pmax 3200W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 4.9Ω
• Inductance (1kHz) LE 2.8mH
• VC Diameter 100mm
• Winding material Copper

Magnet

• Force factor Bl 30N/A
• Motor constant Bl/√RE 13.6N/√W
• Material Neodymium

Diaphragm

• Effective diameter 460mm
• Effective area SD 1660cm²
• Moving mass MMS 380g
• Moving mass (without air load) MMD 333g
• Material Water,UV repellent

Suspensions

• Stiffness KMS 12.7N/mm
• Compliance CMS 79µm/N
• Equivalent volume to the compliance VAS 305L
• Mechanical resistance RMS 3.15N·s/m

Dimensions

• Nominal diameter 21″
• 533mm
• Overall diameter 545mm
• Baffle cutout diameter 492mm
• Overall depth 245mm
• Flange thickness 18mm
• Mounting depth 227mm
• Volume occupied by the driver (estimated) 8.2L
• Net weight 11.6kg