SICA 21 S 4 PL

• Sensitivity (1W, 1m, infinite baffle) SPL1W 96.6dB
• Frequency response 35 - 500Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 34.6Hz
• Mechanical quality factor QMS 9.95
• Electrical quality factor QES 0.31
• Total quality factor QTS 0.30

Large signal parameters

• Maximum linear excursion xmax 5.2mm
• Air volume displaced at xmax VD 864cm³
• Power handling P 1200W
• Program power Pmax 2400W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.7Ω
• Inductance (1kHz) LE 1.6mH
• VC Diameter 100mm
• Winding height HVC 17mm
• Winding material Copper
• Former material Glass Fiber

Magnet

• Flux density B 0.89T
• Force factor Bl 36.1N/A
• Motor constant Bl/√RE 15.1N/√W
• Weight 0.536kg
• Material Neodymium

Diaphragm

• Effective diameter 460mm
• Effective area SD 1662cm²
• Moving mass MMS 325g
• Moving mass (without air load) MMD 278g
• Material Paper

Suspensions

• Stiffness KMS 15.4N/mm
• Compliance CMS 65µm/N
• Equivalent volume to the compliance VAS 255L
• Mechanical resistance RMS 7.1N·s/m
• Surround material Treated Cloth

Dimensions

• Nominal diameter 21″
• 545mm
• Overall diameter 545mm
• Baffle cutout diameter 497mm
• Overall depth 249mm
• Volume occupied by the driver (estimated) 7.8L
• Net weight 10.5kg
• Frame material Aluminium Die-Cast