Celestion NTR21-5010JD

• Sensitivity (1W, 1m, infinite baffle) SPL1W 95.5dB
• Frequency response 30 - 3000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 32.2Hz
• Mechanical quality factor QMS 5.82
• Electrical quality factor QES 0.34
• Total quality factor QTS 0.32

Large signal parameters

• Maximum linear excursion xmax 9mm
• Air volume displaced at xmax VD 1496cm³
• Power handling P 1600W
• Program power Pmax 3200W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 5.6Ω
• Inductance (1kHz) LE 2.25mH
• VC Diameter 125mm
• Winding height HVC 30mm
• Winding material Round copper
• Former material Glass fibre

Magnet

• Force factor Bl 33.9N/A
• Motor constant Bl/√RE 14.3N/√W
• Air gap height HAG 12mm
• Material Neodymium

Diaphragm

• Effective diameter 460mm
• Effective area SD 1662cm²
• Moving mass MMS 344g
• Moving mass (without air load) MMD 296g
• Material Carbon fibre loaded paper

Suspensions

• Stiffness KMS 14.3N/mm
• Compliance CMS 70µm/N
• Equivalent volume to the compliance VAS 277L
• Mechanical resistance RMS 12N·s/m
• Surround material Cloth-sealed

Dimensions

• Nominal diameter 21″
• 530mm
• Overall diameter 550mm
• Baffle cutout diameter 492mm
• Overall depth 254mm
• Volume occupied by the driver (estimated) 9L
• Net weight 12.8kg
• Frame material Cast aluminium