Dayton Audio ND90-4

• Sensitivity (1W, 1m, infinite baffle) SPL1W 82.4dB
• Frequency response 80 - 15000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 90.2Hz
• Mechanical quality factor QMS 5.10
• Electrical quality factor QES 0.72
• Total quality factor QTS 0.63

Large signal parameters

• Maximum linear excursion xmax 4mm
• Air volume displaced at xmax VD 13cm³
• Power handling P 20W
• Program power Pmax 40W

Voice Coil

• Nominal impedance Z 4Ω
• DC resistance RE 3.6Ω
• Inductance (1kHz) LE 0.62mH
• VC Diameter 19mm
• Winding material Copper
• Former material Kapton® / Polyimide

Magnet

• Force factor Bl 3.47N/A
• Motor constant Bl/√RE 1.83N/√W
• Material Neodymium

Diaphragm

• Effective diameter 63mm
• Effective area SD 31.2cm²
• Moving mass MMS 4.3g
• Moving mass (without air load) MMD 4.1g
• Material Black Anodized Aluminum

Suspensions

• Stiffness KMS 1.37N/mm
• Compliance CMS 730µm/N
• Equivalent volume to the compliance VAS 1.06L
• Mechanical resistance RMS 0.48N·s/m
• Surround material Rubber

Dimensions

• Nominal diameter 3.5″
• 104mm
• Overall diameter 104mm
• Baffle cutout diameter 85mm
• Overall depth 61mm
• Volume occupied by the driver (estimated) 0.18L
• Frame material Steel