Dayton Audio ND91-4

• Sensitivity (1W, 1m, infinite baffle) SPL1W 82.4dB
• Frequency response 65 - 17000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 74Hz
• Mechanical quality factor QMS 4.24
• Electrical quality factor QES 0.45
• Total quality factor QTS 0.41

Large signal parameters

• Maximum linear excursion xmax 4.6mm
• Air volume displaced at xmax VD 14cm³
• Power handling P 30W
• Program power Pmax 60W

Voice Coil

• Nominal impedance Z 4Ω
• DC resistance RE 4.3Ω
• Inductance (1kHz) LE 0.83mH
• VC Diameter 25mm
• Winding material Aluminum
• Former material Kapton® / Polyimide

Magnet

• Force factor Bl 4.59N/A
• Motor constant Bl/√RE 2.21N/√W
• Material Ferrite

Diaphragm

• Effective diameter 62mm
• Effective area SD 30.4cm²
• Moving mass MMS 4.8g
• Moving mass (without air load) MMD 4.7g
• Material Aluminum

Suspensions

• Stiffness KMS 1.04N/mm
• Compliance CMS 960µm/N
• Equivalent volume to the compliance VAS 1.4L
• Mechanical resistance RMS 0.53N·s/m
• Surround material Rubber

Dimensions

• Nominal diameter 3.5″
• 104mm
• Overall diameter 104mm
• Baffle cutout diameter 85mm
• Overall depth 63mm
• Volume occupied by the driver (estimated) 0.19L
• Frame material Steel