Dayton Audio ND91-8

• Sensitivity (1W, 1m, infinite baffle) SPL1W 81.6dB
• Frequency response 70 - 17000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 70.7Hz
• Mechanical quality factor QMS 4.29
• Electrical quality factor QES 0.53
• Total quality factor QTS 0.47

Large signal parameters

• Maximum linear excursion xmax 5.1mm
• Air volume displaced at xmax VD 16cm³
• Power handling P 30W
• Program power Pmax 60W

Voice Coil

• Nominal impedance Z 8Ω
• DC resistance RE 7.8Ω
• Inductance (1kHz) LE 1.24mH
• VC Diameter 25mm
• Winding material Aluminum
• Former material Kapton® / Polyimide

Magnet

• Force factor Bl 5.63N/A
• Motor constant Bl/√RE 2.02N/√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 0.952N/mm
• Compliance CMS 1050µm/N
• Equivalent volume to the compliance VAS 1.53L
• Mechanical resistance RMS 0.5N·s/m
• Surround material Rubber

Dimensions

• Nominal diameter 3.5″
• 104mm
• Overall diameter 104mm
• Baffle cutout diameter 85mm
• Overall depth 56mm
• Volume occupied by the driver (estimated) 0.16L
• Frame material Steel