Dayton Audio ND140-4

• Sensitivity (1W, 1m, infinite baffle) SPL1W 84.7dB
• Frequency response 54 - 8000Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 59.2Hz
• Mechanical quality factor QMS 5.35
• 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 35cm³
• Power handling P 40W
• Program power Pmax 80W

Voice Coil

• Nominal impedance Z 4Ω
• DC resistance RE 3.7Ω
• Inductance (1kHz) LE 0.79mH
• VC Diameter 25.4mm
• Former material Kapton Polyimide

Magnet

• Force factor Bl 3.9N/A
• Motor constant Bl/√RE 2.03N/√W
• Material Neodymium

Diaphragm

• Effective diameter 105mm
• Effective area SD 86.6cm²
• Moving mass MMS 10.1g
• Moving mass (without air load) MMD 9.5g
• Material Black Anodized Aluminum

Suspensions

• Stiffness KMS 1.41N/mm
• Compliance CMS 710µm/N
• Equivalent volume to the compliance VAS 7.22L
• Mechanical resistance RMS 0.7N·s/m
• Surround material Rubber

Dimensions

• Nominal diameter 5.25″
• 138mm
• Overall diameter 138mm
• Baffle cutout diameter 120mm
• Overall depth 71mm
• Volume occupied by the driver (estimated) 0.32L