Dayton Audio Ultimax II UMII8-22

• Sensitivity (1W, 1m, infinite baffle) SPL1W 81.3dB
• Frequency response 30 - 600Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 46Hz
• Mechanical quality factor QMS 3.10
• Electrical quality factor QES 0.99
• Total quality factor QTS 0.75

Large signal parameters

• Maximum linear excursion xmax 18mm
• Air volume displaced at xmax VD 360cm³
• Power handling P 400W
• Program power Pmax 800W

Voice Coil

• Nominal impedance Z 2 x 2Ω
• DC resistance (in series) RE 3.9Ω
• Inductance (1kHz, in series) LE 0.75mH
• VC Diameter 63.5mm

Magnet

• Force factor (in series) Bl 9.7N/A
• Motor constant Bl/√RE 4.91N/√W
• Material Ferrite

Diaphragm

• Effective diameter 160mm
• Effective area SD 200cm²
• Moving mass MMS 82g
• Moving mass (without air load) MMD 80.1g
• Material Carbon Fiber

Suspensions

• Stiffness KMS 6.76N/mm
• Compliance CMS 148µm/N
• Equivalent volume to the compliance VAS 8.4L
• Mechanical resistance RMS 7.65N·s/m
• Surround material Rubber

Dimensions

• Nominal diameter 8″
• 185mm
• Overall diameter 185mm
• Baffle cutout diameter 145mm
• Overall depth 144mm
• Volume occupied by the driver (estimated) 1.2L
• Frame material Cast Aluminium