Dayton Audio Ultimax UM8-22

• Sensitivity (1W, 1m, infinite baffle) SPL1W 80.8dB
• Frequency response 30 - 800Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 34.3Hz
• Mechanical quality factor QMS 2.47
• Electrical quality factor QES 0.87
• Total quality factor QTS 0.64

Large signal parameters

• Maximum linear excursion xmax 16mm
• Air volume displaced at xmax VD 338cm³
• Power handling P 300W
• Program power Pmax 600W

Voice Coil

• Nominal impedance Z 2 x 2Ω
• DC resistance (in series) RE 4.2Ω
• Inductance (1kHz, in series) LE 0.73mH
• VC Diameter 50.8mm
• Winding material Copper
• Former material Aluminum

Magnet

• Force factor (in series) Bl 9.2N/A
• Motor constant Bl/√RE 4.49N/√W
• Material Ferrite

Diaphragm

• Effective diameter 164mm
• Effective area SD 211cm²
• Moving mass MMS 81.2g
• Moving mass (without air load) MMD 78.9g
• Material Nomex

Suspensions

• Stiffness KMS 3.7N/mm
• Compliance CMS 270µm/N
• Equivalent volume to the compliance VAS 16.6L
• Mechanical resistance RMS 7.08N·s/m
• Surround material Rubber

Dimensions

• Nominal diameter 8″
• 210mm
• Overall diameter 210mm
• Baffle cutout diameter 189mm
• Overall depth 120mm
• Volume occupied by the driver (estimated) 1.1L
• Frame material Cast Aluminium