DB Drive Speed SPF12D4

• Sensitivity (1W, 1m, infinite baffle) SPL1W 85.7dB

Thiele & Small parameters

• Resonance frequency (free air) fS 23.2Hz
• Mechanical quality factor QMS 5.80
• Electrical quality factor QES 0.58
• Total quality factor QTS 0.53

Large signal parameters

• Power handling P 300W
• Program power Pmax 1000W

Voice Coil

• Nominal impedance Z 2 x 4Ω
• DC resistance (in series) RE 7.2Ω
• Inductance (1kHz, in series, estimated) LE 4.96mH
• VC Diameter 63.5mm
• Former material Aluminum

Magnet

• Force factor (in series) Bl 17.7N/A
• Motor constant Bl/√RE 6.61N/√W
• Material Ferrite

Diaphragm

• Effective diameter 265mm
• Effective area SD 552cm²
• Moving mass MMS 174g
• Moving mass (without air load) MMD 165g

Suspensions

• Stiffness KMS 3.7N/mm
• Compliance CMS 270µm/N
• Equivalent volume to the compliance VAS 117L
• Mechanical resistance RMS 4.38N·s/m
• Surround material Foam

Dimensions

• Nominal diameter 12″
• 304mm
• Overall diameter 315mm
• Baffle cutout diameter 284mm
• Mounting depth 89mm
• Volume occupied by the driver (estimated) 2.6L
• Frame material Steel