DB Drive WDX18 7KD4

• Sensitivity (1W, 1m, infinite baffle) SPL1W 88.1dB

Thiele & Small parameters

• Resonance frequency (free air) fS 32.6Hz
• Mechanical quality factor QMS 8.84
• Electrical quality factor QES 0.80
• Total quality factor QTS 0.73

Large signal parameters

• Power handling P 3500W
• Program power Pmax 7000W

Voice Coil

• Nominal impedance Z 2 x 4Ω
• DC resistance (in series) RE 6.8Ω
• Inductance (1kHz, in series, estimated) LE 9.2mH

Magnet

• Force factor (in series) Bl 29N/A
• Motor constant Bl/√RE 11.1N/√W

Diaphragm

• Effective diameter 380mm
• Effective area SD 1135cm²
• Moving mass MMS 481g
• Moving mass (without air load) MMD 454g

Suspensions

• Stiffness KMS 20.2N/mm
• Compliance CMS 49.6µm/N
• Equivalent volume to the compliance VAS 90.6L
• Mechanical resistance RMS 11.2N·s/m

Dimensions

• Nominal diameter 18″
• 457mm
• Volume occupied by the driver (estimated) 6.9L