Hertz SX 250D

• Sensitivity (1W, 1m, infinite baffle) SPL1W 87.7dB
• Frequency response 34 - 800Hz

Thiele & Small parameters

• Resonance frequency (free air) fS 51Hz
• Mechanical quality factor QMS 8.00
• Electrical quality factor QES 0.44
• Total quality factor QTS 0.42

Large signal parameters

• Maximum linear excursion xmax 14mm
• Air volume displaced at xmax VD 503cm³
• Power handling P 600W
• Program power Pmax 2400W

Voice Coil

• Nominal impedance Z 2 x 2Ω
• DC resistance (in series) RE 4.0Ω
• Inductance (1kHz, in series, estimated) LE 2.46mH
• VC Diameter 65mm

Magnet

• Force factor (in series) Bl 20.8N/A
• Motor constant Bl/√RE 10.4N/√W
• Material Double magnet, High density flux ferrite

Diaphragm

• Effective diameter 210mm
• Effective area SD 360cm²
• Moving mass MMS 147g
• Moving mass (without air load) MMD 142g
• Material Pressed paper

Suspensions

• Stiffness KMS 16.7N/mm
• Compliance CMS 60µm/N
• Equivalent volume to the compliance VAS 11L
• Mechanical resistance RMS 5.89N·s/m

Dimensions

• Nominal diameter 10″
• 250mm
• Volume occupied by the driver (estimated) 1.5L