Specification:
Nominal Basket Diameter 18", 457.2mm
Nominal Impedance* 4 ohms
Power Rating**
Watts 1200W
Music Program 2400W
Resonance 31.48Hz
Usable Frequency Range 36Hz - 0.82kHz
Sensitivity*** 94.5dB
Magnet Weight 109 oz.
Gap Height 0.5", 12.7mm
Voice Coil Diameter 4", 101.6mm

Thiele & Small Parameters
Resonant Frequency (fs) 31.48Hz
DC Resistance (Re) 3.13
Coil Inductance (Le) 1.09mH
Mechanical Q (Qms) 10.13
Electromagnetic Q (Qes) 0.35
Total Q (Qts) 0.34
Compliance Equivalent Volume (Vas) 317.02 liters / 11.19 cu.ft.
Peak Diaphragm Displacement Volume (Vd) 942.7cc
Mechanical Compliance of Suspension (Cms) 0.17mm/N
BL Product (BL) 16.1 T-M
Diaphragm Mass Inc. Airload (MMs) 147.56 grams
Efficiency Bandwidth Product (EBP) 89.48
Maximum Linear Excursion (Xmax) 8.13mm
Surface Area of Cone (Sd) 1159 cm2
Maximum Mechanical Limit (Xlim) 20.1mm
Mounting Information
Recommended Enclosure Volume
Sealed N/a
Vented 118.9-339.8 liters / 4.2-12 cu.ft.
Driver Volume Displaced 409.6 cu.in. / 6.7 liters
Overall Diameter 18", 457.2mm
Baffle Hole Diameter 16.56", 420.62mm
Front Sealing Gasket Fitted as standard
Rear Sealing Gasket Fitted as standard
Mounting Holes Diameter 0.29", 7.36mm
Mounting Holes B.C.D. 17.25", 438.1mm
Depth 8.31", 211.07mm
Net Weight 27.3 lbs, 12.3 kg
Shipping Weight 30.8 lbs, 13.9 kgs
Materials of Construction
Coil Construction Copper voice coil
Coil Former Fiberglass
Magnet Composition Ferrite magnet
Core Details Bumped Vented Extended core

Basket Materials Die-cast aluminum basket
Cone Composition Water Resistant Treated Paper Cone
Cone Edge Composition Treated Cloth cone edge
Dust Cap Composition Water Resistant Treated Paper dust cap