FEATURES:SPECIFICATION [ Nominal Basket Diameter 18"", 457.2mm [ Nominal Impedance* 8 ohms [ Power Rating: Watts 650, Music Program: 1300 W[ Resonance: 28Hz [ Usable Frequency Range: 41Hz-2.4Hz [ Sensitivity: 99[ Magnet Weight: 120 oz. [ Gap Height 0.375"", 9.53mm [ Voice Coil Diameter: 3"", 76.2mm THIELE & SMALL PARAMETERS [ Resonant Frequency (fs): 28Hz [ DC Resistance (Re): 6.29[ Coil Inductance (Le): 1.9mH [ Mechanical Q (Qms): 8.28[ Electromagnetic Q (Qes): 0.30[ Total Q (Qts): 0.29[ Compliance Equivalent Volume (Vas): 441.2 liters / 15.6 cu. ft.[ Peak Diaphragm Displacement Volume (Vd): 695cc [ Mechanical Compliance of Suspension (Cms): 0.24mm/N [ BL Product (BL): 22.1 T-M [ Diaphragm Mass inc. Airload (Mms): 130 grams [ Efficiency Bandwidth Product (EBP): 93 [ Maximum Linear Excursion (Xmax) 6.1mm [ Surface Area of Cone (Sd): 1140 cm² [ Maximum Mechanical Limit (Xlim): 18mm MOUNTING INFORMATION [ Recommended Enclosure: Sealed: - /Vented: 93-212 liters/3.3-7.5 cu.ft.[ Overall Diameter: 18"", 457.2mm[ Baffle Hole Diameter: 16.56"", 420.5mm[ Front Sealing Gasket: fitted as standard [ Rear Sealing Gasket: fitted as standard [ Mounting Holes Diameter: 0.28"", 7.1mm[ Mounting Holes B.C. D.: 17.25"", 438.2mm[ Depth: 8.15"", 207mm[ Shipping Weight: 24.5 lbs., 11.1 kg[ Shipping Weight 28.1 lbs., 12.8 kgMATERIALS OF CONSTRUCTION [ Coil Construction: Copper voice coil [ Coil Former: Polyimide former [ Magnet Composition: Ferrite magnet [ Core Details: Vented and Extended core [ Basket Materials: Die-cast aluminium basket[ Cone Composition Paper Cone [ Cone Edge Composition: Cloth cone edge [ Dustcap Composition: Solid composition paper dust cap ";
