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DELTA PRO-18A
SPECIFICATION
Nominal Basket Diameter 18'', 457mm
Nominal Impedance* 8 ohms
Power Rating
Watts 500W
Music Program 1000W
Resonance 28Hz
Usable Frequency Range 37Hz-250Hz
Sensitivity*** 96
Magnet Weight 67 oz.
Gap Height 0.380'', 9.53mm
Voice Coil Diameter 2.5'', 63.5mm

THIELE & SMALL PARAMETERS
Resonant Frequency (fs) 28Hz
DC Resistance (Re) 5.3
Coil Inductance (Le) 3.43mH
Mechanical Q (Qms) 10.38
Electromagnetic Q (Qes) 0.33
Total Q (Qts) 0.32
Compliance Equivalent Volume (Vas) 493.2 liters / 17.41cu.ft.
Peak Diaphragm Displacement Volume (Vd) 796cc
Mechanical Compliance of Suspension (Cms) 0.25mm/N
BL Product (BL) 18.9 T-M
Diaphram Mass inc. Airload (Mms) 128 grams
Efficiency Bandwidth Product (EBP) 84
Maximum Linear Excursion (Xmax) 6.7mm
Surface Area of Cone (Sd) 1188.0 cm2
Maximum Mechanical Limit (Xlim) 15.0mm

MOUNTING INFORMATION
Recommended Enclosure
Sealed N/A
Vented 85-297 liters/3.0-10.5 cu.ft.
Overall Diameter 18.00'', 457.2mm
Baffle Hole Diameter 16.57'', 420.9mm
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 8.13'', 207mm
Net Weight 17.0 lbs, 7.7 kg
Shipping Weight 20.5 lbs, 9.3 kg

MATERIALS 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 aluminum basket
Cone Composition Paper cone
Cone Edge Composition Cloth cone edge
Dustcap Composition Solid composition paper dust cap