Vintage EMINENCE 18" 18456 4ohm Cast Woofer Speaker Driver TESTED

Condition is GREAT, tested and working, pulled from a working environment. Shipped USPS for FREE the very same day you order to make sure you get it FAST. If you have any issues with this item at all please just me a message immediately, before leaving feedback, and I promise to solve it whether that means a full refund or a replacement. Whatever the case, I’m here to make sure your experience ordering from me goes well.

If you have any issues with this item at all please just me a message immediately, before leaving feedback, and I promise to solve it whether that means a full refund or a replacement. Whatever the case, I’m here to make sure your experience ordering from me goes well.

cast-frame professional woofer/subwoofer driver, most commonly identified as (or a close variant/recone match for) the Eminence Sigma Pro 18-4 (or related Sigma Pro 18 series 4-ohm model). 

It is a high-efficiency, high-value pro audio woofer designed primarily for vented enclosures (also suitable for horn loading or scoops in some applications). It features a robust die-cast aluminum basket/frame, large ferrite magnet, and is built for high-power bass performance in PA, DJ, subwoofer, or bass guitar cabinets. The “TESTED” in listings typically indicates it has been functionally checked (e.g., voice coil continuity, no rubs, etc.). 

Key Specifications (Sigma Pro 18-4 / 18456 4Ω variant)

• Nominal Diameter: 18” (457 mm)

• Nominal Impedance: 4 Ω (DC Resistance Re ≈ 3.35–3.4 Ω)

• Power Rating: 700 W RMS / 1400 W Program (music/program power)

• Resonance Frequency (Fs): 32 Hz

• Usable Frequency Range: ~32 Hz – 2 kHz (or up to ~2.4 kHz in some related models)

• Sensitivity: ~97.1–97.6 dB (1W/1m)

• Voice Coil: 3” (76 mm) diameter, copper winding on polyimide (Kapton) former

• Magnet: Ferrite, ~120 oz (heavy ceramic magnet for strong motor strength)

• Gap Height: 0.375” (9.5 mm)

• Xmax (linear excursion, one-way): ~7 mm

• Xlim (mechanical limit): ~18 mm

• Sd (Cone Area): 1140 cm²

• Vas: ~361 liters (12.74 cu.ft.)

• Qts: ~0.29

• Mms: ~121 g

• BL: ~16.5 T·m

Mounting/Dimensions:

• Overall Diameter: 18” (457.2 mm)

• Baffle Cutout: ~16.56” (420–421 mm)

• Depth: 8.15” (207 mm)

• Mounting Holes: 8 holes on 17.25” B.C.D. (0.28” / 7.1 mm diameter)

• Net Weight: ~24.5 lbs (11.11 kg); Shipping ~28 lbs

• Recommended Vented Enclosure: ~3–7.5 cu.ft. (85–212 liters) depending on tuning and application. 

Materials/Construction:

• Die-cast aluminum basket (cast frame for rigidity and heat dissipation).

• Paper cone with cloth surround (edge).

• Solid composition paper dust cap.

• Vented and extended core/pole piece for improved power handling and cooling.

• Polyimide former for thermal stability.