B&C 18SW115 – Ultimate 18″ Neodymium Subwoofer with 3400W Power and 4.5″ Copper Coil

The B&C 18SW115 brings the same 116 mm (4.5-inch) split-winding copper voice coil and 3400 W continuous power handling from B&C’s flagship 21-inch platform down into an 18-inch frame. If you want the hardest-hitting 18-inch sub driver available without stepping up to a 21-inch enclosure, this is the driver that delivers.

With 97 dB sensitivity, 16 mm of linear excursion, and a frequency range from 35 Hz to 1500 Hz, the B&C 18SW115 gives you deep, powerful bass from a driver that fits the most popular subwoofer cabinet format in professional audio. The 18-inch form factor means more enclosure options, more proven cabinet plans, and easier transport than a 21-inch build — with output that challenges many dual-15 and some single-21 configurations.

Available in both 4 Ω and 8 Ω versions, with B&C’s recommended 150-litre enclosure tuned to 35 Hz, the B&C 18SW115 is the 18-inch sub driver for builders who refuse to compromise on power, excursion, or build quality.

Design and Construction of the B&C 18SW115

The B&C 18SW115 shares the same 116 mm (4.5-inch) split-winding copper voice coil found in the 21SW115. This is an enormous coil for an 18-inch driver — many competing 18-inch subs use 100 mm or smaller coils. The larger diameter provides a massive thermal surface area for heat dissipation, which is how the driver sustains 3400 W continuous without compressing or overheating.

Copper winding is a deliberate choice over aluminium. It provides superior thermal conductivity, which means the coil sheds heat more effectively during sustained high-power use. A ventilated voice coil gap allows airflow through the motor during excursion, further reducing power compression. Your sub maintains its full output and punch from the first note to the last.

The double silicone spider suspension provides tight mechanical control over the 275 g moving assembly throughout its 16 mm linear excursion. The 30.3 Tm Bl factor is exceptionally strong, keeping the cone under authoritative motor control even at maximum stroke. You’ll hear tight, defined bass that hits hard and resets fast — no mud, no overhang, no loss of definition at high SPL.

Excursion-optimised lead wires woven through the spider are a detail worth noting. This design prevents lead wire fatigue and breakage during sustained high-excursion operation — a common failure point in lesser drivers pushed to their limits. For builders who plan to drive their sub hard, this is real-world reliability engineering.

An aluminium demodulating ring in the motor structure suppresses modulation distortion, keeping the output clean and linear even under extreme load. The radial cone shape and triple roll surround are optimised for maximum excursion capability with consistent compliance across the stroke.

The cone features TWP (Total Waterproof) treatment on both sides for complete moisture protection. The neodymium inside-slug magnet with T-pole design keeps the motor compact despite its enormous power, holding the total driver weight to 11.9 kg — remarkably light for a 3400 W 18-inch subwoofer.

Performance and Applications for the B&C 18SW115

The B&C 18SW115 handles 3400 W continuous with 97 dB sensitivity — the same power rating and sensitivity as the 21SW115, packaged in a smaller 18-inch frame. The 1.9% reference efficiency and 1210 cm² piston area deliver serious acoustic output from each watt your amplifier provides.

B&C recommends a 150-litre vented enclosure tuned to 35 Hz. That’s a practical, buildable cabinet size that many existing 18-inch sub plans can accommodate. The Qts of 0.30 and EBP of 100 Hz confirm the driver works well in both vented and horn-loaded designs, giving you flexibility depending on your application and output goals.

The 1500 Hz upper frequency limit is notably higher than the 21-inch models’ 1000 Hz, which gives the B&C 18SW115 more versatility. You can use it purely as a sub, or in a two-way configuration where the woofer handles everything up to a higher crossover point before handing off to a compression driver.

Builders commonly choose the B&C 18SW115 for:

• High-power bass-reflex subwoofer cabinets for live sound
• Horn-loaded and bandpass sub designs for maximum SPL
• Festival and touring sub stacks needing sustained extreme output
• Club and venue installations requiring deep, punishing bass
• Two-way full-range cabinets where the 18″ covers LF through midrange

The driver displaces 10.5 litres inside the enclosure — factor this into your net volume calculations. At 242 mm deep and 460 mm overall diameter, the B&C 18SW115 fits standard 18-inch cabinet dimensions while delivering output that punches into 21-inch territory.

Specifications

• Nominal Diameter: 460 mm (18 in)
• Voice Coil Diameter: 116 mm (4.5 in)
• Continuous Power Handling: 3400 W
• Nominal Power Handling: 1700 W
• Nominal Impedance: 8 Ω (also available in 4 Ω)
• Minimum Impedance: 6.5 Ω
• Frequency Range: 35 Hz – 1,500 Hz
• Sensitivity: 97 dB
• Winding Material: Copper (Split Winding)
• Former Material: Glass Fibre
• Winding Depth: 34 mm (1.33 in)
• Magnetic Gap Depth: 14 mm (0.55 in)
• Flux Density: 1.16 T
• Surround Shape: Triple Roll
• Cone Shape: Radial
• Spider: Double Silicone
• Cone Treatment: TWP Waterproof Both Sides

Thiele–Small Parameters

• Fs: 32 Hz
• Re: 5.3 Ω
• Qes: 0.32
• Qms: 5.6
• Qts: 0.30
• Vas: 187 dm³ (6.5 ft³)
• Sd: 1210 cm² (187.6 in²)
• η₀: 1.9%
• Xmax: 14 mm
• Xvar: 16 mm
• Mms: 275 g
• Bl: 30.3 Tm
• Le: 1.9 mH
• EBP: 100 Hz

Mounting Information

• Overall Diameter: 460 mm (18 in)
• Bolt Circle Diameter: 443 mm (17.44 in)
• Baffle Cutout: 422 mm (16.6 in)
• Depth: 242 mm (9.5 in)
• Air Volume Occupied: 10.5 dm³ (0.37 ft³)
• Net Weight: 11.9 kg (26.2 lb)
• Replacement Recone Kit: RCK18SW1158

Conclusion

The B&C 18SW115 puts 21-inch-class power into an 18-inch frame. Its 116 mm split-winding copper coil, 3400 W continuous handling, and 30.3 Tm Bl factor deliver the kind of deep, controlled, physical bass that most 18-inch drivers can only aspire to. The excursion-optimised lead wires and ventilated gap ensure long-term reliability under sustained punishment.

At 11.9 kg with TWP double-side waterproofing, a 150-litre recommended enclosure, and the choice of 4 Ω or 8 Ω impedance, the B&C 18SW115 is the 18-inch sub driver for builders who want the maximum possible output from the most popular subwoofer format in professional audio. If your build needs to shake the floor, the walls, and everything in between, this is the driver that makes it happen.

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About B&C Speakers S.r.L.

B&C Speakers products are built in Bagno a Ripoli (Florence), Italy., ensuring high quality products to suite your speaker building requirements. Their 10,500 square meter facility incorporates highly sophisticated automation and quality control. Over the years they become one of the world leaders in the Professional Audio market, a brand recognized everywhere as a premium product that offers excellent value to the consumer.