B&C Speakers 21 SW 152 4 Ohms

A 21" B&C Driver Focused on Infra-Bass, for Cabinets That "Push Air"

Within a range where each model targets a specific application, the B&C 21SW152 positions itself as a very large diameter speaker intended for reproducing low and infra-low frequencies with a clear goal: to generate output level and air displacement while maintaining a usable response in a properly designed enclosure. Featuring a neodymium magnet and a 6.0" voice coil, it belongs to the category of transducers designed for current sound reinforcement systems where available power and bass demand are high.

Who Is It For and What Are Its Uses?

This 21" driver is aimed at integrators, cabinet builders, professionals, and demanding enthusiasts seeking a serious solution for an infra subwoofer cabinet. It is particularly relevant for live sound reinforcement, clubs, high SPL fixed installations, or any system requiring a solid foundation beneath the low-midrange. With its rated sensitivity of 96dB 1W/1m and frequency range of 30Hz - 1kHz, it can be considered in architectures where filtering and acoustic loading are optimized to fully exploit the bass register.

The manufacturer's recommendation of 190 liters with a 33Hz tuning provides clear guidance: this speaker performs best in substantial enclosure volumes typical of 21" infra-oriented cabinets. It is a coherent choice if your priority is foundation, impact, and depth rather than a compact cabinet.

Design and Key Points for Performance

6.0" Voice Coil and AES Power: Endure Long-Term, Stay Stable

The combination of a 6.0" (153mm) copper wire voice coil with a 4000W AES power rating emphasizes the ability to handle sustained operation. In subwoofer use, thermal endurance and behavioral stability are critical: a large diameter voice coil helps better manage heat buildup and maintain reliable response when the system is driven over extended periods.

Neodymium Motor: Flux Density and Weight Control

The neodymium magnet enables a powerful motor while keeping mass contained. With a listed weight of 18.5kg, the 21SW152 remains practical for applications where handling, installation, and logistics matter, without sacrificing the performance ambitions expected from a high-power 21" driver.

Excursion and Suspension: Mechanical Control for Infra-Bass

To achieve clean low-frequency extension and withstand high excursions, B&C specifies an Xmax of 15.0mm and a triple roll suspension. This type of suspension is favored in modern subwoofers for its ability to support cone movement while maintaining good centering and consistent behavior as levels increase. The double siliconed spider enhances mechanical stability, a key factor for precision and longevity in infra applications.

Waterproof Treated Cone: Consistency and Durability

The radial cone features a waterproof treatment front and back, an advantage for durability in demanding environments (transport, humidity variations, regular use). This protection also helps preserve mechanical characteristics over time, aiding in maintaining consistent performance throughout its service life.

Technical specifications

Rackable	No	Type	Speakers
Category	sound reinforcement accessory

Model	B&C 21SW152	Xmax	15.0mm
Impedance	4 Ohms	Suspension	triple roll
Power	4000W AES	Cone	radial with waterproof treatment front and back
Sensitivity	96dB 1W/1m	Spider	double siliconed
Frequency Response	30Hz - 1kHz	Total Diameter	547mm
Fs	32Hz	Height	261mm
Qts	0.36	Weight	18.5kg
Voice Coil	6.0" (153mm) copper wire	Recommended Enclosure	190 liters tuned to 33Hz
Magnet	neodymium