B&C Speakers 21DS115

A 21-inch B&C built for modern sound reinforcement and large subwoofer enclosures

The B&C 21DS115 fits within the logic of very large diameter drivers intended to produce massive energy in the low spectrum, where an 18-inch sometimes reaches its limits in ambitious setups. With its 21-inch (53 cm) format and infra-bass oriented design, it clearly targets high sound pressure level (SPL) systems: subwoofer enclosures for tours, large capacity fixed installations, or demanding DIY projects seeking "live" bass and significant dynamic reserve.

Its recommended enclosure volume already provides a very concrete direction: 130 liters with a tuning at 40 Hz. This type of recommendation facilitates implementation in a high-performance bass reflex enclosure, consistent with stage/sound reinforcement use where level, impact, and solid low-end response are sought.

Who is this infra-bass loudspeaker for?

This model is aimed at integrators, rental companies, enclosure manufacturers, and speaker design enthusiasts who need a transducer capable of sustaining high levels and bass-rich programs. In practice, it will find its place in a subwoofer enclosure dedicated to contemporary music (electro, hip-hop, rock), clubs and venues, as well as event sound reinforcement systems where infra-bass must remain clean, stable, and physical.

Thanks to its sensitivity of 99 dB (1 W/1 m) and excursion capability (Xmax 15 mm), it is relevant when the goal is to achieve high acoustic pressure while maintaining mechanical durability suitable for heavy use. It is also a good candidate for multi-subwoofer systems where radiating surfaces are combined to extend coverage and level in the bass.

Design and key points for bass performance

The 21DS115 combines technical choices focused on efficiency, reliability, and mechanical durability. The neodymium magnet contributes to an efficient motor while keeping a coherent weight for a 21-inch driver, which can make a difference in logistics (handling, stacking, transport) when deploying multiple subwoofers.

Large format voice coil and heat dissipation

The 4.5-inch (115 mm) voice coil uses a copper-clad aluminum wire. This architecture is common in high-power loudspeakers as it aims for a good compromise between moving mass and the ability to handle sustained high levels. Result: a loudspeaker designed to maintain control in the low end while accepting significant power over time, in real sound reinforcement contexts.

Suspension, centering, and excursion durability

The triple roll suspension and double siliconed spider are key elements for excursion stability. On a 21-inch driver intended for infra-bass, mechanical durability and movement consistency are essential: they contribute to bass clarity, limit unwanted behaviors, and secure operation when the system is driven at high levels.

Treated radial cone: reliability and consistency

The radial cone benefits from a waterproof treatment front and back. For professional or semi-pro use, this protection helps maintain consistent performance against humidity and variable conditions (transport, storage, stages, installations). This is an appreciated point for the durability of a subwoofer enclosure regularly used on the road.

Technical specifications

Rackable	No	Type	Speakers
Category	sound reinforcement accessory

Infra-bass loudspeaker	21 inches (53 cm)	Qts	0.23
Power	3400 W AES	Xmax	15.0 mm
Nominal impedance	8 ohms	Suspension	triple roll
Sensitivity	99 dB (1 W/1 m)	Cone	radial with waterproof treatment front/back
Frequency response	30 Hz - 1 kHz	Spider	double siliconed
Magnet	neodymium	Total diameter	547 mm
Voice coil	4.5 inches (115 mm)	Height	255 mm
Wire type	copper-clad aluminum	Weight	17.1 kg
Fs	30 Hz	Recommended volume	130 liters with tuning at 40 Hz