The d&b audiotechnik 21S-SUB is a space-saving, flyable subwoofer for fixed installation with a 21″ neodymium driver in an impact resistant, bass-reflex cabinet with rubber feet for stacking protection, and side-panel bracket threads for flown installation
The 21S-SUB houses a 21″ neodymium driver housed in a space-conscious cabinet, built for fixed installation in a variety of applications. Designed for use with d&b audiotechnik xS-Series and xA-Series loudspeakers, the 21S-SUB is a high-performance, 2,600W (peak) design with a maximum SPL of 135dB. The 21S-SUB cabinet houses a long-excursion, 21″ neodymium driver in a bass-reflex design. The large, specially shaped reflex port enables the 21S-SUB to achieve high sound pressure levels (SPL) with minimal power compression and breathing effects. When operated in INFRA mode, the 21S-SUB can be used to complement other d&b subwoofers by extending the frequency response of the system down to 33Hz. The 21S-SUB can be ground stacked or flown in either orientation. It can be flown inpidually or in a cluster of two cabinets.
The enclosure is constructed from marine plywood with an impact resistant black paint finish. The front of the loudspeaker cabinet is protected by a rigid metal grill backed by an acoustically transparent foam. The top, bottom and rear panels each incorporate a pair of M10 threaded inserts for attaching d&b rigging hardware. The Weather Resistant option enables the operation of loudspeakers in changing ambient conditions, and features a fixed cable. The 21S-SUB can also be supplied in any RAL color. This Special Color option can be provided for rigging accessories. The loudspeaker cabinets and most accessories are also available with the Special Color (SC) option that can be executed in all RAL* colors, while the Weather Resistant (WR) option provides an IP55* rating, and enables operation of loudspeakers in changing ambient conditions.
*RAL is a color-matching system that defines standard colors for varnish, powder coating, and plastics. It’s the most popular Central European color standard used today.
**The IP Code or International Protection Rating, sometimes also interpreted as Ingress Protection Rating. IP55: Protected from limited dust ingress. Protected from low-pressure water jets from any direction.
21S-SUB rigging components
The top, bottom and side panels of the cabinet are each equipped with a pair of M10 threaded inserts to connect to different rigging accessories such as:
For use as a base, the 21S-SUB is equipped with four rubber feet to prevent cabinet movement and protect the bottom panel against scratching. The cabinet is Ball-Impact Resistant according to DIN 18032-3.
Compatible amplifiers
The d&b amplifiers are designed specifically to power d&b loudspeakers, forming the heart of the d&b System. They incorporate digital signal processing for comprehensive loudspeaker management, switchable filter functions, remote capabilities, and user-definable controls to fulfill the exact needs of each application.
d&b LoadMatch
Starting with the D80 amplifier platform, the LoadMatch function enables the amplifier to electrically compensate for the properties of the loudspeaker cable used without the need for an additional sense wire. For applicable loudspeakers, LoadMatch is therefore independent of the connector type used.
The d&b 30D amplifier is recommended to drive the 21S-SUB. The d&b D20 and D80 can also be used.
21S-SUB applications:
System data
Frequency response (-5 dB standard): 35 - 105 Hz
Frequency response (–5 dB INFRA mode): 33 - 85 Hz
Max. sound pressure1
with D20/30D: 134 dB
with D40/D80/40D: 135 dB
Cabinets per amplifier channel: 1
Loudspeaker data
Configuration: Installation specific high performance subwoofer with compact footprint
Nominal impedance: 4 Ω
Power handling capacity (RMS/peak 10 ms): 650/2600 W
Components: 21" driver with neodymium magnet
Connections: 1 x NL4/1 x screw terminal block
Dimensions / weight
Dimensions (H x W x D): 1100 x 580 x 526 mm/43.3 x 22.8 x 20.7"
Weight: 54 kg/119 lb