21S subwoofer

21S-SUB subwoofer front horziontal21S-SUB subwoofer back21S-SUB subwoofer front upright
21S-SUB subwoofer front upright
21S-SUB subwoofer front horziontal
21S-SUB subwoofer back

21S subwoofer

Subwoofers

Installation specific high performance subwoofer with compact footprint

  • Components 21"
  • Dispersion Omni directional
  • SPLmax 135 dB
  • Weight 54 kg / 119 lb

Article number Z1613

Where to buy

Product description

The 21S-SUB is a high performance subwoofer for use with the xS-Series and xA-Series loudspeakers and is intended for a wide range of permanently installed applications. The cabinet houses a single long excursion 21" driver in a bass-reflex design. The large, specially shaped reflex port enables the 21S-SUB to achieve high Sound Pressure Levels from a cabinet with a small footprint. 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 individually 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 (WR) option provides an IP55 rating that enables the operation of loudspeakers in changing ambient conditions, and features a fixed cable.

Amplifiers

The following current d&b amplifiers can be used to drive the loudspeaker:

Mobile

Installation


For further information on which heritage d&b amplifiers can be used to drive the loudspeaker, please refer to the current release notes on the amplifier firmware.
System data
Frequency response (-5 dB standard)
35 - 105 Hz
Frequency response (–5 dB INFRA mode)
33 - 85 Hz
Max. sound pressure1
with D25/25D
with D40/D80/D90/40D

135 dB
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

1 1 m, free field, SPL max peak, test signal: pink noise with crest factor 4, one speaker driven

Title
Category
File type
Size
Language
Release
 
2D DWG CAD package 1.4
2D CAD drawings
ZIP
388 MB
25.02.2025
2D DWG CAD package Release notes 1.4
2D CAD drawings
PDF
626 KB
English
25.02.2025
3D DWG CAD package release notes 1.5
3D CAD drawings
PDF
346 KB
English
07.05.2026
3D DWG CAD package 1.5
3D CAD drawings
ZIP
252 MB
07.05.2026
The xS-Series brochure
Brochures
PDF
3.84 MB
English
02.05.2023
24S/21S-SUB Introductory brochure
Brochures
PDF
2.24 MB
English
17.07.2019
21S-SUB Datasheet 1.1
Datasheets
PDF
297 KB
English
05.03.2023
EU Declaration of Conformity (CE) Subwoofer
Declarations of conformity
PDF
251 KB
English
04.11.2023
Architectural specifications 21S-SUB
Loudspeakers
TXT
1.55 KB
English
30.05.2020
Architectural specifications xS-Series
Loudspeakers
ZIP
13.97 KB
English
20.01.2017
21S-SUB Manual 1.3
Manuals
PDF
1.84 MB
English
04.12.2018
d&b Revit Families - xS-Series - Release notes 1.3
Revit files/BIM
PDF
591 KB
30.04.2026
d&b Revit Families - xS-Series 1.3
Revit files/BIM
ZIP
43 MB
30.04.2026
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Mobile application or fixed installation? Indoors or outdoors? Large or small? d&b provides tailored-made solutions for each and every requirement. What is more, the dedicated simulation software optimizes the planning of the system installation.
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