Media
Auto-advancing
Size
21"
Impedance
4Ω
RMS Power
3400W
Sensitivity
100dB
EBP
145
Vented alignment
Vd
2430cm³
Frequency response
Manufacturer-provided response plots and related charts.
T/S Parameters
Valid
Fs32Hz
Qts0.21
Qes0.22
Qms9.8
Vas219.0L
Re2.1Ω
Le2.30mH
BL28.6Tm
Sd1620cm²
Mms409g
Xmax15.0mm
SPL100dB
Power3400W
Power Nominal1700W
Impedance4Ω
Min Impedance3.1Ω
F Low30Hz
F High500Hz
Voice Coil116mm
Flux Density0.80T
Pricing & availability
Price movement
Other offers
1 vendorjpleisure
Updated 17 May 2026· 4Ω
Source: ex VAT · 20%
£500.70
inc VAT
Best current price
Updated 17 May 2026
bluearan
£497.00
Avg £498.85£1.85 below avg (-0.4%)
inc VAT
Dimensions & Physical
Weight14.7kg
Diameter547.0mm
Overall Depth255.0mm
Cutout Diameter508.0mm
Bolt Circle Diameter527.0mm
Additional Manufacturer Specs
Bl28.6 Tm
Fs32 Hz
Le2.3 mH
Re2.1 Ω
Sd1620 cm² (251.1 in²)
Ebp145 Hz
Mms409 g
Qes0.22
Qms9.8
Qts0.21
Vas219 dm³ (7.73 ft³)
η03.3 %
ConeRCK21DS1154
Xmax15 mm
Xvar11.5 mm
SpiderDouble Silicone
Cone ShapeRadial
Pole DesignT-Pole
Winding Depth36 mm (1.42 in)
Surround ShapeTriple Roll
Former MaterialGlass Fibre
Magnet MaterialNeodymium Inside Slug
Nominal Diameter530 mm (21 in)
Winding MaterialAluminium
Magnetic Gap Depth14 mm (0.55 in)
Recommended Tuning40 Hz
Bolt Circle Diameter527 mm (20.7 in)
Recommended Enclosure130 dm³ (4.59 ft³)
Woofer Cone TreatmentTWP Waterproof Both Sides
Baffle Cutout Diameter508 mm (20 in)
Flange And Gasket Thickness13 mm (0.51 in)
Air Volume Occupied By Driver15 dm³ (0.53 ft³)
Similar Drivers
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Reference
B&C
21DS115
21"
Best current price
£497.00
Compare on
Only active params are shown here. Size stays fixed automatically.
5 active T/S params, plus size.
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