Media
Auto-advancing
Size
21"
Impedance
8Ω
RMS Power
3400W
Sensitivity
99dB
EBP
121
Vented alignment
Vd
2673cm³
Frequency response
Manufacturer-provided response plots and related charts.
T/S Parameters
Valid
Fs34Hz
Qts0.27
Qes0.28
Qms10.2
Vas204.0L
Re5.1Ω
Le4.90mH
BL39.3Tm
Sd1620cm²
Mms404g
Xmax16.5mm
SPL99dB
Power3400W
Power Nominal1700W
Impedance8Ω
Min Impedance6.6Ω
F Low35Hz
F High500Hz
Voice Coil116mm
Flux Density0.80T
Pricing & availability
Price movement
Other offers
2 vendorsbluearan
Updated 17 May 2026· 8Ω
Source: inc VAT · 20%
£497.00
inc VAT
jpleisure
Updated 17 May 2026· 8Ω
Source: ex VAT · 20%
£502.90
inc VAT
Best current price
Updated 17 May 2026
bluearan
£497.00
Avg £498.97£1.97 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
Bl39.3 Tm
Fs34 Hz
Le4.9 mH
Re5.1 Ω
Sd1620 cm² (251.1 in²)
Ebp121 Hz
Mms404 g
Qes0.28
Qms10.2
Qts0.27
Vas204 dm³ (7.2 ft³)
η02.7 %
ConeRCK21DS1158
Xmax16.5 mm
Xvar13.5 mm
SpiderDouble Silicone
Cone ShapeRadial
Pole DesignT-Pole
Winding Depth40 mm (1.57 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 Enclosure170 dm³ (6 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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