Do-it-yourselfers, here’s your chance to create your personal sub that perfectly fits into your car!
From the technical point of view the two drivers K 10W and K12W are absolutely identical with the subwoofers that are installed in the K series enclosure subs.

Just have a look at the Thiele/Small parameters and you will easily notice that those are designed for compact vented cabinets yet leaving plenty of “headroom” for designing your own preferred sound characteristic. If you prefer to play it safe, just choose the same net volume and port tuning frequency like our enclosure subs K 10E and K 12E for outstanding bass performance.

So what are you waiting for? Start your “tailor-made subwoofer project” right now!



  • Extremely stiff, hand-scooped paper cone
  • Double ventilated voice coil for minimum compression effects and high power handling
  • Long-excursion rubber surround for highest mechanical rating
  • Very long linear excursion
  • 2 x 2 Ohms dual voice coil for flexible system configuration
  • Solid push terminals
  • Powerful magnet system for compact vented enclosures
  • Rugged magnet cover with HELIX lettering for perfect magnet protection
  • Grille and gasket included in delivery
Power RMS / max. P300 / 600 Watt
Impedance Z2 x 2 Ω
DC resistance Re2 x 1.6 Ω
Resonance frequency Fs32 Hz
Mechanical Q factor Qms3.70
Electrical Q factor Qes0.46
Total Q factorQts0.41
ComplianceCms179 μm/N
Equivalent air volumeVas66 L
Force factor B*I13.7 Tm
Efficiency 1 W / 1 mSPL90.0 dB
Cone area Sd515 cm²
Moving mass Mms134 g
Cone material Hand-scooped paper cone
Mechanical resistance Rms7.33 kg/s
Voice coil diameterø50.8 mm
Voice coil winding height 24 mm
Max. linear excursion Xmax+/- 8.0 mm
Outer diameterø316 mm / 12.44″
Installation diameterø286 mm / 11.26
Installation depth 144 mm / 5.67″
Recommended enclosure volumes 
Sealed box 
Net volume 18 L
Lower limiting frequency (-3dB) 49 Hz
Vented box 
Net volume 30 L
Port diameterø100 mm / 3.94″
Port area 78 cm²
Port length 28 cm / 9.84″
Port tuning frequencyFb39 Hz
Lower limiting frequency (-3dB) 39 Hz
Delivery contents

1 x Subwoofer HELIX K 12W
1x Grille
1 x Gasket
1 x Data sheet