SoundQubed HDX4 Series Subwoofer 18" D1
SoundQubed HDX4 Series Subwoofer 18" D1
SoundQubed HDX4 Series Subwoofer 18" D1

SoundQubed HDX4 Series Subwoofer 18" D1

Regular price$799.95

  • Free shipping*

HDX subwoofers build upon the design of the HDC line in response to recent shifts in source material and the mainstream frequency tuning of our customers’ vehicles. Our team scrutinized all aspects of the HDC subs to improve performance at lower frequencies. The resulting HDX dual voice coil competition subwoofer line is more efficient, plays lower, and sounds better setting a new bar for performance and value.


The new cast basket accommodates larger diameter spiders, providing more room for cone and spider travel. Heat dissipates more quickly with greater movement and a more open airflow path.

New spiders with more, higher rolls take advantage of the increased suspension travel. This extra material in the spiders increases the freedom of movement, lowering the Fs, while maintaining durability over time.

The subwoofer’s surround profile is higher, reducing material stress while increasing excursion. Cone area and moving mass remain virtually the same, as opposed to inner-tube surrounds popping up here and there.


A fiberglass-reinforced pulp cone meets the strength demands of the increased excursion. A non-press cone formation process increases the cross-section area of the cone walls for more rigidity without adding extra mass.

The voice coils feature high-quality, American-made wire and adhesives increasing the thermal working range of the coil. Additionally, thicker, black-anodized aluminum formers increase thermal transfer from the coil wire.

The HDX line makes it easier to tune low-frequency pressure into a system without sacrificing impact. HDX subs allow you to explore design choices with high efficiency, making the most of amplifier power and electrical resources.

  • 2000 Watts RMS, 6000 Watts Peak (Burp Only)
  • 4″ Voice Coil
  • Dual 1 Ohm Impedance
  • Cast Frames
Model HDX412 HDX415 HDX418
RMS Power 2000 W  2000 W  2000 W
Peak Power 6000 W  6000 W  6000 W
Magnet Weight 403 oz  403 oz  403 oz
Coil Diameter 4"  4"  4"
Woofer Size 12" 15" 18"
F(s) 30.95 Hz 29.61 Hz 22.8 Hz
Impedance D1 D1 D1
Z(max) 21.2 Ohms 22.43 Ohms 19.3 Ohms
Q(ms) 3.664 4.047 4.568
Q(es) 0.344 0.3658 0.4852
Q(ts) 0.3145 0.3355 0.4386
V(as) 24.93 Liters 55.04 Liters 163.3 Liters
L(e) 0.7672 0.8143 2.477
n(0) 0.205% 0.372% 0.384%
M(ms) 422 grams 500.3 grams 616.8 grams
C(ms) 0.063 0.058 0.078
Sensitivity (1W/1m) 85.22 dB 87.81 dB 87.95dB
BL 20.84 21.75 18.4
Xmax 21 21 31
Sd 260.4 mm 323.9 mm 393.7 mm
Displacement 0.2³ 0.22³ 0.32³
Mounting Depth 8 5/8" 9 3/8" 11 5/8"
Circle Cutout 11 3/8" 13 7/8" 16 9/16"
Ported Enclosure (Cu Ft): 1.75-2.75 FT³ 3-6 FT³ 5-7 FT³

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