Sundown Audio XV4 18-Inch 3000W Subwoofer – Dual 1 ohm X Series
Best box: 161.6 L bass reflex tuned to 22.7 Hz · F3 20.8 Hz
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Comparable 18.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Sundown Audio XV4 18-Inch 3000W Subwoofer – Dual 1 ohm X Series does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- The textbook alignment (140.5 L at 18.9 Hz) would need a 173.3 cm port; the recommendation is retuned to 161.6 L at 22.7 Hz so the port can be built.
- Port length (98.8 cm) exceeds a straight internal run; use an elbow bend, slotted vent or 3D folded duct to fit the enclosure.
- Large enclosure volume (161.6 L) requires extensive internal matrix bracing to prevent panel resonance.
Recommended Bass Reflex (Vented)
PORT NEEDS ELBOW / 3D| Net Box Volume (Vb) | 161.6 Liters |
| Tuning Frequency (Fb) | 22.7 Hz |
| F3 (-3 dB Cutoff) | 20.8 Hz |
| F6 / F10 Extension | 18.7 Hz / 16.8 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | 98.8 cm |
| First Pipe Resonance | 174.0 Hz |
| Estimated MOL @ F3 | 111.3 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 131.2 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 33.4 Hz |
| F3 (-3 dB Cutoff) | 34.1 Hz |
| F6 / F10 Extension | 25.7 Hz / 19.4 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 25.9 Hz |
| Total Q (Qts) | 0.54 |
| Electrical Q (Qes) | 0.621 |
| Mechanical Q (Qms) | 4.13 |
| Equivalent Volume (Vas) | 93.7 Liters |
| Diaphragm Area (Sd) | 1210.0 cm² |
| DC Resistance (Re) | 30.0 Ω |
| Efficiency Bandwidth Product (EBP) | 41.6 |
| Linear Excursion (Xmax) | 30.0 mm |
| Thermal Power (Pe) | 500.0 W |
| Nominal Diameter | 18.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Sundown Audio XV4 18-Inch 3000W Subwoofer – Dual 1 ohm X Series?
Load Forge's calculated alignment puts Sundown Audio XV4 18-Inch 3000W Subwoofer – Dual 1 ohm X Series in a 161.6 liter vented enclosure tuned to 22.7 Hz, reaching an F3 cutoff of approximately 20.8 Hz.
Can Sundown Audio XV4 18-Inch 3000W Subwoofer – Dual 1 ohm X Series be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 131.2 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 34.1 Hz.
What port dimensions should be used for Sundown Audio XV4 18-Inch 3000W Subwoofer – Dual 1 ohm X Series to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 20.0 cm with a length of 98.8 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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