Quantum Audio QWX4000/15D4
15″ subwoofer · dual 4 Ω
| Source | web.archive.org · manufacturer data |
|---|---|
| Checked against source | October 2026 |
| Thiele/Small parameters | complete |
| Mounting dimensions | 0 of 4 — missing: cutout, mounting depth, frame outer diameter, magnet diameter; the designer will use an estimate |
Recommended box
For a sedan, one sub, 300 W. It’s the same math as the designer’s step-by-step mode, where you can fit the box to your space, vehicle and amp and get plans, a cut sheet and DXF.
Sealed
smaller, tighter| Bass character (Qtc) | Boomy, with a bump · 0.98 |
|---|---|
| Fc | 51 Hz |
| F3 (−3 dB, no cabin gain) | 42 Hz |
| Example box (outside) | 31 1/2″ × 18 1/8″ × 11 3/4″ |
Ported
deeper, louder| Tuning (Fb) | 34 Hz |
|---|---|
| Port | slot 1 9/16 × 16 11/16″, 26 1/2″ long |
| Port velocity at 300 W | 37 ft/s |
| F3 (−3 dB, no cabin gain) | 37 Hz |
| Example box (outside) | 31 1/2″ × 18 1/8″ × 10 3/4″ |
Deeper: 4.84 ft³ (137 L) tuned to 35 Hz, 31 1/2″ × 18 1/8″ × 19 1/2″ outside — a bigger box with flatter deep bass. Open in the calculator
Projects with this subwoofer
Boxes that users designed and published: plans, cut sheet and response graph.
Thiele/Small parameters
| Size | 15″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | — |
| Fs | 37.9 Hz |
| Qts | 0.74 |
| Qes | 0.873 |
| Qms | 4.65 |
| Vas | 2.21 ft³ |
| Re (one coil) | 3.4 Ω |
|---|---|
| Sd | 124.7 in² |
| Xmax | 0.51″ |
| Vd | 63.8 in³ calc. |
| Mms | 258 g calc. |
| BL | 15.5 T·m calc. |
| EBP | 43 — suits sealed calc. |
| Sensitivity, 1 W / 1 m | 87.9 dB calc. |
Mounting dimensions
| Cutout diameter | ≈ 14″ |
|---|---|
| Mounting depth | ≈ 7 1/16″ |
“≈” means the value isn’t in the spec sheet and a typical value for the size is used; “calc.” means it’s calculated from the published parameters. Check the manufacturer’s spec sheet before you build.
Data sources
Other Quantum Audio 15″ models
- Quantum Audio Q2000/15D 15″ · dual 4 Ω
- Quantum Audio Q2500/15D 15″ · dual 4 Ω
- Quantum Audio Q3000/15D 15″ · dual 4 Ω
- Quantum Audio QW3000/15D4 15″ · dual 4 Ω
- Quantum Audio QW5000/15D4 15″ · dual 4 Ω
Similar 15″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Timpano TPT-T1500-15 D4 2.83 ft³ sealed · 1.98 ft³ ported
- Massive Audio GTX154 2.86 ft³ sealed · 2.01 ft³ ported
- Sundown Audio SA Rev.3-15 D4 2.79 ft³ sealed · 1.94 ft³ ported
- Machete MF-15 D2 2.83 ft³ sealed · 2.01 ft³ ported
- Memphis Car Audio MJP1522 (MOJO Pro 15" DVC 2ohm) 2.93 ft³ sealed · 2.05 ft³ ported
- Soundstream SPLX-152 ('07-'08) 3.04 ft³ sealed · 2.12 ft³ ported
FAQ
What box does the Quantum Audio QWX4000/15D4 need?
Recommended net volume: 2.83 ft³ sealed, 1.98 ft³ ported tuned to 34 Hz — for one sub in a sedan at 300 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the Quantum Audio QWX4000/15D4 Thiele/Small specs?
Fs 37.9 Hz, Qts 0.74, Vas 2.21 ft³, Xmax 0.51″, Sd 124.7 in².