Quantum Audio QPW3000/8D4
8″ subwoofer · dual 4 Ω · 350 W RMS
| Source | dbdrive.net · manufacturer data |
|---|---|
| Checked against source | October 2026 |
| Thiele/Small parameters | not in the spec sheet: Xmax — typical value for the size used |
| Mounting dimensions | 3 of 4 — missing: magnet diameter; the designer will use an estimate |
Recommended box
For a sedan, one sub, 350 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) | Dry and tight · 0.56 |
|---|---|
| Fc | 58 Hz |
| F3 (−3 dB, no cabin gain) | 80 Hz |
| Example box (outside) | 10 1/4″ × 10 1/4″ × 8 1/2″ |
Ported
deeper, louder| Tuning (Fb) | 41 Hz |
|---|---|
| Port | slot 1 3/8 × 14 5/16″, 31 7/8″ long |
| Port velocity at 350 W | 58 ft/s |
| F3 (−3 dB, no cabin gain) | 36 Hz |
| Example box (outside) | 18 1/16″ × 15 3/4″ × 11 13/16″ |
Deeper: 0.57 ft³ (16 L) tuned to 42 Hz, 15″ × 15 3/4″ × 7 1/16″ 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 | 8″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | 350 W |
| Fs | 41.1 Hz |
| Qts | 0.39 |
| Qes | 0.44 |
| Qms | 3.8 |
| Vas | 0.28 ft³ |
| Re (one coil) | 4 Ω |
|---|---|
| Sd | 29.7 in² |
| Xmax | ≈ 0.39″ |
| Mms | 98 g calc. |
| BL | 15.2 T·m calc. |
| EBP | 93 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 83 dB calc. |
Mounting dimensions
| Cutout diameter | 7 3/16″ |
|---|---|
| Mounting depth | 4 9/16″ |
| Overall diameter | 8 7/16″ |
Cone area (Sd) calculated from Fs, Vas and Mms: 29.7 in².
“≈” 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 8″ models
- Quantum Audio QW3000/8D4 8″ · dual 4 Ω
- Quantum Audio QWX4000/8D4 8″ · dual 4 Ω
Similar 8″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Sundown Audio U-8 D4 0.32 ft³ sealed · 0.67 ft³ ported
- Sundown Audio SAv3-8 D4 0.35 ft³ sealed · 0.67 ft³ ported
- Sundown Audio HZ-8 D4 0.28 ft³ sealed · 0.49 ft³ ported
- Helix IQ W8-DVC2 (2x2 Ohm) 0.32 ft³ sealed · 0.57 ft³ ported
- Sundown Audio Ev5-8 D2 0.28 ft³ sealed · 0.49 ft³ ported
- Machete MF-08S D4 0.32 ft³ sealed · 0.53 ft³ ported
FAQ
What box does the Quantum Audio QPW3000/8D4 need?
Recommended net volume: 0.28 ft³ sealed, 0.88 ft³ ported tuned to 41 Hz — for one sub in a sedan at 350 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the Quantum Audio QPW3000/8D4 Thiele/Small specs?
Fs 41.1 Hz, Qts 0.39, Vas 0.28 ft³, Sd 29.7 in².
What is the Quantum Audio QPW3000/8D4 mounting depth?
Mounting depth is 4 9/16″, cutout diameter 7 3/16″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Quantum Audio QPW3000/8D4 handle and how do I wire it?
RMS power rating: 350 W. Dual 4 Ω voice coils: series gives 8 Ω, parallel gives 2 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.