PowerBass 3XL-121D
12″ subwoofer · dual 1 Ω · 850 W RMS
| Source | web.archive.org · manufacturer data |
|---|---|
| Checked against source | October 2026 |
| Thiele/Small parameters | complete |
| Mounting dimensions | 1 of 4 — missing: cutout, frame outer diameter, magnet diameter; the designer will use an estimate |
Recommended box
For a sedan, one sub, 850 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) | Flat and accurate · 0.68 |
|---|---|
| Fc | 54 Hz |
| F3 (−3 dB, no cabin gain) | 59 Hz |
| Example box (outside) | 14 3/16″ × 14 3/16″ × 10 1/16″ |
Ported
deeper, louder| Tuning (Fb) | 34 Hz |
|---|---|
| Port | slot 1 9/16 × 14 5/16″, 37 1/8″ long |
| Port velocity at 850 W | 75 ft/s |
| F3 (−3 dB, no cabin gain) | 33 Hz |
| Example box (outside) | 20 7/16″ × 15 3/4″ × 14 3/8″ |
Deeper: 1.52 ft³ (43 L) tuned to 33 Hz, 31 1/2″ × 15 3/4″ × 12 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 | 12″ |
|---|---|
| Voice coils | dual 1 Ω |
| RMS power | 850 W |
| Fs | 32.3 Hz |
| Qts | 0.41 |
| Qes | 0.446 |
| Qms | 4.57 |
| Vas | 1.28 ft³ |
| Re (one coil) | 1.03 Ω |
|---|---|
| Sd | 79.2 in² |
| Xmax | 0.53″ |
| Vd | 42.1 in³ calc. |
| Mms | 248 g calc. |
| BL | 10.8 T·m calc. |
| EBP | 72 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 86.4 dB calc. |
Mounting dimensions
| Cutout diameter | ≈ 11 1/8″ |
|---|---|
| Mounting depth | 7 1/8″ |
“≈” 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 PowerBass 12″ models
- PowerBass 3XL-1201D 12″ · dual 1 Ω
- PowerBass 3XL-1210D 12″ · dual 1 Ω
- PowerBass L-1204D 12″ · dual 4 Ω
- PowerBass S-12T 12″ · 4 Ω
- PowerBass S-1204D 12″ · dual 4 Ω
Similar 12″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Soundstream SPLX-122HX 0.71 ft³ sealed · 1.27 ft³ ported
- American Bass ELITE-1222 0.71 ft³ sealed · 1.27 ft³ ported
- Kicker CompVX 12" 2-Ohm DVC (50CVX122) 0.74 ft³ sealed · 2.40 ft³ ported
- SSA ICON 12 D4 0.67 ft³ sealed · 1.20 ft³ ported
- Resilient Sounds RS 12 V2 D4 0.74 ft³ sealed · 1.31 ft³ ported
- Sundown Audio Ev4-12 D2 0.71 ft³ sealed · 1.77 ft³ ported
FAQ
What box does the PowerBass 3XL-121D need?
Recommended net volume: 0.71 ft³ sealed, 1.27 ft³ ported tuned to 34 Hz — for one sub in a sedan at 850 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the PowerBass 3XL-121D Thiele/Small specs?
Fs 32.3 Hz, Qts 0.41, Vas 1.28 ft³, Xmax 0.53″, Sd 79.2 in².
What is the PowerBass 3XL-121D mounting depth?
Mounting depth is 7 1/8″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the PowerBass 3XL-121D handle and how do I wire it?
RMS power rating: 850 W. Dual 1 Ω voice coils: series gives 2 Ω, parallel gives 0.5 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.