Diamond M3151
15″ subwoofer · 4 Ω · 250 W RMS
| Source | web.archive.org · manufacturer data |
|---|---|
| Checked against source | October 2026 |
| Thiele/Small parameters | not in the spec sheet: Re — 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, 250 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) | Tight and punchy · 0.80 |
|---|---|
| Fc | 46 Hz |
| F3 (−3 dB, no cabin gain) | 44 Hz |
| Example box (outside) | 31 1/2″ × 17 11/16″ × 11 3/8″ |
Ported
deeper, louder| Tuning (Fb) | 30 Hz |
|---|---|
| Port | slot 1 9/16 × 16 5/16″, 15 13/16″ long |
| Port velocity at 250 W | 51 ft/s |
| F3 (−3 dB, no cabin gain) | 31 Hz |
| Example box (outside) | 31 1/2″ × 17 11/16″ × 16 9/16″ |
Deeper: 4.98 ft³ (141 L) tuned to 30 Hz, 31 1/2″ × 17 11/16″ × 20 3/8″ 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 | 4 Ω |
| RMS power | 250 W |
| Fs | 24 Hz |
| Qts | 0.42 |
| Qes | 0.45 |
| Qms | 6.5 |
| Vas | 6.96 ft³ |
| Re | ≈ 3.4 Ω |
|---|---|
| Sd | 129 in² |
| Xmax | 0.30″ |
| Vd | 38.1 in³ calc. |
| Mms | 219 g calc. |
| BL | 15.8 T·m calc. |
| EBP | 53 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 89.8 dB calc. |
Mounting dimensions
| Cutout diameter | 13 3/4″ |
|---|---|
| Mounting depth | 6 7/16″ |
| Overall diameter | 15 1/4″ |
“≈” 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 Diamond 15″ models
- Diamond CM315D2 15″ · dual 2 Ω
- Diamond CM315D4 15″ · dual 4 Ω
- Diamond D315D2 15″ · dual 2 Ω
- Diamond D315D4 15″ · dual 4 Ω
- Diamond D615D2 15″ · dual 2 Ω
- Diamond D615D4 15″ · dual 4 Ω
- Diamond D915D2 15″ · dual 2 Ω
- Diamond D915D4 15″ · dual 4 Ω
- Diamond H152 15″ · dual 2 Ω
- Diamond H154 15″ · dual 4 Ω
- Diamond HXP152 15″ · dual 2 Ω
- Diamond HXP154 15″ · dual 4 Ω
Similar 15″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- RE Audio SRX15 D4 2.58 ft³ sealed · 3.71 ft³ ported
- Rockford Fosgate Punch HX2 RFD1215 (2000) 2.83 ft³ sealed · 3.67 ft³ ported
- Polk Audio MM2154 2.86 ft³ sealed · 3.74 ft³ ported
- Lanzar HRWDC15 2.12 ft³ sealed · 3.67 ft³ ported
- PowerBass M-1504 2.75 ft³ sealed · 3.57 ft³ ported
- Kicker Comp 15" 4-Ohm SVC (43C154) 2.75 ft³ sealed · 3.67 ft³ ported
FAQ
What box does the Diamond M3151 need?
Recommended net volume: 2.65 ft³ sealed, 3.81 ft³ ported tuned to 30 Hz — for one sub in a sedan at 250 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the Diamond M3151 Thiele/Small specs?
Fs 24 Hz, Qts 0.42, Vas 6.96 ft³, Xmax 0.30″, Sd 129 in².
What is the Diamond M3151 mounting depth?
Mounting depth is 6 7/16″, cutout diameter 13 3/4″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Diamond M3151 handle and how do I wire it?
RMS power rating: 250 W. Wiring for several subs and amp power — in the wiring calculator.