Diamond D315D2
15″ subwoofer · dual 2 Ω · 400 W RMS
| Source | web.archive.org · manufacturer data |
|---|---|
| Checked against source | October 2026 |
| Thiele/Small parameters | complete |
| Mounting dimensions | 3 of 4 — missing: magnet diameter; the designer will use an estimate |
Recommended box
For a sedan, one sub, 400 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 · 0.85 |
|---|---|
| Fc | 44 Hz |
| F3 (−3 dB, no cabin gain) | 40 Hz |
| Example box (outside) | 31 1/2″ × 17 5/16″ × 13 1/8″ |
Ported
deeper, louder| Tuning (Fb) | 30 Hz |
|---|---|
| Port | slot 1 9/16 × 15 7/8″, 14 1/2″ long |
| Port velocity at 400 W | 65 ft/s |
| F3 (−3 dB, no cabin gain) | 30 Hz |
| Example box (outside) | 31 1/2″ × 17 5/16″ × 17 1/2″ |
Deeper: 5.19 ft³ (147 L) tuned to 31 Hz, 31 1/2″ × 17 5/16″ × 22 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 | 15″ |
|---|---|
| Voice coils | dual 2 Ω |
| RMS power | 400 W |
| Fs | 25 Hz |
| Qts | 0.49 |
| Qes | 0.53 |
| Qms | 5.77 |
| Vas | 6.41 ft³ |
| Re (one coil) | 1.7 Ω |
|---|---|
| Sd | 134.2 in² |
| Xmax | 0.47″ |
| Vd | 62.9 in³ calc. |
| Mms | 237 g calc. |
| BL | 10.9 T·m calc. |
| EBP | 47 — suits sealed calc. |
| Sensitivity, 1 W / 1 m | 89.3 dB calc. |
Mounting dimensions
| Cutout diameter | 13 7/16″ |
|---|---|
| Mounting depth | 7 11/16″ |
| Overall diameter | 15 5/16″ |
“≈” 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 Diamond 15″ models
- Diamond CM315D2 15″ · dual 2 Ω
- Diamond CM315D4 15″ · dual 4 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
- Diamond M3151 15″ · 4 Ω
Similar 15″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- JBL GTO1502D 3.04 ft³ sealed · 3.92 ft³ ported
- Polk Audio MM2154 2.86 ft³ sealed · 3.74 ft³ ported
- JBL GTO1514D 2.93 ft³ sealed · 3.81 ft³ ported
- Polk Audio MM2154 DVC 2.86 ft³ sealed · 3.74 ft³ ported
- Rockford Fosgate Punch HX2 RFD1215 (2000) 2.83 ft³ sealed · 3.67 ft³ ported
- Gladen M 15 (SVC 4 ohm) 2.93 ft³ sealed · 3.81 ft³ ported
FAQ
What box does the Diamond D315D2 need?
Recommended net volume: 3.07 ft³ sealed, 3.99 ft³ ported tuned to 30 Hz — for one sub in a sedan at 400 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the Diamond D315D2 Thiele/Small specs?
Fs 25 Hz, Qts 0.49, Vas 6.41 ft³, Xmax 0.47″, Sd 134.2 in².
What is the Diamond D315D2 mounting depth?
Mounting depth is 7 11/16″, cutout diameter 13 7/16″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Diamond D315D2 handle and how do I wire it?
RMS power rating: 400 W. Dual 2 Ω voice coils: series gives 4 Ω, parallel gives 1 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.