Diamond CM315D2
15″ subwoofer · dual 2 Ω
| 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, 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) | Tight and punchy · 0.92 |
|---|---|
| Fc | 43 Hz |
| F3 (−3 dB, no cabin gain) | 37 Hz |
| Example box (outside) | 31 1/2″ × 17 11/16″ × 11 7/8″ |
Ported
deeper, louder| Tuning (Fb) | 33 Hz |
|---|---|
| Port | slot 1 9/16 × 16 5/16″, 21 11/16″ long |
| Port velocity at 300 W | 44 ft/s |
| F3 (−3 dB, no cabin gain) | 32 Hz |
| Example box (outside) | 31 1/2″ × 17 11/16″ × 12 3/16″ |
Deeper: 4.73 ft³ (134 L) tuned to 31 Hz, 31 1/2″ × 17 11/16″ × 19 11/16″ 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 | — |
| Fs | 30 Hz |
| Qts | 0.64 |
| Qes | 0.69 |
| Qms | 8 |
| Vas | 3.06 ft³ |
| Re (one coil) | 1.65 Ω |
|---|---|
| Sd | 122.5 in² |
| Xmax | 0.43″ |
| Vd | 53 in³ calc. |
| Mms | 287 g calc. |
| BL | 11.4 T·m calc. |
| EBP | 43 — suits sealed calc. |
| Sensitivity, 1 W / 1 m | 87.3 dB calc. |
Mounting dimensions
| Cutout diameter | 13 15/16″ |
|---|---|
| Mounting depth | 7 3/8″ |
| Overall diameter | 15 3/8″ |
“≈” 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
- web.archive.org/web/20070830083842/http://www.diamondaudio.com/PDF/archive/CM3/C
- web.archive.org/web/20050405075111/http://www.diamondaudio.com:80/products/pdfs/
Other Diamond 15″ models
- 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
- 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.
- Audiobahn DUB500 2.72 ft³ sealed · 2.44 ft³ ported
- DC Audio Level 3 M3 15 D1 2.90 ft³ sealed · 2.40 ft³ ported
- DC Audio Level 3 M3 15 D2 2.90 ft³ sealed · 2.40 ft³ ported
- DC Audio Level 3 M3 15 D4 2.90 ft³ sealed · 2.40 ft³ ported
- Audioque SDC2.515 D4 2.83 ft³ sealed · 2.51 ft³ ported
- Machete M15 v2 D4 2.83 ft³ sealed · 2.33 ft³ ported
FAQ
What box does the Diamond CM315D2 need?
Recommended net volume: 2.79 ft³ sealed, 2.44 ft³ ported tuned to 33 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 Diamond CM315D2 Thiele/Small specs?
Fs 30 Hz, Qts 0.64, Vas 3.06 ft³, Xmax 0.43″, Sd 122.5 in².
What is the Diamond CM315D2 mounting depth?
Mounting depth is 7 3/8″, cutout diameter 13 15/16″. The inside depth of the box must exceed the mounting depth by at least 1″.