Deaf Bonce Apocalypse DB-SA521NEO
21″ subwoofer · dual 1 Ω · 5,000 W RMS
Fs 23 HzQts 0.30Vas 6.77 ft³Xmax 1.18″
Recommended box
For a sedan, one sub, 5,000 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
| Net volume | 3.34 ft³ (94.5 L) |
|---|---|
| Qtc | 0.52 |
| Fc | 40 Hz |
| F3 (−3 dB, no cabin gain) | 61 Hz |
| Example box (outside) | 22 7/16″ × 22 7/16″ × 15 9/16″ |
Ported
| Net volume | 3.46 ft³ (98 L) |
|---|---|
| Tuning (Fb) | 31 Hz |
| Port | slot 3 3/8 × 21 13/16″, 51 5/8″ long |
| Port velocity at 5,000 W | 86 ft/s |
| F3 (−3 dB, no cabin gain) | 32 Hz |
| Example box (outside) | 31 1/2″ × 23 1/4″ × 17 15/16″ |
The volume and tuning are the recommendation, but the port doesn’t fit this example box. Size the box and port in the designer.
Open ported box in designerThiele/Small parameters
| Fs | 23 Hz |
|---|---|
| Qts | 0.30 |
| Qes | 0.316 |
| Qms | 6 |
| Vas | 6.77 ft³ |
| Re (one coil) | 0.7 Ω |
| Sd | ≈ 180.6 in² |
| Xmax | 1.18″ |
| EBP | 73 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 90.7 dB calc. |
General
| Size | 21″ |
|---|---|
| Voice coils | dual 1 Ω |
| RMS power | 5,000 W |
Mounting dimensions
| Cutout diameter | 19 7/16″ |
|---|---|
| Mounting depth | 13 1/8″ |
Only Qts is published — Qms assumed to be 6 and Qes calculated (barely affects box design).
“≈” 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.