Audison Prima APBMW S8-4.2 (BMW/MINI underseat, SVC 4 ohm)
8″ subwoofer · 4 Ω · 150 W RMS
40 HzFs, resonance
0.65Qts
0.74 ft³Vas
0.28″Xmax
150 WRMS
Recommended box
For a sedan, one sub, 150 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, tighter0.71 ft³ (20 L)
Net volume
| Qtc | 0.93 |
|---|---|
| Fc | 57 Hz |
| F3 (−3 dB, no cabin gain) | 49 Hz |
| Example box (outside) | 10 5/8″ × 10 5/8″ × 16 1/2″ |
Ported
deeper, louder1.20 ft³ (34 L)
Net volume
| Tuning (Fb) | 39 Hz |
|---|---|
| Port | slot 1 9/16 × 14 5/16″, 29 1/8″ long |
| Port velocity at 150 W | 28 ft/s |
| F3 (−3 dB, no cabin gain) | 34 Hz |
| Example box (outside) | 31 1/2″ × 15 3/4″ × 8 1/2″ |
Thiele/Small parameters
| Fs | 40 Hz |
|---|---|
| Qts | 0.65 |
| Qes | 0.96 |
| Qms | 2 |
| Vas | 0.74 ft³ |
| Re | 3.8 Ω |
| Sd | 30.8 in² |
| Xmax | 0.28″ |
| Vd | 8.5 in³ calc. |
| Mms | 42 g calc. |
| BL | 6.5 T·m calc. |
| EBP | 42 — suits sealed calc. |
| Sensitivity, 1 W / 1 m | 83.5 dB calc. |
General
| Size | 8″ |
|---|---|
| Voice coils | 4 Ω |
| RMS power | 150 W |
Mounting dimensions
| Cutout diameter | ≈ 7 5/16″ |
|---|---|
| Mounting depth | ≈ 3 15/16″ |
“≈” 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.