Sundown Audio U-6.5 D4
6.5″ subwoofer · dual 4 Ω · 500 W RMS
Fs 38.7 HzQts 0.47Vas 0.13 ft³Xmax 0.75″
Recommended box
For a sedan, one sub, 500 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 | 0.21 ft³ (6 L) |
|---|---|
| Qtc | 0.60 |
| Fc | 49 Hz |
| F3 (−3 dB, no cabin gain) | 62 Hz |
| Example box (outside) | 9 1/16″ × 9 1/16″ × 8 3/16″ |
Ported
| Net volume | 0.39 ft³ (11 L) |
|---|---|
| Tuning (Fb) | 29 Hz |
| Port | slot 1 15/16 × 14 5/16″, 226 7/16″ long |
| Port velocity at 500 W | 27 ft/s |
| F3 (−3 dB, no cabin gain) | 26 Hz |
| Example box (outside) | 31 1/2″ × 15 3/4″ × 19 1/8″ |
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 | 38.7 Hz |
|---|---|
| Qts | 0.47 |
| Qes | 0.5 |
| Qms | 7.24 |
| Vas | 0.13 ft³ |
| Re (one coil) | 3.31 Ω |
| Sd | 19.6 in² |
| Xmax | 0.75″ |
| Vd | 14.7 in³ calc. |
| Mms | 102 g calc. |
| BL | 12.8 T·m calc. |
| EBP | 77 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 78.4 dB calc. |
General
| Size | 6.5″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | 500 W |
Mounting dimensions
| Cutout diameter | 5 15/16″ |
|---|---|
| Mounting depth | 5 11/16″ |
| Overall diameter | 7 3/16″ |
| Magnet diameter | 5 1/2″ |
“≈” 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 Sundown Audio 6.5″ models
- Sundown Audio SA Classic 6.5 D2 6.5″ · dual 2 Ω
- Sundown Audio SA Classic 6.5 D4 6.5″ · dual 4 Ω
- Sundown Audio U-6.5 D2 6.5″ · dual 2 Ω
- Sundown Audio Xv2-6.5 S4 6.5″ · 4 Ω