Sky High Car Audio FE-6.5 D4
6.5″ subwoofer · dual 4 Ω · 300 W RMS
| Source | skyhighcaraudio.com · 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) | Boomy, with a bump · 1.12 |
|---|---|
| Fc | 66 Hz |
| F3 (−3 dB, no cabin gain) | 51 Hz |
| Example box (outside) | 9 1/16″ × 9 1/16″ × 7 3/16″ |
Ported
deeper, louder| Tuning (Fb) | 43 Hz |
|---|---|
| Port | slot 1 15/16 × 14 5/16″, 111 1/8″ long |
| Port velocity at 300 W | 24 ft/s |
| F3 (−3 dB, no cabin gain) | 35 Hz |
| Example box (outside) | 31 1/2″ × 15 3/4″ × 11 1/16″ |
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 designerDeeper: 0.78 ft³ (22 L) tuned to 38 Hz, 20 5/16″ × 15 3/4″ × 7 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 | 6.5″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | 300 W |
| Fs | 55.7 Hz |
| Qts | 0.94 |
| Qes | 1.09 |
| Qms | 6.84 |
| Vas | 0.07 ft³ |
| Re (one coil) | 3.2 Ω |
|---|---|
| Sd | 20 in² |
| Xmax | 0.43″ |
| Vd | 8.7 in³ calc. |
| Mms | 92 g calc. |
| BL | 9.7 T·m calc. |
| EBP | 51 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 77.2 dB calc. |
Mounting dimensions
| Cutout diameter | 5 13/16″ |
|---|---|
| Mounting depth | 4 5/8″ |
| Overall diameter | 6 15/16″ |
Cone area (Sd) calculated from Fs, Vas and Mms: 20 in².
“≈” 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 Sky High Car Audio 6.5″ models
- Sky High Car Audio BMX-6.5 D1 6.5″ · dual 1 Ω
- Sky High Car Audio BMX-6.5 D2 6.5″ · dual 2 Ω
- Sky High Car Audio FE-6.5 D2 6.5″ · dual 2 Ω
- Sky High Car Audio FMX-6.5 D1 6.5″ · dual 1 Ω
- Sky High Car Audio FMX-6.5 D2 6.5″ · dual 2 Ω
- Sky High Car Audio FXB-6.5 D2 6.5″ · dual 2 Ω
- Sky High Car Audio FXB-6.5 D4 6.5″ · dual 4 Ω
Similar 6.5″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- DC Audio M4 6.5 D4 0.19 ft³ sealed · 0.35 ft³ ported
- Sundown Audio Xv2-6.5 S4 0.18 ft³ sealed · 0.35 ft³ ported
- Ground Zero GZRW 6XSPL (2x2 Ohm) 0.21 ft³ sealed · 0.35 ft³ ported
- CT Sounds TROPO-6-5 D4 0.21 ft³ sealed · 0.35 ft³ ported
- Gladen Sigma SSW065 (DVC 2 ohm) 0.18 ft³ sealed · 0.35 ft³ ported
- Skar Audio EVL-65 D4 0.18 ft³ sealed · 0.35 ft³ ported
FAQ
What box does the Sky High Car Audio FE-6.5 D4 need?
Recommended net volume: 0.18 ft³ sealed, 0.35 ft³ ported tuned to 43 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 Sky High Car Audio FE-6.5 D4 Thiele/Small specs?
Fs 55.7 Hz, Qts 0.94, Vas 0.07 ft³, Xmax 0.43″, Sd 20 in².
What is the Sky High Car Audio FE-6.5 D4 mounting depth?
Mounting depth is 4 5/8″, cutout diameter 5 13/16″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Sky High Car Audio FE-6.5 D4 handle and how do I wire it?
RMS power rating: 300 W. Dual 4 Ω voice coils: series gives 8 Ω, parallel gives 2 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.