Audio System R08 EVO
8″ subwoofer · dual 4 Ω · 300 W RMS
Fs 39.9 HzQts 0.38Vas 0.41 ft³Xmax 0.63″
The published specs don’t add up:
- Fs, Vas and Sd don't match the moving mass of 50 g (they give 90 g) — one of the spec sheet values is probably wrong.
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
| Net volume | 0.32 ft³ (9 L) |
|---|---|
| Qtc | 0.57 |
| Fc | 60 Hz |
| F3 (−3 dB, no cabin gain) | 81 Hz |
| Example box (outside) | 10 1/4″ × 10 1/4″ × 9 1/4″ |
Ported
| Net volume | 0.64 ft³ (18 L) |
|---|---|
| Tuning (Fb) | 40 Hz |
| Port | round port Ø2 1/2″, 11 1/4″ long |
| Port velocity at 300 W | 167 ft/s |
| F3 (−3 dB, no cabin gain) | 37 Hz |
| Example box (outside) | 15 15/16″ × 15 3/4″ × 7 5/16″ |
Thiele/Small parameters
| Fs | 39.9 Hz |
|---|---|
| Qts | 0.38 |
| Qes | 0.43 |
| Qms | 3.1 |
| Vas | 0.41 ft³ |
| Re (one coil) | 3.45 Ω |
| Sd | 33.3 in² |
| Xmax | 0.63″ |
| Vd | 21 in³ calc. |
| Mms | 90 g calc. |
| BL | 13.4 T·m calc. |
| EBP | 93 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 84.3 dB calc. |
General
| Size | 8″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | 300 W |
Mounting dimensions
| Cutout diameter | 7″ |
|---|---|
| Mounting depth | 4 13/16″ |
| Overall diameter | 8 7/16″ |
“≈” 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.
Data sources
- audio-system.de/wp-content/uploads/2020/02/Manual-R08-EVO.pdf
- audio-system.de/produkte/subwoofer/radion-series/
Other Audio System 8″ models
- Audio System HX 08 SQ 8″ · 4 Ω
- Audio System R08 FLAT EVO3-D4 8″ · dual 4 Ω
- Audio System X08 EVO 8″ · dual 2 Ω