Ultra U-15 15" 2500w Car Audio Subwoofer
The Colossal Sounds Ultra 15" subwoofer combines high-output SPL performance with accurate daily-driver sound. This 15-inch ground-pounder is designed for strong, efficient output across a wide range of music.
Its cooling-focused motor assembly, non-pressed paper cone, carbon-fiber dust cap, Nomex spider pack, heavy-duty sewn-in lead wires, and cast-aluminum basket are engineered for durability, cone control, and consistent daily output.
Driver data
Technical information
Published specifications and enclosure guidance for planning your system.
General specifications
| RMS power handling | 2,500 Watts |
|---|---|
| Peak power handling | 5,000 Watts |
| Voice coil size | 3" |
| Voice coil configuration | Dual 1 Ω | Dual 2 Ω |
| XMAX (one way) | 33 mm |
| Product weight | 55 lbs |
| Build lead time | Approximately 2 weeks |
Thiele/Small (T/S) parameters
Measurement condition: Ultra 15" D2 — 3-hour break-in period
| Re — DC resistance | 3.1585 Ω |
|---|---|
| Fs — Free-air resonance | 30.8067 Hz |
| Qes — Electrical Q | 0.5028 |
| Qms — Mechanical Q | 4.9781 |
| Qts — Total Q | 0.4567 |
| Le — Voice coil inductance | 2.2718 mH at 1 kHz |
| Sd — Effective piston area | 79,173.0434 mm² (122.7185 in²) |
| Vas — Equivalent compliance volume | 73.5338 L (2.5968 ft³) |
| BL — Motor force factor | 19.8244 N/A |
| Mms — Moving mass | 323.2091 g |
| Cms — Mechanical compliance | 82.5786 µm/N |
| Sensitivity | 88.0579 dB @ 1 W/1 m |
Enclosure recommendations
| Recommended ported enclosure volume | 3–5 cu ft |
|---|---|
| Ported tuning | 32 Hz |
| Bandpass sealed-chamber volume | 1.5–2.5 cu ft |
The manufacturer lists this sealed-chamber volume for bandpass applications only.
Send us your subwoofer model, available space and performance goals.
Technical data source: View manufacturer specifications