System Design Card
This is the one-screen card for the most common early design decisions: power wire, fuse, crossover start, and a quick power-check rule.
Tiny Version
Protect the wire, not the ego. Start with sane crossover bands, size the main cable to the real power, and confirm the load before you chase loudness.
Main Wire Quick Start
| Total system power | Main wire | Main fuse |
|---|---|---|
| Up to 500 W | 8 AWG | 50 A |
| 500 to 1000 W | 4 AWG | 80 A |
| 1000 to 2000 W | 2 AWG | 125 A |
| 2000 to 3000 W | 0 AWG | 175 A |
| 3000 W and up | 00 AWG or larger | 200 A and up |
Crossover Starts
- Sub only - LPF around 80 Hz
- Front speakers - HPF around 60 to 80 Hz
- Small front speakers - HPF around 100 to 120 Hz
- Ported box - subsonic around 0.7 to 0.8 times tuning as a safe early check
Power Check
Target voltage for gain setting:
V = sqrt(P x R)
Use RMS power and the actual load, not marketing max power.
Do Not Forget
- Main fuse near the battery
- Ground should match the positive path quality
- Actual load matters more than the nominal sticker
- Measure voltage drop under load before buying more parts