WooferGuy is reader-supported. When you buy through an Amazon link on this page we may earn a commission, at no extra cost to you. It never decides what we recommend. How this works.
Matching an amplifier to your subwoofers comes down to two numbers: the total RMS power of the subs, and the final impedance (load) you can wire them to. Get those right and the amp delivers what the subs can use without strain. This matcher works out every way to wire one to four subs, recommends the best load, tells you how much amp power to look for at that load, and shows which of the amps we cover fit.
- Add up the subs’ RMS ratings. Ignore peak or “max” power.
- Pick a final load the amp is rated for, usually 1 Ω or 2 Ω for mono amps.
- Look for an amp making 75–100% of the total RMS at that load. A little more is fine with careful gain setting.
- Use identical subs wired the same way so each gets equal power.
How the matcher works
Each dual voice coil sub can be wired with its coils in series (impedances add) or in parallel (one coil’s impedance divided by two). The matcher then joins the subs in parallel or series, and for four subs also tries two series pairs in parallel. It lists every distinct final load, from 0.25 Ω up, and recommends the load between 1 Ω and 4 Ω where an amp we cover is closest to your total RMS.
Amp matches use the makers’ published RMS ratings at each load. For non-standard loads, like the 2.67 Ω you get from three subs, it estimates the power from the rating at the next standard load below, since a voltage-limited amp makes roughly proportionally less power into a higher impedance. Those figures are marked with a tilde (~).
The wiring note estimates current draw for a Class D amp at about 80% efficiency on a 13.8 V system, the same method as our wire and fuse calculator, which handles exact run lengths and fuses.
Quick reference
| Your subs | Wire to | Total RMS | Amp to look for |
|---|---|---|---|
| 1 × DVC4, 600 W (e.g. Rockford P3D4-12) | 2 Ω | 600 W | 450–600 W at 2 Ω |
| 2 × DVC4, 500 W (e.g. Kicker CompR 12) | 1 Ω | 1,000 W | 750–1,000 W at 1 Ω |
| 2 × DVC2, 600 W | 2 Ω | 1,200 W | 900–1,200 W at 2 Ω |
| 1 × SVC4, 250 W | 4 Ω | 250 W | 200–250 W at 4 Ω |
| 4 × DVC2, 300 W | 1 Ω | 1,200 W | 900–1,200 W at 1 Ω |
For the wiring steps themselves, see our dual voice coil wiring guide; for setting the amp once it’s installed, our multimeter gain guide.
FAQs
Is a bigger amp than my subs’ RMS dangerous?
Not by itself. Clipping from a gain set too high is what usually damages subs. A slightly larger amp with the gain set correctly is fine.
Why does the matcher prefer 1 Ω or 2 Ω?
Most mono car amps make their most power at 1 Ω or 2 Ω. Very low loads like 0.5 Ω need an amp rated for them, and high loads like 8 Ω waste most amps’ power.
Can I use a 2-channel amp?
Yes, bridged. Check the amp’s minimum bridged load, which is often 4 Ω, and wire to suit. The matcher’s product picks are mono amps.
What about different subs on one amp?
Avoid it. Different impedances or sensitivities mean one sub works harder than the other.
How accurate are the estimates?
Ratings at standard loads come from manufacturer specs. Estimates for odd loads are approximate; real output also depends on your car’s voltage.