The right match pairs an amp’s RMS wattage at the sub’s final ohm load with the subwoofer’s RMS power handling.
For the full breakdown, see our best 10 Inch Subwoofer And Amp Combo guide.
The fix is knowing how to match amp to subwoofer ratings before you wire anything, and it comes down to two published numbers: RMS watts and ohms.
RMS stands for root mean square, the wattage an amp can deliver continuously, and it’s the number you trust. Peak or max ratings describe brief bursts, so they stay out of the matching math entirely.
Matching an Amp to a Subwoofer: Read These Numbers First
You match an amp to a sub by reading the specs in order: the sub’s RMS handling, its voice-coil configuration, the load your wiring produces, and the amp’s published RMS at that load.
- Find the sub’s RMS power handling on the product label or in the manual, usually written as watts RMS like “500W RMS.” Ignore peak and max power figures.
- Note the voice-coil configuration. A single voice coil (SVC) sub presents one fixed impedance. A dual voice coil (DVC) sub has two coils that can be wired together, so the same sub can present more than one load.
- Work out the final impedance your wiring creates. Series wiring adds impedances; parallel wiring halves equal impedances. The table below covers the common results.
- Check the amp’s RMS output at that same impedance. For a single 4-ohm SVC sub rated 500W RMS, the target is an amp that publishes roughly 500W RMS into 4 ohms and is stable at 4 ohms.
- With multiple subs, add the RMS ratings first. The sum becomes your amp target, then wire the group so the final impedance lands on a rating the amp actually publishes.
What Final Impedance Will Your Wiring Create?
Wiring determines the ohm load the amp sees. Equal-value coils or subs wired in series double the impedance; wired in parallel they halve it. Common results:
| Setup | Wiring | Load the Amp Sees |
|---|---|---|
| One SVC 4-ohm sub | Single coil | 4 ohms |
| One DVC 4-ohm sub | Coils in parallel | 2 ohms |
| One DVC 4-ohm sub | Coils in series | 8 ohms |
| One DVC 2-ohm sub | Coils in parallel | 1 ohm |
| One DVC 2-ohm sub | Coils in series | 4 ohms |
| Two SVC 4-ohm subs | Wired in parallel | 2 ohms |
| Two SVC 4-ohm subs | Wired in series | 8 ohms |
Pick the wiring that lands on an impedance number the amp publishes and is rated stable at. If the amp lists output at 1, 2, and 4 ohms, you have flexibility; if it only lists 4 and 2 ohms, don’t hand it a 1-ohm load.