Speaker wiring calculator
Total impedance for series, parallel and series-parallel wiring of 2–8 speakers, checked against your amplifier's minimum stable load. Enter each speaker's rated impedance — they don't have to match.
Check the amp's spec sheet or rear panel for "minimum impedance" or "stable down to". Most home receivers are 6 or 8 Ω; many PA and car amps are 2 or 4 Ω stable.
| Wiring | Total load | Verdict |
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The three ways to wire multiple speakers
Series — speakers chained + to − to + to − — adds impedance: Z = Z₁ + Z₂ + … + Zₙ. Easiest on the amp (highest load), but one dead speaker breaks the whole chain and the amp's power splits unevenly if impedances differ.
Parallel — every speaker's + and − wired straight to the amp's + and − — divides impedance: 1/Z = 1/Z₁ + 1/Z₂ + … + 1/Zₙ. Lowest load, so it's the one most likely to fall below what the amp can drive safely.
Series-parallel — speakers grouped into matched pairs wired in series, then the pairs wired to the amp in parallel — lands between the two, and is the standard way to run four identical speakers off a two-channel amp. It needs an even count of matched speakers, which is why the calculator only fills it in when that's true.
Reading the verdict
Safe means the total load sits comfortably above the amp's stated minimum. Marginal means it's at or just above the minimum — the amp will run hotter and work harder, so give it ventilation and keep an eye on it at high volume. Unsafe means the load is below what the amp is rated for: it can overheat, clip hard, trigger protection, or in the worst case damage the output stage. When in doubt, wire toward the higher-impedance option.
FAQ
Can I mix speakers with different impedances?
Electrically yes — series and parallel totals above work for any mix. But in parallel wiring the lower-impedance speaker draws more power and plays louder, unbalancing the pair; in series the higher-impedance one gets less power. Matched speakers are strongly preferred for anything but a quick test.
Why not just always wire in series for the safest, highest load?
You can, but series wiring puts all speakers on one loop, so cable resistance and any dead unit affects every speaker, and unmatched drivers get unequal power. Parallel and series-parallel are more forgiving to work on and keep each speaker's level independent, provided the resulting load is a fit for the amp.
Does the amp really care about the exact ohm number, or just "roughly"?
It cares about not going below the rated minimum, not about hitting an exact number — 5.3 Ω on a 4 Ω-stable amp is fine. Going under the minimum is the thing that causes problems, and the margin an amp has above that number varies by design, which is why "marginal" is worth treating with caution rather than dismissing.