Series vs Parallel Speaker Wiring

When you connect multiple speakers to an amplifier, the wiring method determines the total impedance your amp sees. The two fundamental methods are series and parallel — and they have opposite effects on impedance.

Getting this right matters. The wrong total impedance can damage your amp or rob you of power. Here's how each method works and when to use it.

The Core Difference

Series Wiring in Detail

In a series circuit, the speakers are daisy-chained. The signal passes through Speaker 1, then through Speaker 2, and back to the amp. There's only one path for the current to flow.

The maths

Add the impedances together. That's it.

How it's wired

Connect the negative (−) terminal of Speaker 1 to the positive (+) terminal of Speaker 2. The remaining free terminals (Speaker 1's positive and Speaker 2's negative) connect to the amp or jack socket.

Power distribution

In series, the same current flows through all speakers. But power distribution depends on each speaker's impedance. Higher impedance speakers receive more power in a series circuit. With matched speakers, power is split equally.

When to use series

When you need to increase the total impedance — typically to match an amp that requires a higher load. Less common in guitar setups because most amps have 4Ω, 8Ω, and 16Ω outputs, and series wiring can push the total above these standard values.

Parallel Wiring in Detail

In a parallel circuit, every speaker is connected directly across the amp's output. All positives together, all negatives together. The signal reaches each speaker independently.

The maths

For identical speakers, divide one speaker's impedance by the number of speakers. For mixed values, use the reciprocal formula.

How it's wired

Connect all positive (+) terminals together and route them to the jack tip (or amp positive output). Connect all negative (−) terminals together and route them to the jack sleeve (or amp negative output). Each speaker gets a direct connection to the amp.

Power distribution

In parallel, the same voltage appears across all speakers. But power distribution depends on impedance. Lower impedance speakers receive more power in a parallel circuit. With matched speakers, power is split equally.

When to use parallel

When you need to decrease the total impedance — or maintain it when adding speakers. This is the most common wiring method. When you plug two cabs into an amp head, they're wired in parallel. When a cab has a single pair of speakers, they're usually in parallel.

Side-by-Side Comparison

Series-Parallel: The Best of Both

Most 4×12 cabinets use series-parallel wiring — pairs of speakers wired in series, then the pairs connected in parallel. This keeps the total impedance in a usable range while distributing power evenly.

For example: four 16Ω speakers. Two pairs, each wired in series (16+16 = 32Ω per pair). The two 32Ω pairs wired in parallel (32 ∥ 32 = 16Ω total). The cab impedance equals a single speaker's impedance — clean and predictable.

For a full walkthrough with diagrams, see How to Wire a 4×12 Guitar Cabinet.

Which Should I Use?

Two speakers, want lower impedance? Parallel. Two 8Ω speakers in parallel = 4Ω.

Two speakers, want higher impedance? Series. Two 8Ω speakers in series = 16Ω.

Four speakers, want to keep impedance manageable? Series-parallel. Four 16Ω speakers = 16Ω total.

Plugging two cabs into one amp? They'll be in parallel (both plugged into the amp's outputs). Two 8Ω cabs = 4Ω. Make sure your amp handles it.

Not sure? Use the calculator to try different configurations and see the total impedance, power distribution, and safety status for each.