Speaker Wiring
Series vs. Parallel Speaker Wiring
Series and parallel are the two ways to connect more than one speaker to a single amplifier. They look similar on the bench but do opposite things to the load.
Parallel: impedance goes down
Parallel ties all the positives together and all the negatives together. Each speaker gets the full amplifier voltage, and the total impedance drops. For identical speakers, divide one speaker's impedance by the number of speakers.
Two 8Ω speakers become 4Ω. Four 8Ω speakers become 2Ω — a load many amplifiers cannot safely drive, which is where impedance that is too low becomes a real concern.
Series: impedance goes up
Series chains the speakers one after another. The amplifier voltage is shared across them, and the total impedance rises. For identical speakers, multiply one speaker's impedance by the number of speakers.
Side by side
| Two 8Ω speakers | Total load | Effect |
|---|---|---|
| Parallel | 4Ω | Lower load, more current drawn |
| Series | 16Ω | Higher load, less current drawn |
Which should you use?
- Parallel is the default for most PA and home setups — amps generally deliver more power into lower impedance, as long as you stay within the amp's rating.
- Series is useful to keep a load from dropping too low, or for specific designs like some 70V/100V and guitar-cabinet wiring.
- Series-parallel combines both to run four or more speakers at a safe load — see connecting multiple speakers to one amplifier.