Power Two Speakers with a One Channel Amp
If you have two speakers you want to power from a single-channel amplifier, the first thing you should do is determine the output impedance of the amplifier and the impedance of your speakers. Ideally, the output impedance of the amplifier should match the impedance of the speakers. If you can make the impedances match, you'll be able to successfully use your speakers with the amplifier.
Steps
Speakers in Series
- If you connect the speakers in series, you're adding the speaker impedances together. Example: You have two 8 ohm speakers you want to connect to an amplifier with an output impedance of 16 ohms. For this case, you want to put your speakers in series, so the total impedance of the speakers will be 8+8=16 ohms, matching the amplifier.
- Plug the negative terminal (-) of the amplifier into the negative terminal of the first speaker.
- Connect the positive terminal of the first speaker to the negative terminal of the second speaker.
- Connect the positive terminal of the second speaker to the positive terminal of the amplifier.
Speakers in Parallel
- For a parallel connection of two speakers, the resulting impedance is half of the impedance of the speakers (assuming the speakers have the same impedance). Example: You have the same two speakers, but the amplifier has a 4 ohm output. For this case, you want to connect the speakers in parallel because the impedance would be 8/2=4 ohms, again matching the amplifier.
- Plug the negative terminal (-) of the amplifier to the negative terminal of both speakers.
- Plug the positive terminal (+) of the amplifier to the positive terminal of both speakers.
Tips
- You can also connect more than two speakers in parallel. If they have the same impedance, then the resulting impedance is the impedance of one speaker divided by the number of speakers. So the impedance of three 8 ohm speakers connected in parallel is 2.7 ohms.
- You can connect more than two speakers in series--and the impedance will also add. So the impedance of one 8 ohm speaker and two 16 ohm speakers connected in series is 40 ohms.
Warnings
- If the impedance of the speakers is too low, you could damage the amplifier trying to drive them.
- Please consult your amplifier manual for exceptions, variations and warnings, or you may have an expensive lesson.
