If you have two loudspeakers that you want to power with a single channel amplifier, the first thing to do is to determine the output impedance of the amplifier and that of the speakers. Ideally, the amplifier's output impedance should match that of the speakers. If you can match the impedances, you will be able to properly use the speakers with the amplifier.
Steps
Method 1 of 2: Series Speakers
Step 1. If you connect the speakers in series, you are adding their impedances
Example: You have two 8 ohm speakers that you want to connect to an amplifier with an output impedance of 16 ohm. In this case, put the speakers in series, so that their total impedance is 8 + 8 = 16 ohms, which corresponds to that of the amplifier.
Step 2. Connect the negative (-) terminal of the amplifier to the negative terminal of the first speaker
Step 3. Connect the positive terminal of the first speaker to the negative of the second
Step 4. Connect the positive terminal of the second speaker to the positive terminal of the amplifier
Method 2 of 2: Parallel Speakers
Step 1. For a parallel connection, the resulting impedance is half that of the two speakers (assuming they have the same impedance)
Example: you have the same two speakers and the amplifier has a 4 ohm output. In this case, you have to connect the speakers in parallel, because the impedance would be 8/2 = 4 ohms, which still corresponds to the amplifier.
Step 2. Connect the negative (-) terminal of the amplifier to the negative terminal of speaker 1
Step 3. Connect the negative terminal of speaker 1 to that of speaker 2
Step 4. Connect the positive (+) terminal of the amplifier to the positive terminal of speaker 1
Step 5. Connect the positive terminal of speaker 1 to that of speaker 2
Advice
- More than two speakers can also be connected in parallel. If they have the same impedance, the resultant is that of a speaker divided by the number of speakers themselves. So the impedance of three 8 ohm speakers in parallel is 2.7 ohm.
- You can connect more than two speakers in series and also add impedance. Thus the impedance of one 8 ohm speaker and two 16 ohm speakers connected in series is 40 ohm.
Warnings
- If the impedance of the speakers is too low, you could damage the amplifier by trying to power them.
- Consult your amplifier manual for warnings, variations and exceptions, otherwise you could pay the costly consequences.
