Connecting 4-ohm speakers to an 8-ohm system involves connecting twice as many speakers. For example, if you have an 8-ohm system that requires two speakers, you can make an 8-ohm speaker by wiring two 4-ohm speakers in series. Wiring speakers in series adds speaker impedances together. So long as the amplifier or head unit sees the load for each speaker as 8 ohms, you will not damage it by connecting 4-ohm speakers to the system.
Locate channel one on the amplifier or head unit. Channel one should have positive and negative audio output terminals. These terminals are usually labelled "Audio Out." The positive terminal will be labelled "+" and the negative terminal will be labelled "-". If this system was going to use actual 8-ohm speakers, only one speaker would be connected to these two terminals. To use 4-ohm speakers, two speakers have to be connected to these two terminals.
Connect the positive terminal of speaker 1 to the negative terminal of speaker 2. This connects the two 4-ohm speakers in series.
Connect the negative terminal of speaker 1 to the negative terminal of channel one of the amplifier or head unit. Connect the positive terminal of speaker 2 to the positive terminal of channel one.
Repeat steps 1 through 3 for each pair of 4-ohm speakers that will be connected to a different channel of the amplifier or head unit. Once all of the speakers are connected, turn the audio system on and test the speakers. Let the system play for about an hour to make sure the amplifier or head unit does not overheat.
Things you need
- Two 4-ohm speakers
- One 8-ohm audio system
- Wire cutters
- Wire strippers
- Plastic twist caps