For best results the output resistance of the amplifier must equal the combined resistance of the speakers. So if the amps says 8 ohms and you have two 4 ohm speakers you put them is series or if the amps says 4ohms and you have two 8 ohm speakers put them in series. If it says 4ohm and you have two 4 ohm speakers best to use only one. It Depends on the output resistance of the amps. It is usually written at the terminals where the speakers are connected.
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For best results the output resistance of the amplifier must equal the combined resistance of the speakers. So if the amps says 8 ohms and you have two 4 ohm speakers you put them is series or if the amps says 4ohms and you have two 8 ohm speakers put them in series. If it says 4ohm and you have two 4 ohm speakers best to use only one. It Depends on the output resistance of the amps. It is usually written at the terminals where the speakers are connected.