Series and Parallel Speaker Connections
Whenever connecting more than one speaker per channel to an amplifier (regardless of the brand), you must consider the way in which the amplifier will be impacted by adding the additional speaker(s). Additionally, speakers with dual voice coils also apply to this consideration. Two voice coils in a single speaker also cause different reactions from an amplifier depending on the way in which they connect to the amplifier.
The connection of more than one speaker per channel will tend to degrade the speaker’s frequency response and may make the amplifier run hot. For the best sonic results, use one speaker per amplifier channel. If you must connect more than one speaker per channel, there are two methods in which to do so: Series or Parallel.
Series
A series connection is established when voice coils are connected in a string – end to end – so there’s only one way for audio signals to flow “in” and only one way for audio signals to flow “out”. For example, if you were to
•The positive output terminal of the right channel connects to the positive input post of the fi rst speaker.
•The negative input post of the fi rst speaker connects to the positive input post of the second speaker.
•The negative input post of the second speaker connects to the negative output terminal of the right channel.
An example of a SERIES connection between two speakers
The total impedance of speakers in series is found by adding their impedances together. For example, two four ohm speakers in series is an eight ohm load. Series connections are easier on the amplifier than parallel connections as the total impedance is higher than driving a single speaker.
Parallel
A parallel circuit is established when voice coils are connected in a way that there are multiple paths for audio signals to flow “in” and multiple paths for audio signals to flow “out”. When speakers are connected in parallel, the total resistance at the amplifier is proportionally divided based on the value of each individual voice coil resistance. The term “divided” simply means all of the values together in parallel are a SMALLER value than each all by itself. For example, if you were to parallel connect two speakers to the front right channel of the amplifier:
•The positive output terminal of the right channel connects to the positive input post of the fi rst speaker and to the positive post of the second speaker.
An example of a PARALLEL connection between two speakers
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