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 first speaker and to the positive post of the second speaker.
•The negative output terminal of the right channel connects to the negative input post of the first speaker and to the negative post of the second speaker.
The total impedance of equal speakers in parallel is found by dividing the impedance of one speaker by the number of speakers. For example, two eight ohm speakers in parallel is a four ohm load (eight ohms divided by two), four eight ohm speakers in parallel is a two ohm load (eight ohms divided by four).
Parallel connections are harder on the amplifier than series connections, as the total impedance is lower compared to driving a single speaker, and the amplifier must produce more current to drive them.
An example of a PARALLEL
connection between two speakers
Ideally, the total average impedance should be no less than 2 ohms per channel. You must make sure that the lower impedance does not cause the amplifier to overheat, shut down, blow the line fuse, or pop your circuit breaker. If this happens, you should reduce the number of speakers wired in parallel, rewire them in series, or use more than one power amplifier.
Technical Note about Multiple Speaker Connections
Although there are two possible connection types discussed in this manual, it is imperative that with either connection type that you use loudspeakers of the same type and nominal impedance for these connections. In doing so, you have the most predictable outcome for your installation. When speakers of different nominal impedances and/or different bandwidths are used, there are many other acoustic problems that come into play in addition to complex impedance at the amplifier’s speaker output terminals. If you must use multiple speakers on any individual amplifier channel, please use speakers as close to identical as possible.
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