How to Make Parallel Connections

In short, in a parallel connection we connect positive to positive and negative to negative. This type of connection is generally used between speakers (both single and dual voice coil) and even with batteries. Below are examples of both the physical wiring using cables and the calculation to determine the resulting impedance.

Example 1:
In this example, we have two single 4-ohm speakers to be connected to a 2-ohm amplifier. How should the two speakers be connected to the amplifier output so it delivers its full power at 2 ohms?

Answer:
In this case, follow the rule of connecting positive to positive and negative to negative on each speaker coil. The resulting impedance can be calculated with a simple formula:

Speaker Impedance ÷ Number of Speakers = Resulting Impedance

So: 4 Ohms ÷ 2 Speakers = 2 Ohms

The image below illustrates this connection, showing that one positive and one negative lead will remain to be connected to the amplifier output.

Example 2:
In this example, we have 2 dual 2-ohm voice coil speakers to be connected to a 0.5-ohm amplifier.

Answer:
For this application, we can use a similar calculation as Example 1:

Speaker Impedance ÷ Number of Speakers = Resulting Impedance

So: 2 Ohms (impedance of each speaker coil) ÷ 4 (total number of coils in the dual setup) = 0.5 Ohms

 

The parallel connection of all coils is shown in the image below, leaving one positive wire and one negative wire to connect to the amplifier output.

 

 

Conclusion:
No matter the number of speakers or their individual impedances, in a parallel connection you always use division to calculate the final impedance of the connection.