Calculating Impedance Loads 
This calculator is intended to help you determine the impedance of a speaker or subwoofer wiring configuration. There are many ways you can connect multiple speakers together. The most common and best way is to connect them in parallel. You do this by connecting the positive speaker wire from the amp to the positive terminal on the first subwoofer. In the picture below, one channel is shown. 

Then, you connect the positive from that first subwoofer to the positive of the next subwoofer. You can connect as many speakers together like this as your amplifier can handle. Before you attempt this, be sure of what your amplifier can handle. If it says it can handle 2 ohms stereo,
don't connect more than four 8 ohm woofers or two 4 ohm woofers per channel. If you ignore this warning, you may destroy your amp/speakers, or cause a fire, so unless you are absolutely sure your amplifier is capable of handling lower impedance loads, don't try it! 

The formula above is for multiple subwoofers with the same impedance.
Example: You have three eight ohm woofers. Inserting the variables in the formula gives you the ratio 8/3. Eight divided by 3 gives you approximately 2.66 ohms. If your subwoofers were four ohm versions, you would get an answer of 4/3 or 1.33 ohms. This would cause a problem for most amplifiers. There are some high current competition amplifiers that can handle these lower impedances, but in general most amps won't run with this load. If you are not sure, contact the manufacturer of your amplifier. This also the same way you wire an amplifier in mono except in a mono wiring schematic you usually use the positive of one channel and the negative of the other channel. When you use a mono configuration, the impedance load at the amp is half as much. 
Explanation of Terms 
Rt is total impedance. 
Calculate 
To use this form, enter the impedance of one driver and the quantity of drivers you intend to use. Then just click the "Calculate Values" button, and the answers will appear in the empty text boxes. 
Enter Impedance Ohms Enter Number of Drivers 
Stereo Mono
Ohms 
