Speaker Cabinet Calcs

This page contains a few tools that calculate the total load a speaker cabinet will put on your amplifier. Simply enter the ohm ratings of the various speakers in the boxes below them and the total should update automatically.

4 Speakers: serial/parallel

This configuration is the standard "4x12" layout. Speakers are wired in series in two pairs and these pairs are wired to the jack in parallel. If all speakers are the same rating then the total load should be the same.

2 Speakers: serial

The first of the two options for a 2-speaker cabinet. The speakers are wired in series to the jack. The loads of the speakers are added together.

2 Speakers: parallel

The second of the two options for a 2-speaker cabinet. The speakers are wired in parallel to the jack. The total load of the speakers is halved, if both speakers are of the same impedence.

Notes & Disclaimer

Genreally speaking, it is best for all the speakers in your cabinet to present the same load. Theoretically a speaker presenting a lower load will generate more power, so it will be louder than one presenting a higher load.

Valve amps and solid state amps behave differently. Ideally you should load the amp with the resistance it is expecting, but solid state amps will generally be more forgiving: if you give it a higher load you will simply get less power. With a valve amp it could actually be damaging. You should never plug an amp into less load than it is designed for.

A comprehensive guide can be found here.

I accept no responsibility for any damage you may cause to your amp or speakers after using these calculators.