Cut two pieces of plywood or mdf to 28 inches by 28 inches for the front and back of the 4x12 cabinet.
Build your own 4x12 guitar cabinet.
Draw circles for the speakers on the front panel of the cabinet with a compass or large protractor.
April 3 2014 this handbook covers all the major kinds of cab types you re likely to want to try and build from horn loaded subwoofers to 4x12 guitar cabs along with advice on dimensions fixings materials and.
Primarily the cabinet is a convenient way of housing the speaker so it should be solidly built to ensure no joint vibration unpleasant buzzing and be strong.
As guitar speakers are different so their cabinets are different.