The FIESTA 20 is a simple-to-make and straightforward upright cabinetwith no complicated "extras".
As can be seen from the drawing, you will have to glue a reinforcing cross-piece between the two cut-outs for the bass speakers made up of a cross stiffener and a longitudinal stiffener.
The crossover unit of the FIESTA 20 is mounted on the rear panel behind the cut-out for the upper bass speaker.
The damping of the speaker uses eight mats of damping material pushed through the bass speaker cut-outs into the cabinet. The entire inside space of the speaker cabinet should be filled loosely with damping material.