Since we are using a premade flight case as the base for our speaker system's enclosure, all we have to do is cut a single panel that will hold the speakers, volume control, and power switch on a panel that is exposed. We can do this by opening the case, thus hiding the Pi, battery, and electronics behind it.

To make this panel, we will use a 3 mm medium density fiberboard (MDF); this is a cheap material and is very easy to work with.

First, we will need to cut a square of MDF that is just smaller than the opening in the flight case. To do this, first measure the length and width of the inside of the flight case and mark this distance away from two edges of a sheet of MDF, as shown in the following image:

Next, take a try square and draw a line parallel to each edge in line with the markings in order to give an outline of where the square needs to be cut to get our panel as shown in the following figure.