Multiply this number by 2. 2 l b h P 2 l b b h h l S. We can provide you with comprehensive Subwoofer Box Calculator for online creating a high performance subwoofer enclosure.
So the volume as a function of x is given by V x x 25 - 2 x 20 - 2 x.
So if we cut X inches from our rectangle. Lets make it dependent on only length. For example by dragging the uppermost point which changes x we may make the dot on the graph that corresponds the volume of the box for a given x reach the local maximum point. First we should find a formula for the volume of our box.