We're trying to find better, cheaper options that won't require building smaller cabinets. But you haven't given us any information aside from what speakers you have, & one issue. How is your system set up? And are they close to the walls?
Otherwise there's nothing stopping you from just building a more shallow test cabinet if you think that will work better. But most of us have only built the cabinets as according to plan.
Building smaller cabinets may help your issue, but it isn't a guarantee, and may cause more issues than it solves, esp since it means creating a more square-shaped tower, which isn't ideal, and will likely cause more issues than it solves. (Standing waves within the cabinet especially)
You might also want to try front-porting them, esp if you keep them up against the walls.
