I remember building my first 2 cubic ft. air-suspension speaker in the late 60s before boxplots. My first mistake was assuming that since I knew how to build cabinets that I knew how to build speakers. WRONG!! The thin cabinet walls of my first speaker modulated and cancelled out a good portion of the bass from my 12" woofer.

Since that first speaker disaster, I slowly graduated into redesigning and building old classic horn speakers with success.