The deep bass runs 20-60Hz. The left hand side as you view the picture, is plenum-loaded, forced cancellation, infinite baffle bass. It was several years later, that I added the right hand side, bass. It's a sealed, 34 cubic footer, with 8x15 inch drivers, push-pull, slot load. It's the same...
There are many paths to nirvana. For me, I have chosen to use a wide-band mid-range, augmented. Once I heard the "tone" of a Tang-Band w8-1772 driver, I knew that I wanted it. However, left on it's own merits, to be used "full-range," left a thin lower mid-range, indeed. I asked myself, why...