Mapman, it took me a few years to minimize the box resonance from the boxes. Simply, I used test tones with a microphone/spl meter, my feel of the box and my ears, as well as a wide range of music to come up with my mods. I originally started with a brace at the front corners of the bass horns. I than used some resonant free aluminum bars(found at a surplus parts place in town),applying them one pair at a time. Until they passed my criteria. The wife is ok with them, because of the paint and vinyl tile I have used to make them room friendly. Some of these bars face horizontal,some vertical. I had done another pair prior, but overdamped the boxes. Not much more to say. MrD